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  • 401.
    Yan, Hongji
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Glykovetenskap.
    Chircov, Cristina
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Glykovetenskap.
    Zhong, Xueying
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Medicinteknik och hälsosystem.
    Winkeljann, Benjamin
    Tech Univ Munich, Dept Mech Engn, Boltzmannstr 11, D-85748 Garching, Germany.;Tech Univ Munich, Munich Sch Bioengn, Boltzmannstr 11, D-85748 Garching, Germany..
    Dobryden, Illia
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap.
    Nilsson, Harriet Elisabeth
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH). Karolinska Inst, Dept Biosci & Nutr, S-14183 Huddinge, Sweden..
    Lieleg, Oliver
    Tech Univ Munich, Dept Mech Engn, Boltzmannstr 11, D-85748 Garching, Germany.;Tech Univ Munich, Munich Sch Bioengn, Boltzmannstr 11, D-85748 Garching, Germany..
    Claesson, Per M.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap.
    Hedberg, Yolanda
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap.
    Crouzier, Thomas
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Glykovetenskap.
    Reversible Condensation of Mucins into Nanoparticles2018Inngår i: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 34, nr 45, s. 13615-13625Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Mucins are high molar mass glycoproteins that assume an extended conformation and can assemble into mucus hydrogels that protect our mucosal epithelium. In nature, the challenging task of generating a mucus layer, several hundreds of micrometers in thickness, from micrometer-sized cells is elegantly solved by the condensation of mucins inside vesicles and their on-demand release from the cells where they suddenly expand to form the extracellular mucus hydrogel. We aimed to recreate and control the process of compaction for mucins, the first step toward a better understanding of the process and creating biomimetic in vivo delivery strategies of macromolecules. We found that by adding glycerol to the aqueous solvent, we could induce drastic condensation of purified mucin molecules, reducing their size by an order of magnitude down to tens of nanometers in diameter. The condensation effect of glycerol was fully reversible and could be further enhanced and partially stabilized by cationic cross-linkers such as calcium and polylysine. The change of structure of mucins from extended molecules to nano-sized particles in the presence of glycerol translated into macroscopic rheological changes, as illustrated by a dampened shear-thinning effect with increasing glycerol concentration. This work provides new insight into mucin condensation, which could lead to new delivery strategies mimicking cell release of macromolecules condensed in vesicles such as mucins and heparin.

  • 402.
    Yan, Hongji
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Glykovetenskap.
    Seignez, Cedric
    Uppsala Univ, Dept Med Cell Biol, Div Integrat Physiol, S-75123 Uppsala, Sweden..
    Hjorth, Morgan
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Glykovetenskap.
    Winkeljann, Benjamin
    Tech Univ Munich, Dept Mech Engn, Boltzmannstr 11, D-85748 Garching, Germany.;Tech Univ Munich, Munich Sch Bioengn, Boltzmannstr 11, D-85748 Garching, Germany..
    Blakeley, Matthew
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Glykovetenskap.
    Lieleg, Oliver
    Tech Univ Munich, Dept Mech Engn, Boltzmannstr 11, D-85748 Garching, Germany.;Tech Univ Munich, Munich Sch Bioengn, Boltzmannstr 11, D-85748 Garching, Germany..
    Phillipson, Mia
    Uppsala Univ, Dept Med Cell Biol, Div Integrat Physiol, S-75123 Uppsala, Sweden..
    Crouzier, Thomas
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Glykovetenskap.
    Immune-Informed Mucin Hydrogels Evade Fibrotic Foreign Body Response In Vivo2019Inngår i: Advanced Functional Materials, ISSN 1616-301X, E-ISSN 1616-3028, artikkel-id 1902581Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The immune-mediated foreign body response to biomaterial implants can trigger the formation of insulating fibrotic capsules that can compromise implant function. To address this challenge, the intrinsic bioactivity of the mucin biopolymer, a heavily glycosylated protein that forms the protective mucus gel covering mucosal epithelia, is leveraged. By using a bioorthogonal inverse electron demand Diels-Alder reaction, mucins are crosslinked into implantable hydrogels. It is shown that mucin hydrogels (Muc-gels) modulate the immune response driving biomaterial-induced fibrosis. Muc-gels do not elicit fibrosis 21 days after implantation in the peritoneal cavity of C57Bl/6 mice, whereas medical-grade alginate hydrogels are covered by fibrous tissues. Further, Muc-gels dampen the recruitment of innate and adaptive immune cells to the gel and trigger a pattern of very mild activation marked by a noticeably low expression of the fibrosis-stimulating transforming growth factor beta 1 cytokine. Macrophages recruited to Muc-gels upregulate the gene expression of the protein inhibitor of activated STAT 1 (PIAS1) and SH2-containing phosphatase 1 (SHP-1) cytokine regulatory proteins, which likely contributes to their low cytokine expression profiles. With this advance in mucin materials, an essential tool is provided to better understand mucin bioactivities and to initiate the development of new mucin-based and mucin-inspired "immune-informed" materials for implantable devices subject to fibrotic encapsulation.

  • 403.
    Yang, Hao
    et al.
    Dalian Univ Technol, State Key Lab Fine Chem, IAP, Dalian 116024, Peoples R China..
    Li, Fusheng
    Dalian Univ Technol, State Key Lab Fine Chem, IAP, Dalian 116024, Peoples R China..
    Wu, Xiujuan
    Dalian Univ Technol, State Key Lab Fine Chem, IAP, Dalian 116024, Peoples R China..
    Zhang, Peili
    Dalian Univ Technol, State Key Lab Fine Chem, IAP, Dalian 116024, Peoples R China..
    Li, Wenlong
    Dalian Univ Technol, State Key Lab Fine Chem, IAP, Dalian 116024, Peoples R China..
    Cao, Suyan
    Dalian Univ Technol, State Key Lab Fine Chem, IAP, Dalian 116024, Peoples R China..
    Shan, Yu
    Dalian Univ Technol, State Key Lab Fine Chem, IAP, Dalian 116024, Peoples R China..
    Sun, Licheng
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi. Dalian Univ Technol, State Key Lab Fine Chem, IAP, Dalian 116024, Peoples R China.
    Improving the performance of water splitting electrodes by composite plating with nano-SiO22018Inngår i: Electrochimica Acta, ISSN 0013-4686, E-ISSN 1873-3859, Vol. 281, s. 60-68Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The electrochemical splitting of water requires efficient functional electrodes. Herein, we report the fabrication of electrocatalyst consisted of an electrodeposited NiFeP alloy film which was composite plated with nano-SiO2 on nickel foam. The structure and morphology of the film were characterized by X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results showed that the surface area of this NiFeP-SiO2 co-deposition alloy film can be significantly increased after electrochemical etching in a KOH solution. The water splitting properties of the alloy film were evaluated using electrochemistry. By using the NiFeP-SiO2/NF(Etched) as a bifunctional electrode, total water splitting has been demonstrated in a two-electrode cell with a current density of 10 mAcm(-2) at an applied voltage of 1.57 V, which exhibited enhanced water splitting activity in comparison to the analogue cell using the pristine NiFeP/NF electrode.

  • 404. Yang, L.
    et al.
    Lindblad, R.
    Gabrielsson, Erik
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Organisk kemi.
    Boschloo, G.
    Rensmo, H.
    Sun, L.
    Hagfeldt, A.
    Edvinsson, T.
    Johansson, E. M. J.
    Experimental and Theoretical Investigation of the Function of 4- tert -Butyl Pyridine for Interface Energy Level Adjustment in Efficient Solid-State Dye-Sensitized Solar Cells2018Inngår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 10, nr 14, s. 11572-11579Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    4-tert-Butylpyridine (t-BP) is commonly used in solid state dye-sensitized solar cells (ssDSSCs) to increase the photovoltaic performance. In this report, the mechanism how t-BP functions as a favorable additive is investigated comprehensively. ssDSSCs were prepared with different concentrations of t-BP, and a clear increase in efficiency was observed up to a maximum concentration and for higher concentrations the efficiency thereafter decreases. The energy level alignment in the complete devices was measured using hard X-ray photoelectron spectroscopy (HAXPES). The results show that the energy levels of titanium dioxide are shifted further away from the energy levels of spiro-OMeTAD as the t-BP concentration is increased. This explains the higher photovoltage obtained in the devices with higher t-BP concentration. In addition, the electron lifetime was measured for the devices and the electron lifetime was increased when adding t-BP, which can be explained by the recombination blocking effect at the surface of TiO2. The results from the HAXPES measurements agree with those obtained from density functional theory calculations and give an understanding of the mechanism for the improvement, which is an important step for the future development of solar cells including t-BP.

  • 405.
    Yang, Wenxing
    et al.
    Uppsala Univ, Angstrom Lab, Dept Chem, Box 523, SE-75120 Uppsala, Sweden.;Imperial Coll London, Dept Chem, London SW7 2AZ, England..
    Hao, Yan
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Tillämpad fysikalisk kemi.
    Kloo, Lars
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Tillämpad fysikalisk kemi.
    Boschloo, Gerrit
    Uppsala Univ, Angstrom Lab, Dept Chem, Box 523, SE-75120 Uppsala, Sweden..
    Carrier Dynamics of Dye Sensitized-TiO2 in Contact with Different Cobalt Complexes in the Presence of Tri(p-anisyl)amine Intermediates2018Inngår i: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 122, nr 26, s. 14345-14354Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Heterogeneous charge transfer processes at sensitized wide bandgap semiconductor surfaces are imperative for both fundamental knowledge and technical applications. Herein, we focus on the investigation of carrier dynamics of a triphenylamine-based dye, LEG4, sensitized TiO2 (LEG4/TiO2) in contact with two types of electrolyte systems: pure cobalt-based electrolytes and in combination with an organic donor, tri(p-anisyl)amine (TPAA). Four different cobalt redox systems with potentials spanning a 0.3 V range were studied, and the carrier recombination and regeneration kinetics were monitored both at low and at high TiO2 (e(-)) densities (1.3 X 10(18) and 1.3 X 10(19) cm(-3), respectively). The results reveal that the introduction of the TPAA intermediate more effectively suppress the recombination loss of TiO2 (e(-)) under high charge conditions, close to open-circuit, as compared to low charge conditions. As a result, the charge transfer from the cobalt complexes to the oxidized dyes is significantly improved by the addition of TPAA. Dye-sensitized solar cells fabricated with the TPAA-containing electrolytes demonstrate remarkable improvement in both V-OC and J(SC) and lead to more than 25% increase of the light-to-electricity conversion efficiency. Furthermore, an unprecedented detrimental impact of TPAA on the device performance was identified when the redox potential of the TPAA donor and the cobalt complexes are close. This is ascribed to the formation of TPAA(center dot+) which can act as an active recombination centers and thus lower the solar cell performance. These insights point at a strategy to enhance the lifetimes of electrons generated in sensitized semiconductor electrodes by overcoming the charge recombination between TiO2 and the oxidized dye under high carrier densities in the semiconductor substrate and offer practical guidance to the design of future efficient electrolyte systems for dye-sensitized solar cells.

