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Li, Z., Li, Y., Cheng, H., Song, Y., Jiao, Y., Shi, S., . . . Hou, J. (2024). Atomically dispersed Ni active sites on covalent organic frameworks for heterogeneous metallaphotocatalytic C–N cross-coupling. Applied Catalysis B: Environmental, 345, Article ID 123698.
Open this publication in new window or tab >>Atomically dispersed Ni active sites on covalent organic frameworks for heterogeneous metallaphotocatalytic C–N cross-coupling
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2024 (English)In: Applied Catalysis B: Environmental, ISSN 0926-3373, E-ISSN 1873-3883, Vol. 345, article id 123698Article in journal (Refereed) Published
Abstract [en]

Covalent organic frameworks (COFs) have been acknowledged as a potential platform for heterogeneous photoredox cross-coupling due to their excellent chemical stability, admirable controllability, and extremely prominent surface area. However, synthesizing COFs with bidentate ligand units and utilizing active sites remain a grand challenge. Herein, we report a promising new family of 2,6-pyridinedicarboxaldehyde-bis-(p-aminophenylimine)-based two-dimensional (2D) COFs (PP-COF) using an amine monomer and classic tri-aldehydes. On this basis, dispersed Ni single-atom sites were immobilized on three-types imine-based bi-coordinated 2D COFs (Ni SAS-PP-COF) as heterogeneous dual photoredox catalysts for photo/Ni dual-catalyzed C–N cross-coupling between aryl bromides and alkyl/sulfo amines. Under solar energy irradiation, PP-COF could absorb light to generate electrons and holes, then the photogenerated electrons are transferred to Ni sites to reduce divalent nickel to monovalent nickel. Monovalent nickel is necessary to drive the nickel catalytic cycle. Due to the increased charge separation and abundant active sites, the state-of-the-art Ni SAS-PP-COFs catalyst achieves excellent catalytic performance in comparison of pristine PP-COF. The heterogeneous Ni SAS-PP-COF catalytic system not only confirms the prospect of COFs as potential photoredox/transition-metal dual catalysts, but also provides in-depth insights into the synthesis of functional COFs toward practical metallaphotocatalytic application.

Place, publisher, year, edition, pages
Elsevier BV, 2024
Keywords
Covalent organic frameworks, C–N cross-coupling, Dispersed Ni single-atom sites, Heterogeneous photocatalyst, Metallaphotocatalysis
National Category
Organic Chemistry
Identifiers
urn:nbn:se:kth:diva-342377 (URN)10.1016/j.apcatb.2024.123698 (DOI)2-s2.0-85181969143 (Scopus ID)
Note

QC 20240122

Available from: 2024-01-17 Created: 2024-01-17 Last updated: 2024-01-22Bibliographically approved
Liu, C., Li, F., Wang, L., Li, Z., Zhao, Y., Li, Y., . . . Sun, L. (2024). Polymeric viologen-based electron transfer mediator for improving the photoelectrochemical water splitting on Sb2Se3 photocathode. Fundamental Research, 4(2), 291-299
Open this publication in new window or tab >>Polymeric viologen-based electron transfer mediator for improving the photoelectrochemical water splitting on Sb2Se3 photocathode
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2024 (English)In: Fundamental Research, ISSN 2667-3258, Vol. 4, no 2, p. 291-299Article in journal (Refereed) Published
Abstract [en]