  • 406.
    Yang, Xichuan
    et al.
    Dalian Univ Technol, State Key Lab Fine Chem, Linggong Rd 2, Dalian 116024, Liaoning, Peoples R China..
    Wang, Weihan
    Dalian Univ Technol, State Key Lab Fine Chem, Linggong Rd 2, Dalian 116024, Liaoning, Peoples R China..
    Zhang, Yanyun
    Dalian Univ Technol, State Key Lab Fine Chem, Linggong Rd 2, Dalian 116024, Liaoning, Peoples R China..
    Sun, Licheng
    KTH, Skolan för kemivetenskap (CHE), Centra, Molekylär elektronik, CMD. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi.
    Improving the power conversion efficiency of solid state dye sensitized solar cells with a N-oxoammonium salt: 2,2,6,6-Tetramethyl-1-oxopiperidinebromide2018Inngår i: Solar Energy, ISSN 0038-092X, E-ISSN 1471-1257, Vol. 170, s. 1001-1008Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    P-type doping is a rational strategy for the enhancement of hole transporting properties of the organic semiconductors as well as the device performance of organic photo-electric devices. We originally introduce a stable and solution processed p-type dopant based on N-oxoammonium salts termed 2,2,6,6-tetramethyl-1-oxopiperidinebromide salt (TEMPO-Br) for 2,2',7,7'-tetrakis(N, N-di-p-methoxyphenyl-amine)9,9'-spirobifluorene (Spiro-OMeTAD) based solid state dye sensitized solar cells (ssDSC). By introducing TEMPO-Br doped Spiro-OMeTAD and a commercialized D-pi-A sensitizer into ssDSCs, a promising device performance of 6.83% is achieved under simulated AM 1.5G solar irradiation (100 mW cm(-2)), which is significantly better than the control devices ( similar to 1.7 times). The doping effect of TEMPO-Br on the photophysical and electrochemical properties of Spiro-OMeTAD, solid state device performance, cationic dye regeneration kinetics and preliminary long-term stability have been systematically investigated. This work indicates a potential application of N-oxoammonium salts as chemical P-type dopants for triphenylamine based hole transporting materials in solid state photo-electric devices.

  • 407.
    Ye, Lu
    et al.
    Dalian Univ Technol, DUT KTH Joint Educ & Res Ctr Mol Devices, State Key Lab Fine Chem, Dalian 116024, Peoples R China..
    Gao, Yan
    Dalian Univ Technol, DUT KTH Joint Educ & Res Ctr Mol Devices, State Key Lab Fine Chem, Dalian 116024, Peoples R China..
    Cao, Shuyan
    Dalian Univ Technol, DUT KTH Joint Educ & Res Ctr Mol Devices, State Key Lab Fine Chem, Dalian 116024, Peoples R China..
    Chen, Hu
    Dalian Univ Technol, DUT KTH Joint Educ & Res Ctr Mol Devices, State Key Lab Fine Chem, Dalian 116024, Peoples R China..
    Yao, Yanan
    Dalian Univ Technol, DUT KTH Joint Educ & Res Ctr Mol Devices, State Key Lab Fine Chem, Dalian 116024, Peoples R China..
    Hou, Jungang
    Dalian Univ Technol, DUT KTH Joint Educ & Res Ctr Mol Devices, State Key Lab Fine Chem, Dalian 116024, Peoples R China..
    Sun, Licheng
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi.
    Assembly of highly efficient photocatalytic CO2 conversion systems with ultrathin two-dimensional metal-organic framework nanosheets2018Inngår i: Applied Catalysis B: Environmental, ISSN 0926-3373, E-ISSN 1873-3883, Vol. 227, s. 54-60Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    An ultrathin two-dimensional Zn porphyrin-based metal-organic framework (Zn-MOF nanosheets) is developed and used for the first time in photoreduction of CO2 to CO. Consequently, two novelty noble-metal-free hybrid photocatalytic systems are established and displayed outstanding photocatalytic activity and selectivity for CO evolution under mild photocatalytic reaction conditions. The insight revealed Zn-MOF nanosheets as photo sensitizer displays a better charge transport ability and longer lifetime of the photogenerated electron-hole pairs than the Zn-MOF bulk, which are confirmed by photoelectrochemical impedance and photoluminescence (PL) measurements. These studies show that the development of noble-metal-free photocatalytic systems and various MOF-based materials for photocatalytic applications are promising.

  • 408.
    Ye, Xinchen
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Hedenqvist, Mikael S.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Langton, Maud
    Lendel, Christofer
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Tillämpad fysikalisk kemi.
    On the role of peptide hydrolysis for fibrillation kinetics and amyloid fibril morphology2018Inngår i: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 8, nr 13, s. 6915-6924Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Self-assembly of proteins into amyloid-like nanofibrils is not only a key event in several diseases, but such fibrils are also associated with intriguing biological function and constitute promising components for new biobased materials. The bovine whey protein beta-lactoglobulin has emerged as an important model protein for the development of such materials. We here report that peptide hydrolysis is the rate-determining step for fibrillation of beta-lactoglobulin in whey protein isolate. We also explore the observation that beta-lactoglobulin nanofibrils of distinct morphologies are obtained by simply changing the initial protein concentration. We find that the morphological switch is related to different nucleation mechanisms and that the two classes of nanofibrils are associated with variations of the peptide building blocks. Based on the results, we propose that the balance between protein concentration and the hydrolysis rate determines the structure of the formed nanofibrils.

  • 409.
    Ye, Xinchen
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Polymera material.
    Junel, Kristina
    RISE Bioecon Innventia AB, Drottning Kristinas Vag 61, SE-11486 Stockholm, Sweden..
    Gallstedt, Mikael
    SIG Combibloc, Vasagatan 7, SE-11120 Stockholm, Sweden..
    Langton, Maud
    SLU Swedish Agr Univ, Dept Mol Sci, Box 7015, S-75007 Uppsala, Sweden..
    Wei, Xin-Feng
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Polymera material.
    Lendel, Christofer
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Tillämpad fysikalisk kemi.
    Hedenqvist, Mikael S.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Polymera material.
    Protein/Protein Nanocomposite Based on Whey Protein Nanofibrils in a Whey Protein Matrix2018Inngår i: ACS Sustainable Chemistry and Engineering, ISSN 2168-0485, Vol. 6, nr 4, s. 5462-5469Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This article describes nanocomposite films with separately grown protein nanofibrils (PNFs) in a nonfibrillar protein matrix from the same protein starting material (whey). Tensile tests on the glycerol-plasticized films indicate an increased elastic modulus and a decreased extensibility with increasing content of PNFs, although the films are still ductile at the maximum PNF content (15 wt %). Infrared spectroscopy confirms that the strongly hydrogen-bonded beta-sheets in the PNFs are retained in the composites. The films appear with a PNF-induced undulated upper surface. It is shown that micrometer-scale spatial variations in the glycerol distribution are not the cause of these undulations. Instead, the undulations seem to be a feature of the PNF material itself. It was also shown that, apart from plasticizing the protein film, the presence of glycerol seemed to favor to some extent exfoliation of stacked beta-sheets in the proteins, as revealed by X-ray diffraction.

  • 410.
    Ye, Xinchen
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Lendel, Christofer
    KTH, Tidigare Institutioner (före 2005), Bioteknologi. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Tillämpad fysikalisk kemi.
    Langton, Maud
    Olsson, Richard
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Polymera material.
    Hedenqvist, Mikael S.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Polymera material.
    Protein nanofibrils: Preparation, properties, and possible applications in industrial nanomaterials.2019Inngår i: Industrial Applications of Nanomaterials, Elsevier, 2019, s. 29-63Kapittel i bok, del av antologi (Annet vitenskapelig)
  • 411.
    Yin, Litao
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap. University of Science and Technology Beijing.
    FEM Modelling of Micro-galvanic Corrosion in Al Alloys Induced by Intermetallic Particles: Exploration of Chemical and Geometrical Effects2018Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Localized corrosion, such as pitting, crevice corrosion or galvanic corrosion, is a long-standing phenomenon that can greatly limit the life of metallic materials. For decades experimental methods have been used to try to understand the underlying physical, chemical and electrochemical processes that control localized corrosion in order to find effective protection methods against its propagation. The complexity of the phenomenon and its small geometric size have often severely restricted the basic understanding of local corrosion. In recent decades, computational methods have been developed as an alternative to the experimental methods. Compared to experimental methods, modeling and numerical simulation enable complicated systems to be systematically investigated without considering the inherent constraints of experimental methods.

        In the current Doctoral thesis, advanced calculation methodology has been used to study galvanic corrosion of an aluminum alloy with geometric resolution at micrometer level. The computational platform has been a commercial FEM-based software, COMSOL Multiphysics, which was combined with another software, Matlab. The current model system consists of a semi-spherical intermetallic particle, surrounded by a pure aluminum matrix. The aluminum surface is covered by an inert passive film, except for a ring-shaped surface around the particle itself. By assuming that the particle is electrochemically more noble than aluminum, it acts as a cathode and the surrounding aluminum ring as anode. By utilizing the FEM-based software, it has been possible to incorporate important physicochemical reactions, including the electrochemical anode and cathode reactions of the individual phases, mass transport of various chemical compounds formed during ongoing electrochemistry, homogeneous reactions in the electrolyte, as well as deposition of corrosion products consisting of Al(OH)3 along parts of the anodic area.

        What has made this study a significant step forward is that not only chemical changes but also geometrical changes have been taken into consideration in the simulation of ongoing micro-galvanic corrosion. Particularly challenging has been to mathematically master the gradual deposition of compact Al(OH)3 on an aluminum surface which gradually dissolves anodically. In the initial modeling work, the deposition of Al(OH)3 was assumed to occur only on the electrode surface, resulting in a gradual blockage of surface activity. In an even more advanced stage, the modeling has also sought to simulate the effect of a deposited porous film of Al(OH)3, formed through homogeneous reactions in the electrolyte. By taking into account inhibited diffusion and migration of chemical products that the porous film causes, its sterically inhibiting effect has for the first time been quantitatively interpreted. The porous corrosion product can most closely resemble the lid experimentally observed above local corrosion attacks, which leads to an even more diminished surface activity in electrochemical reactions compared with the deposition of only compact corrosion products on the anode surface.

        The kinetic model has resulted in a significantly deeper insight into the mechanism of micro-galvanic corrosion of the investigated system. The simulation has been shown to predict the time-dependent geometric changes of the anodically dissolved aluminum surface as well as the flow and distribution of generated chemical products. Contrary to the widely accepted perception that Al(OH)3 is not stable in the occluded acidified electrolyte environment, the calculations predict a higher local pH in the occluded electrolyte. This means that insoluble Al(OH)3 can be deposited on the electrode surface, the blocking effect of which may lead to a termination of the micro-galvanic corrosion. If the ring width is initially 0.5 μm or less, transport of OH- ions from the cathode surface to the occluded electrolyte environment is limited, leading to a local acidification within the occluded dissolving volume. At a given anodic ring width, an increased radius of the cathodic particle instead leads to an increased anodic dissolution rate by formation of a larger area for the cathode reaction. Variation of the chemical parameters in the electrolyte also shows that the simulated micro-galvanic corrosion rate of aluminum has a minimum at pH = 6. Both more acidic and more alkaline conditions result in an elevated anodic dissolution of aluminum. When pH ≤ 4, the deposition of Al(OH)3  becomes negligible, and the micro-galvanic corrosion will continue uninterrupted, completely in accordance with experimental data.

  • 412.
    Yin, Litao
    et al.
    Univ Sci & Technol Beijing, Natl Ctr Mat Serv Safety, Beijing 100083, Peoples R China.;KTH Royal Inst Technol, Sch Engn Sci Chem Biotechnol & Hlth, Dept Chem, Div Surface & Corros Sci, SE-10044 Stockholm, Sweden..
    Pan, Jinshan
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap.
    Leygraf, Christofer
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap.
    Jin, Ying
    Univ Sci & Technol Beijing, Natl Ctr Mat Serv Safety, Beijing 100083, Peoples R China..
    Experimental and Simulation Investigations of Copper Reduction Mechanism with and without Addition of SPS2018Inngår i: Journal of the Electrochemical Society, ISSN 0013-4651, E-ISSN 1945-7111, Vol. 165, nr 13, s. D604-D611Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Rotating disk electrode and rotating ring-disk electrode were used to investigate the mechanism of copper reduction and the influence of convection on the effect of Bis-3-sodiumsulfopropyl disulfide (SPS), a widely used accelerator in copper via-filling and copper foil manufacturing. The experimental results show that the commonly accepted single electron transfer for copper reduction is dominating in the low overpotential range, whereas the double electron transfer is also involved in the high overpotential range. SPS was found to exhibit a weak inhibition effect even with Cl- ion in the solution under strong convection, and generate more intermediates in the solution with both Cl- ion and SPS than with Cl- ion alone. Based on the experimental observations, a reaction model for copper reduction considering competition between the single electron transfer and the double electron transfer, as well as desorption and runoff of generated Cu+-containing intermediates, was proposed and used for finite element method modeling. The simulation results enable quantitative description of the proportion of the two charge transfer reactions and the runoff of the intermediates, providing guidelines for selecting the additives and plating conditions in industrial manufacturing. 

  • 413.
    Yoder, Mikayla A.
    et al.
    Univ Illinois, Sch Chem Sci, Urbana, IL 61801 USA.;Univ Illinois, Frederick Seitz Mat Res Lab, Urbana, IL 61801 USA.;Univ Illinois, Dept Mat Sci & Engn, Urbana, IL 61801 USA..
    Yan, Zheng
    Univ Missouri, Dept Chem Engn, Columbia, MO 65211 USA.;Univ Missouri, Dept Mech & Aerosp Engn, Columbia, MO 65211 USA..
    Han, Mengdi
    Northwestern Univ, Ctr Biointegrated Elect, Evanston, IL 60208 USA..
    Rogers, John A.
    Univ Illinois, Frederick Seitz Mat Res Lab, Urbana, IL 61801 USA.;Univ Illinois, Dept Mat Sci & Engn, Urbana, IL 61801 USA.;Northwestern Univ, Ctr Biointegrated Elect, Evanston, IL 60208 USA..
    Nuzzo, Ralph G.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap.
    Semiconductor Nanomembrane Materials for High-Performance Soft Electronic Devices2018Inngår i: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 140, nr 29, s. 9001-9019Artikkel, forskningsoversikt (Fagfellevurdert)
    Abstract [en]

    The development of methods to synthesize and physically manipulate extremely thin, single-crystalline inorganic semiconductor materials, so-called nano membranes, has led to an almost explosive growth of research worldwide into uniquely enabled opportunities for their use in new "soft" and other unconventional form factors for high-performance electronics. The unique properties that nanomembranes afford, such as their flexibility and lightweight characteristics, allow them to be integrated into electronic and optoelectronic devices that, in turn, adopt these unique attributes. For example, nanomembrane devices are able to make conformal contact to curvilinear surfaces and manipulate strain to induce the self-assembly of various 3D nano/micro device architectures. Further, thin semiconductor materials (e.g., Si-nanomembranes, transition metal dichalcogenides, and phosphorene) are subject to the impacts of quantum and other size-dependent effects that in turn enable the manipulation of their bandgaps and the properties of electronic and optoelectronic devices fabricated from them. In this Perspective, nanomembrane synthesis techniques and exemplary applications of their use are examined. We specifically describe nanomembrane chemistry exploiting high-performance materials, along with precise/high-throughput techniques for their manipulation that exemplify their growing capacities to shape outcomes in technology. Prominent challenges in the chemistry of these materials are presented along with future directions that might guide the development of next generation nanomembrane-based devices.

  • 414.
    Ytterberg, A. Jimmy
    et al.
    Karolinska Inst, Dept Med Biochem & Biophys, Chem Div 1, Stockholm, Sweden.;Karolinska Inst, Dept Med, Rheumatol Unit, Stockholm, Sweden.;Swedish Orphan Biovitrum AB Publ, Stockholm, Sweden..
    Zubarev, Roman A.
    Karolinska Inst, Dept Med Biochem & Biophys, Chem Div 1, Stockholm, Sweden..
    Baumgarten, Thomas
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Glykovetenskap.
    Posttranslational Targeting of a Recombinant Protein Promotes Its Efficient Secretion into the Escherichia coli Periplasm2019Inngår i: Applied and Environmental Microbiology, ISSN 0099-2240, E-ISSN 1098-5336, Vol. 85, nr 13, artikkel-id UNSP e00671Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Many recombinant proteins that are produced in Escherichia coli have to be targeted to the periplasm to be functional. N-terminal signal peptides can be used to direct recombinant proteins to the membrane-embedded Sec translocon, a multiprotein complex that translocates proteins across the membrane into the periplasm. We have recently shown that the cotranslational targeting of the single-chain variable antibody fragment BL1 saturates the capacity of the Sec translocon leading to impaired translocation of secretory proteins and protein misfolding/aggregation in the cytoplasm. In turn, protein production yields and biomass formation were low. Here, we study the consequences of targeting BL1 posttranslationally to the Sec translocon. Notably, the posttranslational targeting of BL1 does not saturate the Sec translocon capacity, and both biomass formation and protein production yields are increased. Analyzing the proteome of cells producing the posttranslationally targeted BL1 indicates that the decreased synthesis of endogenous secretory and membrane proteins prevents a saturation of the Sec translocon capacity. Furthermore, in these cells, highly abundant chaperones and proteases can clear misfolded/aggregated proteins from the cytoplasm, thereby improving the fitness of these cells. Thus, the posttranslational targeting of BL1 enables its efficient production in the periplasm due to a favorable adaptation of the E. coli proteome. We envisage that our observations can be used to engineer E. coli for the improved production of recombinant secretory proteins. IMPORTANCE The bacterium Escherichia coli is widely used to produce recombinant proteins. To fold properly, many recombinant proteins have to be targeted to the E. coli periplasm, but so far the impact of the targeting pathway of a recombinant protein to the periplasm has not been extensively investigated. Here, we show that the targeting pathway of a recombinant antibody fragment has a tremendous impact on cell physiology, ultimately affecting protein production yields in the periplasm and biomass formation. This indicates that studying the targeting and secretion of proteins into the periplasm could be used to design strategies to improve recombinant protein production yields.

  • 415.
    Zhang, Biaobiao
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi.
    Li, Yuanyuan
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Valvo, M.
    Fan, Lizhou
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi.
    Daniel, Quentin
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi.
    Zhang, Peili
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi.
    Wang, Linqin
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi.
    Sun, Licheng
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi.
    Electrocatalytic Water Oxidation Promoted by 3 D Nanoarchitectured Turbostratic Δ-MnOx on Carbon Nanotubes2017Inngår i: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 10, nr 22, s. 4472-4478Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The development of manganese-based water oxidation electrocatalysts is desirable for the production of solar fuels, as manganese is earth-abundant, inexpensive, non-toxic, and has been employed by the Photosystem II in nature for a billion years. Herein, we directly constructed a 3 D nanoarchitectured turbostratic δ-MnOx on carbon nanotube-modified nickel foam (MnOx/CNT/NF) by electrodeposition and a subsequent annealing process. The MnOx/CNT/NF electrode gives a benchmark catalytic current density (10 mA cm−2) at an overpotential (η) of 270 mV under alkaline conditions. A steady current density of 19 mA cm−2 is obtained during electrolysis at 1.53 V for 1.0 h. To the best of our knowledge, this work represents the most efficient manganese-oxide-based water oxidation electrode and demonstrates that manganese oxides, as a structural and functional model of oxygen-evolving complex (OEC) in Photosystem II, can also become comparable to those of most Ni- and Co-based catalysts.

  • 416.
    Zhang, Biaobiao
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi.
    Sun, Licheng
    KTH, Skolan för kemivetenskap (CHE), Centra, Molekylär elektronik, CMD. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Organisk kemi. Dalian Univ Technol.
    Across the Board: Licheng Sun on the Mechanism of O-O Bond Formation in Photosystem II2019Inngår i: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 12, nr 14, s. 3401-3404Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this series of articles, the board members of ChemSusChem discuss recent research articles that they consider of exceptional quality and importance for sustainability. This entry features Prof. L. Sun, who proposes a special mechanism for O-O bond formation in photosystem II with involvement of an Mn-VII-oxo species induced by charge- and structural rearrangements. In this viewpoint, Proton transfer is involved in changes of the first coordination spheres around the Mn-VII-oxo site on the dangling Mn4 with de- and re-coordination of carboxylates (Glu333 and Asp170).

  • 417.
    Zhang, Biaobiao
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi.
    Sun, Licheng
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi.
    Artificial photosynthesis: opportunities and challenges of molecular catalysts2019Inngår i: Chemical Society Reviews, ISSN 0306-0012, E-ISSN 1460-4744, Vol. 48, nr 7, s. 2216-2264Artikkel, forskningsoversikt (Fagfellevurdert)
    Abstract [en]

    Molecular catalysis plays an essential role in both natural and artificial photosynthesis (AP). However, the field of molecular catalysis for AP has gradually declined in recent years because of doubt about the long-term stability of molecular-catalyst-based devices. This review summarizes the development history of molecular-catalyst-based AP, including the fundamentals of AP, molecular catalysts for water oxidation, proton reduction and CO2 reduction, and molecular-catalyst-based AP devices, and it provides an analysis of the advantages, challenges, and stability of molecular catalysts. With this review, we aim to highlight the following points: (i) an investigation on molecular catalysis is one of the most promising ways to obtain atom-efficient catalysts with outstanding intrinsic activities; (ii) effective heterogenization of molecular catalysts is currently the primary challenge for the application of molecular catalysis in AP devices; (iii) development of molecular catalysts is a promising way to solve the problems of catalysis involved in practical solar fuel production. In molecular-catalysis-based AP, much has been attained, but more challenges remain with regard to long-term stability and heterogenization techniques.

  • 418.
    Zhang, Biaobiao
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi.
    Sun, Licheng
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi.
    Ru-bda: Unique Molecular Water-Oxidation Catalysts with Distortion Induced Open Site and Negatively Charged Ligands2019Inngår i: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 141, nr 14, s. 5565-5580Artikkel, forskningsoversikt (Fagfellevurdert)
    Abstract [en]

    A water-oxidation catalyst with high intrinsic activity is the foundation for developing any type of water-splitting device. To celebrate its 10 years anniversary, in this Perspective we focus on the state-of-the-art molecular water-oxidation catalysts (MWOCs), the Ru-bda series (bda = 2,2'-bipyridine-6,6'-dicarboxylate), to offer strategies for the design and synthesis of more advanced MWOCs. The O-O bond formation mechanisms, derivatives, applications, and reasons behind the outstanding catalytic activities of Ru-bda catalysts are summarized and discussed. The excellent performance of the Ru-bda catalyst is owing to its unique structural features: the distortion induced 7-coordination and the carboxylate ligands with coordination flexibility, proton transfer function as well as small steric hindrance. Inspired by the Ru-bda catalysts, we emphasize that the introduction of negatively charged groups, such as the carboxylate group, into ligands is an effective strategy to lower the onset potential of MWOCs. Moreover, distortion of the regular configuration of a transition metal complex by ligand design to generate a wide open site as the catalytic site for binding the substrate as an extra-coordination is proposed as a new concept for the design of efficient molecular catalysts. These inspirations can be expected to play a great role in not only water oxidation catalysis but also other small molecule activation and conversion reactions involving artificial photosynthesis, such as CO2 reduction and N-2 fixation reactions.

  • 419.
    Zhang, Biaobiao
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi.
    Sun, Licheng
    KTH, Skolan för kemivetenskap (CHE), Centra, Molekylär elektronik, CMD. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi.
    Why nature chose the Mn4CaO5 cluster as water-splitting catalyst in photosystem II: a new hypothesis for the mechanism of O-O bond formation2018Inngår i: Dalton Transactions, ISSN 1477-9226, E-ISSN 1477-9234, Vol. 47, nr 41, s. 14381-14387Artikkel, forskningsoversikt (Fagfellevurdert)
    Abstract [en]

    Resolving the questions, namely, the selection of Mn by nature to build the oxygen-evolving complex (OEC) and the presence of a cubic Mn3CaO4 structure in OEC coupled with an additional dangling Mn (Mn4) via mu-O atom are not only important to uncover the secret of water oxidation in nature, but also essential to achieve a blueprint for developing advanced water-oxidation catalysts for artificial photosynthesis. Based on the important experimental results reported so far in the literature and on our own findings, we propose a new hypothesis for the water oxidation mechanism in OEC. In this new hypothesis, we propose for the first time, a complete catalytic cycle involving a charge-rearrangement-induced Mn-VII-dioxo species on the dangling Mn4 during the S-3 -> S-4 transition. Moreover, the O-O bond is formed within this Mn-VII-dioxo site, which is totally different from that discussed in other existing proposals.