The photogenerated charge carrier separation and transportation of inside photocathodes can greatly influence the performance of photoelectrochemical (PEC) H2 production devices. Coupling TiO2 with p-type semiconductors to construct heterojunction structures is one of the most widely used strategies to facilitate charge separation and transportation. However, the band position of TiO2 could not perfectly match with all p-type semiconductors. Here, taking antimony selenide (Sb2Se3) as an example, a rational strategy was developed by introducing a viologen electron transfer mediator (ETM) containing polymeric film (poly-1,1′-dially-[4,4′-bipyridine]-1,1′-diium, denoted as PV2+) at the interface between Sb2Se3 and TiO2 to regulate the energy band alignment, which could inhibit the recombination of photogenerated charge carriers of interfaces. With Pt as a catalyst, the constructed Sb2Se3/PV2+/TiO2/Pt photocathode showed a superior PEC hydrogen generation activity with a photocurrent density of −18.6 mA cm−2 vs. a reversible hydrogen electrode (RHE) and a half-cell solar-to-hydrogen efficiency (HC-STH) of 1.54% at 0.17 V vs. RHE, which was much better than that of the related Sb2Se3/TiO2/Pt photocathode without PV2+ (−9.8 mA cm−2, 0.51% at 0.10 V vs. RHE). 

Place, publisher, year, edition, pages
Elsevier BV, 2024
Keywords
Electron transfer mediator, Hydrogen evolution reaction, Sb2Se3 photocathode, Solar water splitting, Viologen
National Category
Physical Chemistry
Identifiers
urn:nbn:se:kth:diva-322990 (URN)10.1016/j.fmre.2022.03.013 (DOI)001223117400001 ()2-s2.0-85127959372 (Scopus ID)
Note

QC 20230111

Available from: 2023-01-11 Created: 2023-01-11 Last updated: 2024-05-27Bibliographically approved
Chang, Q., An, Y., Cao, H., Pan, Y., Zhao, L., Chen, Y., . . . Yu, Z. (2024). Precursor engineering enables high-performance all-inorganic CsPbIBr2 perovskite solar cells with a record efficiency approaching 13%. Journal of Energy Chemistry, 90, 16-22
Open this publication in new window or tab >>Precursor engineering enables high-performance all-inorganic CsPbIBr2 perovskite solar cells with a record efficiency approaching 13%
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2024 (English)In: Journal of Energy Chemistry, ISSN 2095-4956, E-ISSN 2096-885X, Vol. 90, p. 16-22Article in journal (Refereed) Published
Abstract [en]

All-inorganic CsPbIBr2 perovskite has attracted widespread attention in photovoltaic and other optoelectronic devices because of its superior thermal stability. However, the deposition of high-quality solution-processed CsPbIBr2 perovskite films with large thicknesses remains challenging. Here, we develop a triple-component precursor (TCP) by employing lead bromide, lead iodide, and cesium bromide, to replace the most commonly used double-component precursor (DCP) consisting of lead bromide and cesium iodide. Remarkably, the TCP system significantly increases the solution concentration to 1.3 M, leading to a larger film thickness (∼390 nm) and enhanced light absorption. The resultant CsPbIBr2 films were evaluated in planar n-i-p structured solar cells, which exhibit a considerably higher optimal photocurrent density of 11.50 mA cm−2 in comparison to that of DCP-based devices (10.69 mA cm−2). By adopting an organic surface passivator, the maximum device efficiency using TCP is further boosted to a record efficiency of 12.8% for CsPbIBr2 perovskite solar cells.

Place, publisher, year, edition, pages
Elsevier BV, 2024
Keywords
All-inorganic perovskite solar cells, CsPbIBr 2, High performance, Precursor engineering, Solubility
National Category
Materials Chemistry
Identifiers
urn:nbn:se:kth:diva-341611 (URN)10.1016/j.jechem.2023.10.021 (DOI)001127576100001 ()2-s2.0-85179041429 (Scopus ID)
Note

QC 20231227

Available from: 2023-12-27 Created: 2023-12-27 Last updated: 2024-01-10Bibliographically approved
Liu, T., Zhan, S., Shen, N., Wang, L., Szabo, Z., Yang, H., . . . Sun, L. (2023). Bioinspired Active Site with a Coordination-Adaptive Organosulfonate Ligand for Catalytic Water Oxidation at Neutral pH. Journal of the American Chemical Society, 145(21), 11818-11828
Open this publication in new window or tab >>Bioinspired Active Site with a Coordination-Adaptive Organosulfonate Ligand for Catalytic Water Oxidation at Neutral pH
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2023 (English)In: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 145, no 21, p. 11818-11828Article in journal (Refereed) Published
Abstract [en]