  • 420.
    Zhang, Bo
    et al.
    Dalian Univ Technol, Inst Energy Sci & Technol, DUT KTH Joint Educ & Res Ctr Mol Devices, State Key Lab Fine Chem, Dalian 116024, Peoples R China..
    Hou, Jungang
    Dalian Univ Technol, Inst Energy Sci & Technol, DUT KTH Joint Educ & Res Ctr Mol Devices, State Key Lab Fine Chem, Dalian 116024, Peoples R China..
    Wu, Yunzhen
    Dalian Univ Technol, Inst Energy Sci & Technol, DUT KTH Joint Educ & Res Ctr Mol Devices, State Key Lab Fine Chem, Dalian 116024, Peoples R China..
    Cao, Shuyan
    Dalian Univ Technol, Inst Energy Sci & Technol, DUT KTH Joint Educ & Res Ctr Mol Devices, State Key Lab Fine Chem, Dalian 116024, Peoples R China..
    Li, Zhuwei
    Dalian Univ Technol, Inst Energy Sci & Technol, DUT KTH Joint Educ & Res Ctr Mol Devices, State Key Lab Fine Chem, Dalian 116024, Peoples R China..
    Nie, Xiaowa
    Dalian Univ Technol, Inst Energy Sci & Technol, DUT KTH Joint Educ & Res Ctr Mol Devices, State Key Lab Fine Chem, Dalian 116024, Peoples R China..
    Gao, Zhanming
    Dalian Univ Technol, Inst Energy Sci & Technol, DUT KTH Joint Educ & Res Ctr Mol Devices, State Key Lab Fine Chem, Dalian 116024, Peoples R China..
    Sun, Licheng
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi. Dalian Univ Technol, Inst Energy Sci & Technol, DUT .
    Tailoring Active Sites in Mesoporous Defect-Rich NC/V-o-WON Heterostructure Array for Superior Electrocatalytic Hydrogen Evolution2019Inngår i: ADVANCED ENERGY MATERIALS, ISSN 1614-6832, Vol. 9, nr 12, artikkel-id 1803693Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Tailoring active sites in earth-abundant non-noble metal electrocatalysts are required toward widespread applications in sustainable energy fields. Herein, an integrated mesoporous heterostructure array is reported by a hydrogenation/nitridation-induced in situ growth strategy. Highly conductive oxygen-vacancies-rich tungsten oxynitride (V-o-WON) nanorod array acts as the backbone encapsulated by ultrathin nitrogen-doped carbon (NC) nanolayers, forming high-quality shell/core NC/V-o-WON heterostructures. Density functional theory calculations reveal that defect-rich heterostructure arrays not only enhance the conductivity and modulate electronic structure but also promote the adsorption and dissociation of reactants and offer substantial potential sites. As expected, porous NC/V-o-WON array exhibits a small overpotential of 16 mV at the current density of 10 mA cm(-2) and a low Tafel slope of 33 mV per decade in alkaline media, accompanied by negligible loss upon a large current density over 100 h. Benefiting from outstanding electrocatalytic hydrogen evolution reaction performance and stability, this defective heterostructure could serve as a prominent alternative electrocatalyst for renewable energy applications.

  • 421.
    Zhang, Fan
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap.
    Chen, Chengdong
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap.
    Hou, R.
    Li, Jing
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap.
    Cao, Yanhui
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap.
    Dong, S.
    Lin, C.
    Pan, Jinshan
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap.
    Investigation and application of mussel adhesive protein nanocomposite film-forming inhibitor for reinforced concrete engineering2019Inngår i: Corrosion Science, ISSN 0010-938X, E-ISSN 1879-0496, Vol. 153, s. 333-340Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A mussel adhesive protein based nanocomposite thin film was produced to be applied as surface pre-treatment or primer on rebars of reinforced concrete. The film deposition and drying processes were investigated to enhance the corrosion protection, and facilitate large-scale industrial applications. The morphology, chemical composition and microstructure of the film were characterised with SEM, EDS, Micro-IR and AFM techniques. EIS results suggested the film provides excellent and increased corrosion protection for the carbon steel in mild and extreme concrete pore solutions. In-situ AFM results demonstrated the self-healing ability of the film to the pitting corrosion.

  • 422.
    Zhang, Fan
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap.
    Pan, Jinshan
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap.
    Recent Development of Corrosion Protection Strategy Based on Mussel Adhesive Protein2019Inngår i: FRONTIERS IN MATERIALS, ISSN 2296-8016, Vol. 6, artikkel-id 207Artikkel, forskningsoversikt (Fagfellevurdert)
    Abstract [en]

    Many of traditional anti-corrosion approaches using chromate are effective but hazardous to natural environment and human health, so development of green and effective alternatives is desirable. One of the mussel adhesive proteins derived from mussel byssus presents extraordinary adhesion to steel surface and exhibits film-forming and corrosion inhibition properties. Novel strategies for enhancing the corrosion inhibition of steel by the protein have been demonstrated recently. The protein together with ceria nanoparticles presents a great potential for the development of new corrosion inhibitors and thin films that are "green" and "effective," and have "smart" protection properties.

  • 423.
    Zhang, Fuguo
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Organisk kemi.
    Cong, Jiayan
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Tillämpad fysikalisk kemi.
    Li, Yuanyuan
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center.
    Bergstrand, Jan
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Teoretisk kemi och biologi.
    Liu, Haichun
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik.
    Cai, Bin
    State Key Laboratory of Fine Chemicals, Dalian University of Technology (DUT).
    Hajian, Alireza
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center.
    Yao, Zhaoyang
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Organisk kemi.
    Wang, Linqin
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Organisk kemi.
    Hao, Yan
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Tillämpad fysikalisk kemi.
    Yang, Xichuan
    State Key Laboratory of Fine Chemicals, Dalian University of Technology (DUT).
    Gardner, James M.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Tillämpad fysikalisk kemi.
    Ågren, Hans
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Teoretisk kemi och biologi.
    Widengren, Jerker
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Teoretisk kemi och biologi. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center.
    Kloo, Lars
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Tillämpad fysikalisk kemi.
    Sun, Licheng
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi. State Key Laboratory of Fine Chemicals, Dalian University of Technology (DUT).
    A facile route to grain morphology controllable perovskite thin films towards highly efficient perovskite solar cells2018Inngår i: Nano Energy, ISSN 2211-2855, E-ISSN 2211-3282, Vol. 53, s. 405-414Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Perovskite photovoltaics have recently attracted extensive attention due to their unprecedented high power conversion efficiencies (PCEs) in combination with primitive manufacturing conditions. However, the inherent polycrystalline nature of perovskite films renders an exceptional density of structural defects, especially at the grain boundaries (GBs) and film surfaces, representing a key challenge that impedes the further performance improvement of perovskite solar cells (PSCs) and large solar module ambitions towards commercialization. Here, a novel strategy is presented utilizing a simple ethylammonium chloride (EACl) additive in combination with a facile solvent bathing approach to achieve high quality methyammonium lead iodide (MAPbI3) films. Well-oriented, micron-sized grains were observed, which contribute to an extended carrier lifetime and reduced trap density. Further investigations unraveled the distinctively prominent effects of EACl in modulating the perovskite film quality. The EACl was found to promote the perovskite grain growing without undergoing the formation of intermediate phases. Moreover, the EACl was also revealed to deplete at relative low temperature to enhance the film quality without compromising the beneficial bandgap for solar cell applications. This new strategy boosts the power conversion efficiency (PCE) to 20.9% and 19.0% for devices with effective areas of 0.126 cm2 and 1.020 cm2, respectively, with negligible current hysteresis and enhanced stability. Besides, perovskite films with a size of 10 × 10 cm2, and an assembled 16 cm2(5 × 5 cm2 module) perovskite solar module with a PCE of over 11% were constructed.

  • 424.
    Zhang, Jinbao
    et al.
    Monash Univ, Dept Mat Sci & Engn, Clayton, Vic 3800, Australia..
    Daniel, Quentin
    KTH, Skolan för kemivetenskap (CHE), Centra, Molekylär elektronik, CMD. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Organisk kemi.
    Zhang, Tian
    Monash Univ, Dept Mat Sci & Engn, Clayton, Vic 3800, Australia..
    Wen, Xiaoming
    Swinburne Univ Technol, Ctr Microphoton, Melbourne, Vic 3122, Australia..
    Xu, Bo
    Uppsala Univ, Phys Chem, Dept Chem, Angstrom Lab, Box 523, S-75120 Uppsala, Sweden..
    Sun, Licheng
    KTH, Skolan för kemivetenskap (CHE), Centra, Molekylär elektronik, CMD. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Organisk kemi. Dalian Univ Technol, State Key Lab Fine Chem, DUT KTH Joint Educ & Res Ctr Mol Devices, Dalian 116012, Peoples R China..
    Bach, Udo
    Monash Univ, Dept Chem Engn, Clayton, Vic 3800, Australia.;CSIRO Mfg, Clayton, Vic 3168, Australia.;Melbourne Ctr Nanofabricat, Clayton, Vic 3800, Australia..
    Cheng, Yi-Bing
    Monash Univ, Dept Mat Sci & Engn, Clayton, Vic 3800, Australia.;Wuhan Univ Technol, State Key Lab Silicate Mat Architectures, Wuhan 430070, Hubei, Peoples R China..
    Chemical Dopant Engineering in Hole Transport Layers for Efficient Perovskite Solar Cells: Insight into the Interfacial Recombination2018Inngår i: ACS Nano, ISSN 1936-0851, E-ISSN 1936-086X, Vol. 12, nr 10, s. 10452-10462Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Chemical doping of organic semiconductors has been recognized as an effective way to enhance the electrical conductivity. In perovskite solar cells (PSCs), various types of dopants have been developed for organic hole transport materials (HTMs); however, the knowledge of the basic requirements for being efficient dopants as well as the comprehensive roles of the dopants in PSCs has not been clearly revealed. Here, three copper-based complexes with controlled redox activities are applied as dopants in PSCs, and it is found that the oxidative reactivity of dopants presents substantial impacts on conductivity, charge dynamics, and solar cell performance. A significant improvement of open- circuit voltage (V-oc) by more than 100 mV and an increase of power conversion efficiency from 13.2 to 19.3% have been achieved by tuning the doping level of the HTM. The observed large variation of V-oc for three dopants reveals their different recombination kinetics at the perovskite/HTM interfaces and suggests a model of an interfacial recombination mechanism. We also suggest that the dopants in HTMs can also affect the charge recombination kinetics as well as the solar cell performance. Based on these findings, a strategy is proposed to physically passivate the electron- hole recombination by inserting an ultrathin Al2O3 insulating layer between the perovskite and the HTM. This strategy contributes a significant enhancement of the power conversion efficiency and environmental stability, indicating that dopant engineering is one crucial way to further improve the performance of PSCs.