Many enzymes use adaptive frameworks to preorganize substrates, accommodate various structural and electronic demands of intermediates, and accelerate related catalysis. Inspired by biological systems, a Ru-based molecular water oxidation catalyst containing a configurationally labile ligand [2,2′:6′,2″-terpyridine]-6,6″-disulfonate was designed to mimic enzymatic framework, in which the sulfonate coordination is highly flexible and functions as both an electron donor to stabilize high-valent Ru and a proton acceptor to accelerate water dissociation, thus boosting the catalytic water oxidation performance thermodynamically and kinetically. The combination of single-crystal X-ray analysis, various temperature NMR, electrochemical techniques, and DFT calculations was utilized to investigate the fundamental role of the self-adaptive ligand, demonstrating that the on-demand configurational changes give rise to fast catalytic kinetics with a turnover frequency (TOF) over 2000 s–1, which is compared to oxygen-evolving complex (OEC) in natural photosynthesis. 

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2023
National Category
Chemical Sciences
Identifiers
urn:nbn:se:kth:diva-327110 (URN)10.1021/jacs.3c03415 (DOI)001011072400001 ()37196315 (PubMedID)2-s2.0-85160751257 (Scopus ID)
Funder
Swedish Research Council, 2017-00935
Note

QC 20230523

Available from: 2023-05-19 Created: 2023-05-19 Last updated: 2024-03-15Bibliographically approved
Zhao, Y., Ran, L., Chen, R., Song, Y., Gao, J., Sun, L. & Hou, J. (2023). Boosting Charge Mediation in Ferroelectric BaTiO3−x-Based Photoanode for Efficient and Stable Photoelectrochemical Water Oxidation. Small Structures, 4(9), Article ID 2300072.
Open this publication in new window or tab >>Boosting Charge Mediation in Ferroelectric BaTiO3−x-Based Photoanode for Efficient and Stable Photoelectrochemical Water Oxidation
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2023 (English)In: Small Structures, E-ISSN 2688-4062, Vol. 4, no 9, article id 2300072Article in journal (Refereed) Published
Abstract [en]

Oxygen evolution reaction (OER) is a bottleneck to photoelectrochemical (PEC) water splitting; however, there remains an impressive challenge for intrinsic charge transport for the development of integrated photoanodes. Herein, covalent triazine frameworks as conjugated molecules are grafted on the surfaces of ferroelectric BaTiO3−x (CTF/BTO) nanorod array, and then oxyhydroxide oxygen evolution cocatalyst (OEC) is constructed as an integrated photoanode. The OEC/CTF/BTO array not only achieves a high photocurrent density of 0.83 mA cm−2 at 1.23 V versus reversible hydrogen electrode (vs RHE) and low onset potential of ≈0.23 VRHE, but also optimizes outstanding stability. To disclose the origin, the enhanced PEC activity can be contributed to the integration of CTF and OEC, enhancing light-harvesting capability, boosting charge carrier mediation, and promoting water oxidation kinetics through electrochemical analysis and density functional theory calculations. This study not only provides an alternative to accelerate charge transfer, but also paves the rational design and fabrication of integrated photoanodes for boosting PEC water splitting performance.

Place, publisher, year, edition, pages
Wiley, 2023
Keywords
charge mediation, covalent triazine frameworks, ferroelectric BaTiO photoanodes 3−x, heterostructure photoanodes, photoelectrochemical water oxidation
National Category
Materials Chemistry
Identifiers
urn:nbn:se:kth:diva-349834 (URN)10.1002/sstr.202300072 (DOI)000951755500001 ()2-s2.0-85167407803 (Scopus ID)
Note

QC 20240703

Available from: 2024-07-03 Created: 2024-07-03 Last updated: 2024-07-03Bibliographically approved
Svanström, S., Garcia Fernandez, A., Sloboda, T., Jacobsson, T. J., Zhang, F., Johansson, F. O. L., . . . Cappel, U. B. (2023). Direct Measurements of Interfacial Photovoltage and Band Alignment in Perovskite Solar Cells Using Hard X-ray Photoelectron Spectroscopy. ACS Applied Materials and Interfaces, 15(9), 12485-12494
Open this publication in new window or tab >>Direct Measurements of Interfacial Photovoltage and Band Alignment in Perovskite Solar Cells Using Hard X-ray Photoelectron Spectroscopy
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2023 (English)In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 15, no 9, p. 12485-12494Article in journal (Refereed) Published
Abstract [en]

A heterojunction is the key junction for charge extraction in many thin film solar cell technologies. However, the structure and band alignment of the heterojunction in the operating device are often difficult to predict from calculations and, due to the complexity and narrow thickness of the interface, are difficult to measure directly. In this study, we demonstrate a technique for direct measurement of the band alignment and interfacial electric field variations of a fully functional lead halide perovskite solar cell structure under operating conditions using hard X-ray photoelectron spectroscopy (HAXPES). We describe the design considerations required in both the solar cell devices and the measurement setup and show results for the perovskite, hole transport, and gold layers at the back contact of the solar cell. For the investigated design, the HAXPES measurements suggest that 70% of the photovoltage was generated at this back contact, distributed rather equally between the hole transport material/gold interface and the perovskite/hole transport material interface. In addition, we were also able to reconstruct the band alignment at the back contact at equilibrium in the dark and at open circuit under illumination.

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2023
Keywords
operando measurements, photoelectron spectroscopy, photovoltaics, semiconductor physics, experimental design, device design, lead halide perovskite, solar cell
National Category
Physical Chemistry
Identifiers
urn:nbn:se:kth:diva-325605 (URN)10.1021/acsami.2c17527 (DOI)000949872700001 ()36847773 (PubMedID)2-s2.0-85149113773 (Scopus ID)
Note

QC 20230412

Available from: 2023-04-12 Created: 2023-04-12 Last updated: 2023-12-04Bibliographically approved
Zhao, Y., Ding, Y., Li, W., Liu, C., Li, Y., Zhao, Z., . . . Li, F. (2023). Efficient urea electrosynthesis from carbon dioxide and nitrate via alternating Cu–W bimetallic C–N coupling sites. Nature Communications, 14(1), Article ID 4491.
Open this publication in new window or tab >>Efficient urea electrosynthesis from carbon dioxide and nitrate via alternating Cu–W bimetallic C–N coupling sites
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2023 (English)In: Nature Communications, E-ISSN 2041-1723, Vol. 14, no 1, article id 4491Article in journal (Refereed) Published
Abstract [en]

Electrocatalytic urea synthesis is an emerging alternative technology to the traditional energy-intensive industrial urea synthesis protocol. Novel strategies are urgently needed to promote the electrocatalytic C–N coupling process and inhibit the side reactions. Here, we report a CuWO4 catalyst with native bimetallic sites that achieves a high urea production rate (98.5 ± 3.2 μg h−1 mg−1cat) for the co-reduction of CO2 and NO3− with a high Faradaic efficiency (70.1 ± 2.4%) at −0.2 V versus the reversible hydrogen electrode. Mechanistic studies demonstrated that the combination of stable intermediates of *NO2 and *CO increases the probability of C–N coupling and reduces the potential barrier, resulting in high Faradaic efficiency and low overpotential. This study provides a new perspective on achieving efficient urea electrosynthesis by stabilizing the key reaction intermediates, which may guide the design of other electrochemical systems for high-value C–N bond-containing chemicals.