  • 425.
    Zhang, Li
    et al.
    Dalian Univ Technol, DUT KTH Joint Educ & Res Ctr Mol Devices, Inst Artificial Photosynth, State Key Lab Fine Chem, 2 Linggong Rd, Dalian 116024, Peoples R China..
    Yang, Xichuan
    Dalian Univ Technol, DUT KTH Joint Educ & Res Ctr Mol Devices, Inst Artificial Photosynth, State Key Lab Fine Chem, 2 Linggong Rd, Dalian 116024, Peoples R China..
    Wang, Weihan
    Dalian Univ Technol, DUT KTH Joint Educ & Res Ctr Mol Devices, Inst Artificial Photosynth, State Key Lab Fine Chem, 2 Linggong Rd, Dalian 116024, Peoples R China..
    Gurzadyan, Gagik G.
    Dalian Univ Technol, DUT KTH Joint Educ & Res Ctr Mol Devices, Inst Artificial Photosynth, State Key Lab Fine Chem, 2 Linggong Rd, Dalian 116024, Peoples R China..
    Li, Jiajia
    Dalian Univ Technol, DUT KTH Joint Educ & Res Ctr Mol Devices, Inst Artificial Photosynth, State Key Lab Fine Chem, 2 Linggong Rd, Dalian 116024, Peoples R China..
    Li, Xiaoxin
    Dalian Univ Technol, DUT KTH Joint Educ & Res Ctr Mol Devices, Inst Artificial Photosynth, State Key Lab Fine Chem, 2 Linggong Rd, Dalian 116024, Peoples R China..
    An, Jincheng
    Dalian Univ Technol, DUT KTH Joint Educ & Res Ctr Mol Devices, Inst Artificial Photosynth, State Key Lab Fine Chem, 2 Linggong Rd, Dalian 116024, Peoples R China..
    Yu, Ze
    Dalian Univ Technol, DUT KTH Joint Educ & Res Ctr Mol Devices, Inst Artificial Photosynth, State Key Lab Fine Chem, 2 Linggong Rd, Dalian 116024, Peoples R China..
    Wang, Haoxin
    Dalian Univ Technol, DUT KTH Joint Educ & Res Ctr Mol Devices, Inst Artificial Photosynth, State Key Lab Fine Chem, 2 Linggong Rd, Dalian 116024, Peoples R China..
    Cai, Bin
    Dalian Univ Technol, DUT KTH Joint Educ & Res Ctr Mol Devices, Inst Artificial Photosynth, State Key Lab Fine Chem, 2 Linggong Rd, Dalian 116024, Peoples R China..
    Hagfeldt, Anders
    Ecole Polytech Fed Lausanne, Lab Photomol Sci, Inst Chem Sci & Engn, CH-1015 Lausanne, Switzerland..
    Sun, Licheng
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Organisk kemi. Dalian Univ Technol, DUT KTH Joint Educ & Res Ctr Mol Devices, Inst Artificial Photosynth, State Key Lab Fine Chem, 2 Linggong Rd, Dalian 116024, Peoples R China.
    13.6% Efficient Organic Dye-Sensitized Solar Cells by Minimizing Energy Losses of the Excited State2019Inngår i: ACS ENERGY LETTERS, ISSN 2380-8195, Vol. 4, nr 4, s. 943-951Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The electron-injection energy losses of dye-sensitized solar cells (DSSCs) are among the fundamental problems hindering their successful breakthrough application. Two triazatruxene (TAT)-based sensitizers, with one containing a flexible Z-type double bond and another a rigid single bond, coded as ZL001 and ZL003, respectively, have been synthesized and applied in DSSCs to probe the energy losses in the process of electron injection. Using time-resolved laser spectroscopic techniques in the kinetic study, ZL003 with the rigid single bond promotes much faster electron injection into the conductive band of TiO2 especially in the locally excited state (hot injection), which leads to higher electron density in TiO2 and a higher V-oc. The devices based on ZL003 exhibited a champion power conversion efficiency (PCE) of 13.6% with V-oc = 956 mV, J(sc) = 20.73 mA cm(-2), and FF = 68.5%, which are among the highest recorded results to date on single dye-sensitized DSSCs. An independent certified PCE of 12.4% has been obtained for devices based on ZL003.

  • 426.
    Zhang, Liang
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Industriell bioteknologi. VINNOVA Competence Ctr Adv Bioprod Continuous Pro, AdBIOPRO, Stockholm, Sweden..
    Castan, Andreas
    GE Healthcare Biosci AB, Bjorkgatan 30, S-75184 Uppsala, Sweden..
    Stevenson, Joanne
    Cobra Biol AB, Stockholm, Sweden..
    Chatzissavidou, Nathalie
    Cobra Biol AB, Stockholm, Sweden..
    Vilaplana, Francisco
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Glykovetenskap.
    Chotteau, Veronique
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Industriell bioteknologi. VINNOVA Competence Ctr Adv Bioprod Continuous Pro, AdBIOPRO, Stockholm, Sweden..
    Combined effects of glycosylation precursors and lactate on the glycoprofile of IgG produced by CHO cells2019Inngår i: Journal of Biotechnology, ISSN 0168-1656, E-ISSN 1873-4863, Vol. 289, s. 71-79Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The glycosylation profile of therapeutic monoclonal antibodies (mAbs) is a crucial quality parameter for industrial Immunoglobulin G (IgG) production. Several alternative carbon sources, which function as glycosylation precursors, have been reported to impact the glycosylation pattern. Since the cells give priority to glucose uptake, the presence of this substrate can lower the effects of alternative sugars on the glycosylation. In order to get a better understanding of the influence of alternative sugars on the glycosylation and to investigate how they impact each other, combinations of mannose, fructose, galactose and fucose were fed to Chinese hamster ovary (CHO) cells in batch culture when the glucose became depleted and the lactate, accumulated in the culture, was used as carbon source. Feeding with a feed containing mannose or glucose decreased by 3-7% the percentage of high mannose glycans compared to a feed without mannose or glucose. Feeding with a feed containing galactose led to 8-20% increase of monogalactoglycans (G1) glycans and 2-6% rise of digalactoglycans (G2) glycans compared to feeding without galactose or glucose. The cells fed with fucose exhibited a significantly higher concentration of intracellular GDP-Fucose. This work indicates that a feeding strategy based on non-glucose sugars and potentially lactate, could be adopted to obtain a targeted glycosylation profile.

  • 427.
    Zhang, Peili
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi.
    Li, L.
    Nordlund, D.
    Chen, Hong
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi.
    Fan, Lizhou
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi.
    Zhang, Biaobiao
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi.
    Sheng, Xia
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Organisk kemi.
    Daniel, Quentin
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi.
    Sun, Licheng
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Organisk kemi.
    Dendritic core-shell nickel-iron-copper metal/metal oxide electrode for efficient electrocatalytic water oxidation2018Inngår i: Nature Communications, ISSN 2041-1723, E-ISSN 2041-1723, Vol. 9, nr 1, artikkel-id 381Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Electrochemical water splitting requires efficient water oxidation catalysts to accelerate the sluggish kinetics of water oxidation reaction. Here, we report a promisingly dendritic core-shell nickel-iron-copper metal/metal oxide electrode, prepared via dealloying with an electrodeposited nickel-iron-copper alloy as a precursor, as the catalyst for water oxidation. The as-prepared core-shell nickel-iron-copper electrode is characterized with porous oxide shells and metallic cores. This tri-metal-based core-shell nickel-iron-copper electrode exhibits a remarkable activity toward water oxidation in alkaline medium with an overpotential of only 180 mV at a current density of 10 mA cm-2. The core-shell NiFeCu electrode exhibits pH-dependent oxygen evolution reaction activity on the reversible hydrogen electrode scale, suggesting that non-concerted proton-electron transfers participate in catalyzing the oxygen evolution reaction. To the best of our knowledge, the as-fabricated core-shell nickel-iron-copper is one of the most promising oxygen evolution catalysts.

  • 428.
    Zhang, Peili
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi. State Key Laboratory of Fine Chemicals, Institute of Artificial Photosynthesis, DUT-KTH Joint Education and Research Centre on Molecular Devices, Dalian University of Technology, Dalian, 116024, China.
    Sheng, Xia
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Organisk kemi. State Key Laboratory of Fine Chemicals, Institute of Artificial Photosynthesis, DUT-KTH Joint Education and Research Centre on Molecular Devices, Dalian University of Technology, Dalian, 116024, China.
    Chen, Xiaoyu
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Teoretisk kemi och biologi.
    Fang, Zhiyong
    Jiang, Jian
    Wang, Mei
    Li, Fusheng
    Fan, Lizhou
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi.
    Ren, Yansong
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi.
    Zhang, Biaobiao
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi.
    Timmer, Brian J. J.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Organisk kemi.
    Ahlquist, Mårten S. G.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Teoretisk kemi och biologi.
    Sun, Licheng
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Organisk kemi. State Key Laboratory of Fine Chemicals, Institute of Artificial Photosynthesis, DUT-KTH Joint Education and Research Centre on Molecular Devices, Dalian University of Technology, Dalian, 116024, China.
    Paired Electrocatalytic Oxygenation and Hydrogenation of Organic Substrates with Water as the Oxygen and Hydrogen Source2019Inngår i: Angewandte Chemie International Edition, ISSN 1433-7851, E-ISSN 1521-3773, Vol. 58, nr 27, s. 9155-9159Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The use of water as an oxygen and hydrogen source for the paired oxygenation and hydrogenation of organic substrates to produce valuable chemicals is of utmost importance as a means of establishing green chemical syntheses. Inspired by the active Ni3+ intermediates involved in electro-catalytic water oxidation by nickel-based materials, we prepared NiBx as a catalyst and used water as the oxygen source for the oxygenation of various organic compounds. NiBx was further employed as both an anode and a cathode in a paired electrosynthesis cell for the respective oxygenation and hydrogenation of organic compounds, with water as both the oxygen and hydrogen source. Conversion efficiency and selectivity of >= 99% were observed during the oxygenation of 5-hydroxy-methylfurfural to 2,5-furandicarboxylic acid and the simultaneous hydrogenation of p-nitrophenol to p-aminophenol. This paired electrosynthesis cell has also been coupled to a solar cell as a stand-alone reactor in response to sunlight.

  • 429.
    Zhang, Wei
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Tillämpad fysikalisk kemi.
    Hua, Yong
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Tillämpad fysikalisk kemi.
    Wang, Linqin
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Organisk kemi.
    Zhang, Biaobiao
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Organisk kemi.
    Li, Yuanyuan
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Liu, Peng
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Tillämpad fysikalisk kemi.
    Leandri, Valentina
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Tillämpad fysikalisk kemi.
    Guo, Yu
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Tillämpad fysikalisk kemi.
    Chen, Hong
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Organisk kemi.
    Gardner, James M.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Tillämpad fysikalisk kemi.
    Sun, Licheng
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Organisk kemi. Dalian Univ Technol DUT, DUT KTH Joint Res Ctr Mol Devices, State Key Lab Fine Chem, Dalian 116024, Peoples R China..
    Kloo, Lars
    The Central Role of Ligand Conjugation for Properties of Coordination Complexes as Hole-Transport Materials in Perovskite Solar Cells2019Inngår i: ACS APPLIED ENERGY MATERIALS, ISSN 2574-0962, Vol. 2, nr 9, s. 6768-6779Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Two zinc-based coordination complexes Y3 and Y4 have been synthesized and characterized, and their performance as hole-transport materials (HTMs) for perovskite solar cells (PSCs) has been investigated. The complex Y3 contains two separate ligands, and the molecular structure can be seen as a disconnected porphyrin ring. On the other hand, Y4 consists of a porphyrin core and therefore is a more extended conjugated system as compared to Y3. The optical and redox properties of the two different molecular complexes are comparable. However, the hole mobility and conductivity of Y4 as macroscopic material are remarkably higher than that of Y3. Furthermore, when employed as hole-transport materials in perovskite solar cells, cells containing Y4 show a power conversion efficiency (PCE) of 16.05%, comparable to the Spiro-OMeTAD-based solar cells with an efficiency around 17.08%. In contrast, solar cells based on Y3 show a negligible efficiency of about 0.01%. The difference in performance of Y3 and Y4 is analyzed and can be attributed to the difference in packing of the nonplanar and planar building blocks in the corresponding materials.

  • 430.
    Zhang, Wei
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Teoretisk kemi och biologi.
    Sadollahkhani, Azar
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Teoretisk kemi och biologi.
    Li, Yuanyuan
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Leandri, Valentina
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Tillämpad fysikalisk kemi.
    Gardner, James M.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Tillämpad fysikalisk kemi.
    Kloo, Lars
    KTH, Skolan för kemivetenskap (CHE), Centra, Molekylär elektronik, CMD.
    Mechanistic Insights from Functional Group Exchange Surface Passivation: A Combined Theoretical and Experimental Study2019Inngår i: ACS APPLIED ENERGY MATERIALS, ISSN 2574-0962, Vol. 2, nr 4, s. 2723-2733Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Four different functional groups including amino (-NH2), phosphine (-PH2), hydroxyl (-OH), and thiol (-SH) were combined with POSS (polyhedral oligomeric silsesquioxane) molecules to investigate how functional groups affect the surface passivation of POSS systems. Results from density-functional theory (DFT) calculations indicate that functional group amino (-NH2) with adsorption energy 86 (56) kJ mol(-1) is consistently better than that of thiol (-SH) with adsorption energy 68 (43) kJ mor(-1) for different passivation mechanisms. Theoretical studies on the analogous POSS-OH and POSS-PH2 systems show similar adsorption energies. Two of the systems were also investigated experimentally; aminopropyl isobutyl POSS (POSS-NH2) and mercaptopropyl isobutyl POSS (POSS-SH) were applied as passivation materials for MAPbI(3) (MA = methylammonium) perovskite and (FA)(0.85)(MA)(0.15)Pb(I-3)(0.85)(Br-3)(0)(.15)(FA = formamidinium) perovskite films. The same conclusion was drawn based on the results from contact angle studies, X-ray diffraction (XRD), and the stability of solar cells in ambient atmosphere, indicating the vital importance of choice of functional groups for passivation of the perovskite materials.