Place, publisher, year, edition, pages
Springer Nature, 2023
National Category
Physical Chemistry
Identifiers
urn:nbn:se:kth:diva-335714 (URN)10.1038/s41467-023-40273-2 (DOI)001038216100018 ()37495582 (PubMedID)2-s2.0-85165918229 (Scopus ID)
Note

QC 20230912

Available from: 2023-09-12 Created: 2023-09-12 Last updated: 2024-03-15Bibliographically approved
Zhang, B., Chang, Y., Zhai, P., Wang, C., Gao, J., Sun, L. & Hou, J. (2023). Enriching Metal–Oxygen Species and Phosphate Modulating of Active Sites for Robust Electrocatalytical CO2 Reduction. Advanced Materials, 35(46), Article ID 2304379.
Open this publication in new window or tab >>Enriching Metal–Oxygen Species and Phosphate Modulating of Active Sites for Robust Electrocatalytical CO2 Reduction
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2023 (English)In: Advanced Materials, ISSN 0935-9648, E-ISSN 1521-4095, Vol. 35, no 46, article id 2304379Article in journal (Refereed) Published
Abstract [en]

Direct electrochemical reduction of CO2 (CO2RR) into value-added chemicals is a promising solution to reduce carbon emissions. The activity of CO2RR is influenced deeply by the reaction microenvironment and electronic properties of the catalysts. Herein, the surface PO43− anions are tuned to modulate the local microenvironment and the electronic properties of the indium-based catalyst with abundant metal–oxygen species enabling efficient electrochemical conversion of CO2 to HCOO−. Indium nanoparticles coupled with PO43− anions (PO43−-In NPs) achieve a high selectivity of HCOO− up to 91.4% at a low potential of −0.98 V versus reversible hydrogen electrode (versus RHE) and a high HCOO− partial current density of 279.3 mA cm−2 at −1.1 V versus RHE in the electrochemical flow cell. In situ and ex situ characterizations confirm the PO43− anions keep stable on the surface of indium during CO2RR, accelerating the generation of OCHO* intermediate. From density functional theory calculations, PO43− anions enrich the metal–oxygen species on the substrate to optimize the electronic structure of the catalysts and induce a local microenvironment with massive K+ ions on the interface, thus reducing the activation energy barrier of CO2RR.

Place, publisher, year, edition, pages
Wiley, 2023
Keywords
CO electrocatalysis 2, in situ characterization methods, local microenvironment, metal–oxygen species, phosphate
National Category
Materials Chemistry
Identifiers
urn:nbn:se:kth:diva-347504 (URN)10.1002/adma.202304379 (DOI)001082888200001 ()37487190 (PubMedID)2-s2.0-85173901983 (Scopus ID)
Note

QC 20240619

Available from: 2024-06-19 Created: 2024-06-19 Last updated: 2024-06-19Bibliographically approved
Fan, L., Song, Y., Zhang, F., Timmer, B., Kravberg, A., Zhang, B. & Sun, L. (2023). Holistic functional biomimetics: a key to make an efficient electrocatalyst for water oxidation. Journal of Materials Chemistry A, 11(20), 10669-10676
Open this publication in new window or tab >>Holistic functional biomimetics: a key to make an efficient electrocatalyst for water oxidation
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2023 (English)In: Journal of Materials Chemistry A, ISSN 2050-7488, E-ISSN 2050-7496, Vol. 11, no 20, p. 10669-10676Article in journal (Refereed) Published
Abstract [en]

Water oxidation is the holy grail reaction of natural and artificial photosynthesis. How to design an efficient water-oxidation catalyst remains a long-term challenge for solar fuel production. The rate of water oxidation in photosystem II by the oxygen-evolving complex (OEC) Mn4CaO5 cluster is as high as 100-400 s−1. Mimicking the structures of the OEC is a straightforward strategy to design water-oxidation catalysts. However, the high efficiency of the OEC relies on not only its highly active site but also its holistic system for well-organized electron transfer and proton transport. Lacking such a holistic functional system makes δ-MnO2 a poor water-oxidation catalyst, although the local structure of δ-MnO2 is similar to that of the Mn4CaO5 cluster. Electrocatalysts simultaneously imitating the catalytically active sites, fast electron transfer, and promoted proton transport in a natural OEC have been rarely reported. The significance of the synergy of a holistic system is underrated in the design of water-oxidation catalysts. In this work, we fabricated holistic functional biomimetic composites of two-dimensional manganese oxide nanosheets and pyridyl-modified graphene (MnOx-NS/py-G) for electrocatalytic water oxidation. MnOx-NS/py-G simultaneously imitates the synergy of catalytically active sites, fast electron transfer, and promoted proton transport in a natural OEC, resulting in overall 600 times higher activity than that of typical δ-MnO2. This work demonstrates the significance of holistic functional biomimetic design and guides the development of highly active electrocatalysts for small molecule activation related to solar energy storage.

Place, publisher, year, edition, pages
Royal Society of Chemistry (RSC), 2023
National Category
Physical Chemistry Materials Chemistry
Identifiers
urn:nbn:se:kth:diva-331571 (URN)10.1039/d3ta01040f (DOI)000983915400001 ()2-s2.0-85159156124 (Scopus ID)
Note

QC 20230711

Available from: 2023-07-11 Created: 2023-07-11 Last updated: 2023-09-06Bibliographically approved
Wang, C., Zhai, P., Xia, M., Liu, W., Gao, J., Sun, L. & Hou, J. (2023). Identification of the Origin for Reconstructed Active Sites on Oxyhydroxide for Oxygen Evolution Reaction. Advanced Materials, 35(6), Article ID 2209307.
Open this publication in new window or tab >>Identification of the Origin for Reconstructed Active Sites on Oxyhydroxide for Oxygen Evolution Reaction
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2023 (English)In: Advanced Materials, ISSN 0935-9648, E-ISSN 1521-4095, Vol. 35, no 6, article id 2209307Article in journal (Refereed) Published
Abstract [en]

The regulation of atomic and electronic structures of active sites plays an important role in the rational design of oxygen evolution reaction (OER) catalysts toward electrocatalytic hydrogen generation. However, the precise identification of the active sites for surface reconstruction behavior during OER remains elusive for water-alkali electrolysis. Herein, irreversible reconstruction behavior accompanied by copper dynamic evolution for cobalt iron layered double hydroxide (CoFe LDH) precatalyst to form CoFeCuOOH active species with high-valent Co species is reported, identifying the origin of reconstructed active sites through operando UV-Visible (UV–vis), in situ Raman, and X-ray absorption fine-structure (XAFS) spectroscopies. Density functional theory analysis rationalizes this typical electronic structure evolution causing the transfer of intramolecular electrons to form ligand holes, promoting the reconstruction of active sites. Specifically, unambiguous identification of active sites for CoFeCuOOH is explored by in situ 18O isotope-labeling differential electrochemical mass spectrometry (DEMS) and supported by theoretical calculation, confirming mechanism switch to oxygen-vacancy-site mechanism (OVSM) pathway on lattice oxygen. This work enables to elucidate the vital role of dynamic active-site generation and the representative contribution of OVSM pathway for efficient OER performance.

Place, publisher, year, edition, pages
Wiley, 2023
Keywords
irreversible reconstruction behavior, oxygen evolution reaction, oxygen-vacancy-site mechanism, reconstruction of active sites, transfer of intramolecular electron
National Category
Organic Chemistry
Identifiers
urn:nbn:se:kth:diva-328710 (URN)10.1002/adma.202209307 (DOI)000898794300001 ()36408935 (PubMedID)2-s2.0-85144299946 (Scopus ID)
Note

QC 20230613

Available from: 2023-06-13 Created: 2023-06-13 Last updated: 2023-06-13Bibliographically approved
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ORCID iD: ORCID iD iconorcid.org/0000-0002-4521-2870

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