  • 431.
    Zhang, Xian
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap. Wuhan Univ Sci & Technol, State Key Lab Refractory Mat & Met, Hubei Prov Key Lab Syst Sci Met Proc, Int Res Inst Steel Technol, Wuhan 430081, Hubei, Peoples R China..
    Odnevall Wallinder, Inger
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap.
    Leygraf, Christopher
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap.
    Atmospheric corrosion of Zn-Al coatings in a simulated automotive environment2018Inngår i: Surface Engineering, ISSN 0267-0844, E-ISSN 1743-2944, Vol. 34, nr 9, s. 641-648Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Accelerated NVDA (VDA 233-102) tests were performed on bare Zn and Al sheets, Galfan coating (Zn-5 wt-% Al) and Galvalume coating (Zn-55 wt-% Al) on steel. ZnO, Zn(OH)(2) and Zn-5(OH)(8)Cl-2 center dot H2O were the main corrosion products identified on both bare Zn sheet and Galfan. AlOOH and Al(OH)(3) were preferentially formed on bare Al sheet and Galvalume. In addition, Zn-Al-containing corrosion products, Zn6Al2(OH)(16)CO3 center dot 4H(2)O and/or Zn2Al(OH)(6)Cl center dot 2H(2)O were identified on both Galfan and Galvalume. Corrosion products of Zn6Al2(OH)(16)CO3 center dot 4H(2)O with a platelet morphology were preferentially formed in the zinc-rich interdendritic regions of the Galvalume surface. Galfan revealed a similar corrosion behaviour as bare Zn sheet, whereas Galvalume exhibited similar behaviour as bare Al sheet. Deposition of chlorides highly influenced the corrosion of both Galvalume and Al rather than Galfan and Zn due to the rapid local damage of the compact native thin film of Al2O3.

  • 432.
    Zhang, Xiaoliang
    et al.
    Beihang Univ, Sch Mat Sci & Engn, Beijing 100191, Peoples R China..
    Cappel, Ute B.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Tillämpad fysikalisk kemi.
    Jia, Donglin
    Beihang Univ, Sch Mat Sci & Engn, Beijing 100191, Peoples R China..
    Zhou, Qisen
    Beihang Univ, Sch Mat Sci & Engn, Beijing 100191, Peoples R China..
    Du, Juan
    Beihang Univ, Sch Mat Sci & Engn, Beijing 100191, Peoples R China..
    Sloboda, Tamara
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Teoretisk kemi och biologi.
    Svanström, Sebastian
    Uppsala Univ, Dept Phys & Astron, Div Mol & Condensed Matter Phys, Box 516, SE-75120 Uppsala, Sweden..
    Johansson, Fredrik O. L.
    Uppsala Univ, Dept Phys & Astron, Div Mol & Condensed Matter Phys, Box 516, SE-75120 Uppsala, Sweden..
    Lindblad, Andreas
    Uppsala Univ, Dept Phys & Astron, Div Mol & Condensed Matter Phys, Box 516, SE-75120 Uppsala, Sweden..
    Giangrisostomi, Erika
    Helmholtz Zentrum Berlin GmbH, Inst Methods & Instrumentat Synchrotron Radiat Re, Albert Einstein Str 15, D-12489 Berlin, Germany..
    Ovsyannikov, Ruslan
    Helmholtz Zentrum Berlin GmbH, Inst Methods & Instrumentat Synchrotron Radiat Re, Albert Einstein Str 15, D-12489 Berlin, Germany..
    Liu, Jianhua
    Beihang Univ, Sch Mat Sci & Engn, Beijing 100191, Peoples R China..
    Rensmo, Håkan
    Uppsala Univ, Dept Phys & Astron, Div Mol & Condensed Matter Phys, Box 516, SE-75120 Uppsala, Sweden..
    Gardner, James M.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Tillämpad fysikalisk kemi.
    Johansson, Erik M. J.
    Uppsala Univ, Phys Chem, Dept Chem Angstrom, S-75120 Uppsala, Sweden..
    Probing and Controlling Surface Passivation of PbS Quantum Dot Solid for Improved Performance of Infrared Absorbing Solar Cells2019Inngår i: Chemistry of Materials, ISSN 0897-4756, E-ISSN 1520-5002, Vol. 31, nr 11, s. 4081-4091Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Surface properties of colloidal quantum dots (CQDs) are critical for the transportation and recombination of the photoinduced charge carrier in CQD solar cells, therefore dominating the photovoltaic performance. Herein, PbS CQD passivated using liquid-state ligand exchange (LSLX) and solid-state ligand exchange (SSLX) strategies are in detail investigated using photoelectron spectroscopy (PES), and solar cell devices are prepared to understand the link between the CQD surface properties and the solar cell function. PES using different energies in the soft and hard Xray regime is applied to study the surface and bulk properties of the CQDs, and the results show more effective surface passivation of the CQDs prepared with the LSLX strategy and less formation of lead-oxide. The CQD solar cells prepared with LSLX strategy show higher performance, and the photoelectric measurements suggest that the recombination of photoinduced charges is reduced for the solar cell prepared with the LSLX approach. Meanwhile, the fabricated solar cells exhibit good stability. This work provides important insights into how to fine-tune the CQD surface properties by improving the CQD passivation, and how this is linked to further improvements of the device photovoltaic performance.

  • 433.
    Zhang, Yang
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Energiprocesser.
    Xie, Sheng
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Organisk kemi.
    Yan, Mingdi
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Organisk kemi.
    Ramström, Olof
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Organisk kemi.
    Enzyme- and ruthenium-catalyzed dynamic kinetic resolution involving cascade alkoxycarbonylations for asymmetric synthesis of 5-Substituted N-Aryloxazolidinones2019Inngår i: Molecular Catalysis, ISSN 2468-8231, Vol. 470, s. 138-144Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    AAsymmetric synthesis of N-aryloxazolidinones via dynamic kinetic resolution was developed. A ruthenium-based catalyst was used in the racemization of beta-anilino alcohols, while Candida antarctica lipase B (CAL-B) was applied for two selective alkoxycarbonylations operating in cascade. Various N-aryloxazolidinone derivatives were obtained in high yields and good enantiopurities.

  • 434.
    Zhang, Yongfei
    et al.
    DUT, DUT KTH Joint Educ & Res Ctr Mol Devices, State Key Lab Fine Chem, Inst Artificial Photosynth, Dalian 116024, Peoples R China..
    Liang, Yongqi
    DUT, DUT KTH Joint Educ & Res Ctr Mol Devices, State Key Lab Fine Chem, Inst Artificial Photosynth, Dalian 116024, Peoples R China..
    Wang, Yajuan
    DUT, DUT KTH Joint Educ & Res Ctr Mol Devices, State Key Lab Fine Chem, Inst Artificial Photosynth, Dalian 116024, Peoples R China..
    Guo, Fengwan
    Peking Univ, Beijing Natl Lab Mol Sci, State Key Lab Struct Chem Unstable & Stable Speci, Coll Chem & Mol Engn, Beijing 100871, Peoples R China..
    Sun, Licheng
    KTH, Skolan för kemivetenskap (CHE), Centra, Molekylär elektronik, CMD. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi.
    Xu, Dongsheng
    Peking Univ, Beijing Natl Lab Mol Sci, State Key Lab Struct Chem Unstable & Stable Speci, Coll Chem & Mol Engn, Beijing 100871, Peoples R China..
    Planar FAPbBr(3) Solar Cells with Power Conversion Efficiency above 10%2018Inngår i: ACS ENERGY LETTERS, ISSN 2380-8195, Vol. 3, nr 8, s. 1808-1814Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Bromide-based hybrid perovskites are of particular interest not only due to the fact that they offer a way to go beyond the Shockley-Queisser limit via the tandem cell scheme but single junction devices of them can also achieve reasonably high efficiency with high stability for solar energy conversion. However, the highest power conversion efficiency achieved up to now for FAPbBr(3) single-junction solar cells is only 8.2%, which is far below the efficiency of-17% predicted from detailed balance analysis. Here, a two-step method (the intermolecule exchange pathway) was systematically optimized for the fabrication of high quality FAPbBr(3) films. A molecule of urea, structurally similar to formamidinium, is introduced as an additive to tune the intermolecular ion exchange procedure. SnO2 is introduced as an electron-selective contact to the planar structured FAPbBr(3) solar cells. As a result, a power conversion efficiency of 10.61% and a V-oc of 1.56 V are achieved with planar structured solar cells, both of which represent the highest value ever reported for FAPbBr(3) solar cells.

  • 435.
    Zhao, Ruikai
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi.
    Liu, Longcheng
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik.
    Zhao, Li
    Tianjin Univ, Minist Educ China, Key Lab Efficient Utilizat Low & Medium Grade Ene, Tianjin 300350, Peoples R China..
    Deng, Shuai
    Tianjin Univ, Minist Educ China, Key Lab Efficient Utilizat Low & Medium Grade Ene, Tianjin 300350, Peoples R China..
    Li, Shuangjun
    Tianjin Univ, Minist Educ China, Key Lab Efficient Utilizat Low & Medium Grade Ene, Tianjin 300350, Peoples R China..
    Zhang, Yue
    Tianjin Univ, Minist Educ China, Key Lab Efficient Utilizat Low & Medium Grade Ene, Tianjin 300350, Peoples R China..
    Li, Hailong
    Malardalen Univ, Sch Business Soc & Engn, SE-72123 Vasteras, Sweden..
    Techno-economic analysis of carbon capture from a coal-fired power plant integrating solar-assisted pressure-temperature swing adsorption (PTSA)2019Inngår i: Journal of Cleaner Production, ISSN 0959-6526, E-ISSN 1879-1786, Vol. 214, s. 440-451Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper presents a techno-economic study to seek the feasibility about the proposed system that integrating solar-assisted pressure-temperature swing adsorption (PTSA) into an 800MWe coal-fired power plant. Solar energy has the potential to supply thermal energy demand for carbon capture, which can avoid the energy consumption of the traditional method such as the steam extraction. The performance of the proposed system is largely affected by the climatic conditions and solar collector's types. The assessment criteria include carbon emission intensity (CEO, levelized cost of electricity (LCOE) and cost of CO2 avoidance (COA). By the parametric analysis, the results show that CEI of the novel system with solar thermal collectors is approximately 2g/kWh lower than that of the referenced power plant with CO2 adsorption capture. In addition, CEI of the novel system can be further decrease with the decline of desorption temperature, adsorption pressure and desorption pressure. For the sake of lower LCOE and COA, the prices of the power plant capacity, adsorbents and solar collectors should be reduced. Specifically, LCOE of the system with evacuated tube collector will be lower than that of the reference system with CO2 capture as the price of solar field is lower than 46.08 USD/m2.

  • 436.
    Zhao, Tao
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Organisk kemi.
    Ganji, Suresh
    Schiebe, Christian
    Bohman, Bjorn
    Weinstein, Philip
    Krokene, Paal
    Borg-Karlson, Anna-Karin
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Organisk kemi.
    Unelius, C. Rikard
    Convergent evolution of semiochemicals across Kingdoms: bark beetles and their fungal symbionts2019Inngår i: The ISME Journal, ISSN 1751-7362, E-ISSN 1751-7370, Vol. 13, nr 6, s. 1535-1545Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Convergent evolution of semiochemical use in organisms from different Kingdoms is a rarely described phenomenon. Tree-killing bark beetles vector numerous symbiotic blue-stain fungi that help the beetles colonize healthy trees. Here we show for the first time that some of these fungi are able to biosynthesize bicyclic ketals that are pheromones and other semiochemicals of bark beetles. Volatile emissions of five common bark beetle symbionts were investigated by gas chromatography-mass spectrometry. When grown on fresh Norway spruce bark the fungi emitted three well-known bark beetle aggregation pheromones and semiochemicals (exo-brevicomin, endo-brevicomin and trans-conophthorin) and two structurally related semiochemical candidates (exo-1,3-dimethyl-2,9-dioxabicyclo[3.3.1]nonane and endo-1,3-dimethyl-2,9-dioxabicyclo[3.3.1]nonane) that elicited electroantennogram responses in the spruce bark beetle Ips typographus. When grown on malt agar with C-13 D-Glucose, the fungus Grosmannia europhioides incorporated C-13 into exo-brevicomin and trans-conophthorin. The enantiomeric compositions of the fungus-produced ketals closely matched those previously reported from bark beetles. The production of structurally complex bark beetle pheromones by symbiotic fungi indicates cross-kingdom convergent evolution of signal use in this system. This signaling is susceptible to disruption, providing potential new targets for pest control in conifer forests and plantations.

  • 437.
    Zhao, Weijie
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap.
    Johnson, C. Magnus
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap.
    Nano Infrared Microscopy: Obtaining Chemical Information on the Nanoscale in Corrosion Studies2019Inngår i: Journal of the Electrochemical Society, ISSN 0013-4651, E-ISSN 1945-7111, Vol. 166, nr 11, s. C3456-C3460Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this perspective article, the novel technique "nano infrared microscopy" is introduced as a valuable tool in the field of corrosion science to obtain chemical information with a spatial resolution of around 10 nm. Accordingly, the resolution is well below the diffraction limit, in contrast to conventional vibrational microscopy techniques. Thus, studies of corrosion initiation, localized corrosion, and thin protective films can be performed in greater detail than before. There are a few different types of nano infrared microscopes, but they all have in common that they are based on a combination of infrared (IR) spectroscopy and atomic force microscopy (AFM). In this article the theory of the different techniques is discussed, and some results are highlighted to show the ability of the technique in the field of corrosion science. Future possibilities of the technique in studies of corrosion and degradation of materials are also discussed. 

  • 438.
    Zhao, Yawei
    et al.
    Dalian Univ Technol, DUT KTH Joint Educ & Res Ctr Mol Devices, Inst Artificial Photosynth, Inst Energy Sci & Technol,State Key Lab Fine Chem, Dalian 116024, Peoples R China..
    Shen, Junyu
    Dalian Univ Technol, DUT KTH Joint Educ & Res Ctr Mol Devices, Inst Artificial Photosynth, Inst Energy Sci & Technol,State Key Lab Fine Chem, Dalian 116024, Peoples R China.;Changshu Inst Technol, Sch Chem & Mat Engn, Jiangsu Lab Adv Funct Mat, Changshu 215500, Jiangsu, Peoples R China..
    Yu, Ze
    Dalian Univ Technol, DUT KTH Joint Educ & Res Ctr Mol Devices, Inst Artificial Photosynth, Inst Energy Sci & Technol,State Key Lab Fine Chem, Dalian 116024, Peoples R China..
    Hu, Maowei
    Dalian Univ Technol, DUT KTH Joint Educ & Res Ctr Mol Devices, Inst Artificial Photosynth, Inst Energy Sci & Technol,State Key Lab Fine Chem, Dalian 116024, Peoples R China..
    Liu, Chong
    Jinan Univ, Coll Informat Sci & Technol, Inst New Energy Technol, Guangzhou 510632, Guangdong, Peoples R China..
    Fan, Jiandong
    Jinan Univ, Coll Informat Sci & Technol, Inst New Energy Technol, Guangzhou 510632, Guangdong, Peoples R China..
    Han, Hongxian
    Chinese Acad Sci, Dalian Inst Chem Phys, State Key Lab Catalysis, Dalian Natl Lab Clean Energy, Dalian 116023, Peoples R China..
    Hagfeldt, Anders
    Ecole Polytech Fed Lausanne, Lab Photomol Sci, CH-1015 Lausanne, Switzerland..
    Wang, Mei
    Dalian Univ Technol, DUT KTH Joint Educ & Res Ctr Mol Devices, Inst Artificial Photosynth, Inst Energy Sci & Technol,State Key Lab Fine Chem, Dalian 116024, Peoples R China..
    Sun, Licheng
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi. Dalian Univ Technol, DUT KTH Joint Educ & Res Ctr Mol Devices, Inst Artificial Photosynth, Inst Energy Sci & Technol,State Key Lab Fine Chem, Dalian 116024, Peoples R China.
    Fine-tuning the coordination atoms of copper redox mediators: an effective strategy for boosting the photovoltage of dye-sensitized solar cells2019Inngår i: Journal of Materials Chemistry A, ISSN 2050-7488, Vol. 7, nr 20, s. 12808-12814Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Natural systems have marvelously utilized copper complexes featuring sulfur-coordinating ligands, known as blue copper proteins, as efficient electron-transfer mediators in biological processes. Copper complexes with sulfur-coordinating ligands have been attempted as redox mediators in dye-sensitized solar cells (DSCs), the performance of which is not yet satisfactory and still remains less well explored. Herein, we report the application of new copper complexes bearing a tetradentate polythioether ligand, [(S-4)Cu](2+/+) (1(2+/+), S-4 = 1,4,8,11-tetrathiocyclotetradecane), as a redox mediator in DSCs in comparison with its N-4-tetradentate counterpart [(N-4)Cu](2+/+) (2(2+/+), N-4 = 1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecane). Impressively, the changes of coordination atoms from N to S positively shift the formal redox potential of the copper complexes by 600 mV, leading to a remarkably high photovoltage approaching 1.0 V. This is one of the highest photovoltage values reported thus far for DSCs based on copper redox mediators.

  • 439.
    Zhou, Nian
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap.
    Surface integrity and corrosion behavior of stainless steels after grinding operations2018Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Stainless steels are widely used in applications where both the mechanical properties of steels and high corrosion resistance are required. There is continuous research to enable stainless steel components to be produced in a more economical way and be used in more harsh environments. A way to achieve this is to correlate the service performance with the production processes.

    The central theme of this thesis is surface integrity and corrosion, especially the stress corrosion cracking behavior, after grinding processes. Controlled grinding parameters, including abrasive grit size, machine power and grinding lubricant, were used and the resulting surface properties studied for austenitic 304L and duplex 2304 stainless steels. The abrasive grit size effect was found to have a larger influence. Surface defects, a highly deformed surface layer and the generation of a high level surface tensile residual stresses along the grinding direction were observed as the main types of damage. 

    The effect of grinding on stress corrosion cracking behavior of austenitic 304L, ferritic 4509 and duplex 2304 stainless steels in chloride-containing environments was also investigated.  The abrasive grit size effect on corrosion behavior for the three grades was compared. Grinding-induced surface tensile residual stress was suggested as the main factor to cause micro-cracks on the ground surface for 304L and 2304; for 4509, grinding-induced grain fragmentation was considered as the main factor for the initiation of extensive micro-pits. For duplex 2304, the microstructure and micro-notches in the as-ground surface also had significant influence. Depending on the surface conditions, the actual loading by four-point bending was found to deviate from the calculated value using the formula according to ASTM G39 by different amounts. The knowledge obtained from this work can provide guidance for choosing appropriate stainless steel grades and grinding parameters; and can also be used to help understanding the failure mechanism of ground stainless steel components during service.

  • 440.
    Zhou, Nian
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap.
    Pettersson, Rachel
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap.
    Schönning, Mikael
    Lin Peng, Ru
    Influence of surface grinding on corrosion behavior of ferritic stainless steels in boiling magnesium chloride solution2018Inngår i: Materials and corrosion - Werkstoffe und Korrosion, ISSN 0947-5117, E-ISSN 1521-4176Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The influence of grinding operations on surface properties and corrosion behavior of a ferritic stainless steel (FSS), EN 1.4509, has been investigated and limited comparisons also made to the grade EN 1.4622. Surface grinding was performed along the rolling direction of the material. Corrosion tests were conducted in boiling magnesium chloride solution according to ASTM G36; specimens were exposed both without external loading and under four‐point bend loading. The surface topography and cross‐section microstructure before and after exposure were investigated, and residual stresses were measured on selected specimens before and after corrosion tests using X‐ray diffraction. In addition, in situ surface stress measurements were performed to evaluate the actual surface stresses of specimens subject to four‐point bend loading according to ASTM G39. Micro‐pits showing branched morphology initiated from the highly deformed ground surface layer which contained fragmented grains, were observed for all the ground specimens but not those in the as‐delivered condition. Grain boundaries under the surface layer appeared to hinder the corrosion process. No macro‐cracking was found on any specimen after exposure even at high calculated applied loads.

  • 441.
    Zhou, Yuye
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Tillämpad fysikalisk kemi.
    Romson, Joakim
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Tillämpad fysikalisk kemi.
    Emmer, Åsa
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Tillämpad fysikalisk kemi.
    An antibody-free sample pretreatment method for osteopontin combined with MALDI-TOF MS/MS analysis2019Inngår i: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 14, nr 3, artikkel-id e0213405Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Osteopontin is an osteoblast-secreted protein with an aspartic acid-rich, highly phosphorylated, and glycosylated structure. Osteopontin can easily bind to integrins, tumor cells, extracellular matrix and calcium, and is related to bone diseases, various cancers, inflammation etc. Here, DEAE-Cibacron blue 3GA was used to extract recombinant osteopontin from human plasma, and to deplete abundant plasma proteins with an antibody-free method. Using selected buffer systems, osteopontin and human serum albumin could be bound to DEAE-Cibacron blue 3GA, while immunoglobulin G was excluded. The bound osteopontin could then be separated from albumin by using different sequential elution buffers. By this method, 1 μg/mL recombinant osteopontin could be separated from the major part of the most abundant proteins in human plasma. After trypsin digestion, the extracted osteopontin could be successfully detected and identified by MALDI-TOF MS/MS using the m/z 1854.898 peptide and its fragments.

  • 442.
    Örnek, Cem
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap.
    Additive manufacturing–a general corrosion perspective2018Inngår i: Corrosion Engineering, Science and Technology, ISSN 1478-422X, E-ISSN 1743-2782, Vol. 53, nr 7, s. 531-535Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Metallic additive manufacturing will replace some materials produced by conventional fabrication methods in the nearest future. However, corrosion will remain an important aspect needed to be prevented. The corrosion behaviour of additively manufactured alloys has been sparsely studied and very little work has been published so far. In this article, a general discussion about materials produced by additive manufacturing will be provided. 

  • 443.
    Örnek, Cem
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap. KTH Royal Inst Technol, Sch Engn Sci Chem Biotechnol & Hlth, Div Surface & Corros Sci, Drottning Kristinas Vag 51, S-10044 Stockholm, Sweden..
    Stress Corrosion Cracking and Hydrogen Embrittlement of Type 316L Austenitic Stainless Steel Beneath MgCl2 and MgCl2: FeCl3 Droplets2019Inngår i: Corrosion, ISSN 0010-9312, E-ISSN 1938-159X, Vol. 75, nr 6, s. 657-667Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The atmospheric corrosion, as well as environmentally assisted cracking behavior of 316L austenitic stainless steel (UNS S31603) beneath MgCl2 and MgCl2: FeCl3 droplets under elastic and elastic-plastic strain exposed for 6 months at 50 degrees C and 30% relative humidity were investigated. Shallow and deep corrosion sites with filiform corrosion along with stress corrosion cracking (SCC) were formed beneath the salt-laden droplets, and the potential role of hydrogen embrittlement (HE) and crevice corrosion in damage evolution elucidated. Elastic strain (0.1%) was sufficient to cause SCC cracking as well as HE under droplets with 145 mu g/cmth> of chloride, with the severity of cracking increasing with increasing chloride deposition density (CDD). Elastic-plastic strain (0.2%) increased the propensity to both corrosion and SCC/HE, with cracks seen under droplets having CDD as low as 14.5 mu g/cm(2). Elastic-plastic strain was further seen to facilitate and accelerate pitting corrosion, leading to pits with more penetration depth. The extent of corrosion and cracking increases with increasing chloride deposition density, with ferric ions having more severe effect, in particular promoting localized corrosion with multiple nucleation sites. The work reported here was brought into a larger context of stainless steel corrosion and discussed in light of better understanding atmospheric corrosion of structural components such as nuclear waste storage containers.

  • 444.
    Örnek, Cem
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap.
    Engelberg, D. L.
    Univ Manchester, Corros & Protect Ctr, Sackville St, Manchester M13 9PL, Lancs, England.;Univ Manchester, Mat Performance Ctr, Sch Mat, Sackville St, Manchester M13 9PL, Lancs, England..
    Toward Understanding the Effects of Strain and Chloride Deposition Density on Atmospheric Chloride-Induced Stress Corrosion Cracking of Type 304 Austenitic Stainless Steel Under MgCl2 and FeCl3:MgCl2 Droplets2019Inngår i: Corrosion, ISSN 0010-9312, E-ISSN 1938-159X, Vol. 75, nr 2, s. 167-182Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Type 304 (UNS S30400) austenitic stainless steel was exposed for 6 months under elastic (0.1%) and elastic/plastic (0.2%) strain to MgCl2 and mixed MgCl2:FeCl3 droplets with varying chloride deposition densities (1.5 mu g/cm(2)-1,500 mu g/cm(2)) at 30% relative humidity (RH) and 50 degrees C. The occurrence of pitting corrosion, crevice corrosion, atmospheric chloride-induced stress corrosion cracking (AISCC), and hydrogen embrittlement (HE) was observed, and the average crack growth rates estimated. Exposure to elastic/plastic strain resulted in longer and more severe cracks. AISCC was found at chloride deposition densities down to 14.5 mu g/cm(2), whereas no cracks were seen at lower deposition densities, with cracks developing at pit or crevice corrosion sites. More severe cracks were seen under MgCl2 droplets as contrasted to mixed MgCl2:FeCl3 salt droplets, which were seen to promote more localized corrosion sites with deeper penetration and in conjunction with shorter crack lengths. Differences in AISCC propagation rates and associated crack morphologies are discussed in relation to understanding long-term atmospheric corrosion exposures.

  • 445.
    Örnek, Cem
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap.
    Leygraf, Christofer
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap.
    Pan, Jinshan
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap.
    On the Volta potential measured by SKPFM - fundamental and practical pects with relevance to corrosion science2019Inngår i: Corrosion Engineering, Science and Technology, ISSN 1478-422X, E-ISSN 1743-2782, Vol. 54, nr 3, s. 185-198Artikkel, forskningsoversikt (Fagfellevurdert)
    Abstract [en]

    The Volta potential is an electron-sensitive parameter and describes the ermodynamic propensity of a metal to take part in electrochemical actions. It has found widespread acceptance among corrosion searchers due to its connection to the corrosion potential and its sy measurability in local scale, being often used to study localised rrosion phenomena and micro-galvanic activities. The principle object this paper is to provide a comprehensive, fundamental insight into e meaning of the Volta potential and to define a polarity convention measured potentials by the scanning Kelvin probe force microscopy KPFM) in order to assess local nobilities in microstructures. nditions to relate the Volta potential with the mixed-potential theory e discussed and a possible connection to corrosion phenomena plained. The limitations of the Volta potential as well as the SKPFM chnique are also aimed to be explained, with some practical formation to maximise the output of high quality data.

  • 446.
    Örnek, Cem
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap.
    Leygraf, Christopher
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap.
    Pan, Jinshan
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap.
    Passive film characterisation of duplex stainless steel using scanning Kelvin probe force microscopy in combination with electrochemical measurements2019Inngår i: npJ Materials Degradation, ISSN 2397-2106, Vol. 3, nr 1, s. 1-8Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The characterisation of passive oxide films on heterogeneous microstructures is needed to assess local degradation (corrosion, cracking) in aggressive environments. The Volta potential is a surface-sensitive parameter which can be used to assess the surface nobility and hence passive films. In this work, it is shown that the Volta potential, measured on super duplex stainless steel by scanning Kelvin probe force microscopy, correlates with the electrochemical properties of the passive film, measured by electrochemical impedance spectroscopy and potentiodynamic polarisation. Natural oxidation by ageing in ambient air as well as artificial oxidation by immersion in concentrated nitric acid improved the nobility, both reflected by increased Volta potentials and electrochemical parameters. Passivation was associated with vanishing of the inherent Volta potential difference between the ferrite and austenite, thereby reducing the galvanic coupling and hence improving the corrosion resistance of the material. Hydrogen-passive film interactions, triggered by cathodic polarisation, however, largely increased the Volta potential difference between the phases, resulting in loss of electrochemical nobility, with the ferrite being more affected than the austenite. A correlative approach of using the Volta potential in conjunction with electrochemical data has been introduced to characterise the nobility of passive films in global and local scale.

  • 447.
    Örnek, Cem
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap. Swerea KIMAB AB, Isafjordsgatan 28A, Kista, 164 40, Sweden.
    Liu, Min
    Univ Sci & Technol Beijing, Natl Ctr Mat Serv Safety, Xueyuan Rd 30, Beijing 100083, Peoples R China..
    Pan, Ying
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap.
    Jin, Y.
    Univ Sci & Technol Beijing, Natl Ctr Mat Serv Safety, Xueyuan Rd 30, Beijing 100083, Peoples R China..
    Leygraf, Christopher
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap.
    Volta Potential Evolution of Intermetallics in Aluminum Alloy Microstructure Under Thin Aqueous Adlayers: A combined DFT and Experimental Study2018Inngår i: Topics in catalysis, ISSN 1022-5528, E-ISSN 1572-9028, Vol. 61, nr 9-11, s. 1169-1182Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this work, first-principle density functional theory (DFT) was used to calculate the work function and Volta potential differences between aluminum alloy matrix and two intermetallic phases (Mg2Si and Al2Cu) with varying surface terminations as a function of adhering monolayers (ML) of water. The calculated data were compared with experimental local Volta potential data obtained by the scanning Kelvin probe force microscopy (SKPFM) on a commercial aluminum alloy AA6063-T5 in atmospheric environments with varying relative humidity (RH). The calculations suggest that the surface termination has a major effect on the magnitude and polarity of the Volta potential of both intermetallic phases (IMP's). The Volta potential difference between the IMP's and the aluminum matrix decreases when the surface is gradually covered by water molecules, and may further change as a function of adhering ML's of water. This can lead to nobility inversions of the IMP's relative to the aluminum matrix. The measured Volta potential difference between both IMP's and their neighboring matrix is dependent on RH. Natural oxidation in ambient indoor air for 2 months led to a nobility inversion of the IMP's with respect to the aluminum matrix, with the intermetallics showing anodic nature already in dry condition. The anodic nature of Al2Cu remained with the introduction of RH, whereas Mg2Si became cathodic at high RH, presumably due to de-alloying of Mg and oxide dissolution. The DFT calculations predicted an anodic character of both IMP's in reference to the oxidized aluminum matrix, being in good agreement with the SKPFM data. The DFT and SKPFM data were discussed in light of understanding localized corrosion of aluminum alloys under conditions akin to atmospheric exposure.

  • 448.
    Örnek, Cem
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap.
    Långberg, Marie
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap.
    Evertsson, Jonas
    Lund Univ, Div Synchrotron Radiat Res, SE-22100 Lund, Sweden..
    Harlow, Gary
    Lund Univ, Div Synchrotron Radiat Res, SE-22100 Lund, Sweden..
    Linpe, Weronica
    Lund Univ, Div Synchrotron Radiat Res, SE-22100 Lund, Sweden..
    Rullik, Lisa
    Lund Univ, Div Synchrotron Radiat Res, SE-22100 Lund, Sweden..
    Carla, Francesco
    European Synchrotron Radiat Facil, F-38000 Grenoble, France..
    Felici, Roberto
    Area Ric Roma 2 Tor Vergata, SPINCNR, I-00133 Rome, Italy..
    Bettini, Eleonora
    Sandvik Mat Technol, SE-81181 Sandviken, Sweden..
    Kivisakk, Ulf
    Sandvik Mat Technol, SE-81181 Sandviken, Sweden..
    Lundgren, Edvin
    Lund Univ, Div Synchrotron Radiat Res, SE-22100 Lund, Sweden..
    Pan, Jinshan
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    In-situ synchrotron GIXRD study of passive film evolution on duplex stainless steel in corrosive environment2018Inngår i: Corrosion Science, ISSN 0010-938X, E-ISSN 1879-0496, Vol. 141, s. 18-21Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper presents new findings about the passive film formed on super duplex stainless steel in ambient air and corrosive environments, studied by synchrotron grazing-incidence X-ray diffraction (GIXRD). The passive film, formed in air, was seen to be a nano-crystalline mixed-oxide. Electrochemical polarisation to the passive region in aqueous 1 M NaCl at room temperature resulted in an increase of the passive film thickness, preferential dissolution of Fe, and partial loss of crystallinity. After termination of polarization to the transpassive regime, reformation of the mixed-oxides was observed, showing a thicker, semi-crystalline, and more defective nature (more vacancies) with further new oxides/hydroxides.

  • 449.
    Örnek, Cem
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap.
    Långberg, Marie
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap. Swerim, SE-16407 Kista, Sweden..
    Evertsson, Jonas
    Lund Univ, Div Synchrotron Radiat Res, SE-22100 Lund, Sweden.;Deutsch Elektronen Synchrotron DESY, D-22607 Hamburg, Germany.;Justus Liebig Univ Giessen, Phys Chem Dept, D-35392 Giessen, Germany..
    Harlow, Gary
    Lund Univ, Div Synchrotron Radiat Res, SE-22100 Lund, Sweden..
    Linpe, Weronica
    Lund Univ, Div Synchrotron Radiat Res, SE-22100 Lund, Sweden..
    Rullik, Lisa
    Lund Univ, Div Synchrotron Radiat Res, SE-22100 Lund, Sweden..
    Carla, Francesco
    Diamond Light Source, Didcot OX11 0DE, Oxon, England..
    Felici, Roberto
    SPINCNR, Area Ric Roma 2 Tor Vergata, I-00133 Rome, Italy..
    Kivisakk, Ulf
    Sandvik Mat Technol, SE-81181 Sandviken, Sweden..
    Lundgren, Edvin
    Lund Univ, Div Synchrotron Radiat Res, SE-22100 Lund, Sweden..
    Pan, Jinshan
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap.
    Influence of Surface Strain on Passive Film Formation of Duplex Stainless Steel and Its Degradation in Corrosive Environment2019Inngår i: Journal of the Electrochemical Society, ISSN 0013-4651, E-ISSN 1945-7111, Vol. 166, nr 11, s. C3071-C3080Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The effect of surface strain on the passive film evolution of SAF 2507 super duplex stainless steel exposed to ambient air and 0.1 M NaCl solution with varying anodic polarization at room temperature has been investigated using in-situ grazing incidence X-ray diffraction (GIXRD) in combination with electrochemical measurements. Surface strain affected the crystallinity of the passive film as such that the surface oxides/hydroxides were predominantly amorphous, with some minor crystalline CrOOH and FeOOH present in the film. Crystalline CrOOH was seen to diminish in volume upon immersion in the NaCl solution, well-possibly becoming amorphous during anodic polarization, whereas crystalline FeOOH was seen to increase in volume during polarization to the passive potential regime. Strain relaxation, associated with metal dissolution, occurred in both austenitic and ferritic grains during immersion in the electrolyte. Anodic polarization to the transpassive regime led to maximum strain relaxation, occurring more on the austenite than the ferrite. The selective transpassive dissolution nature of the ferrite was significantly reduced due to large strains in the austenite. Passive film breakdown was reflected by enhanced dissolution of Fe, Cr, Mo and Ni occurring simultaneously around 1300 mV vs. Ag/AgCl. 

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