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Chen, Hong
Publications (10 of 10) Show all publications
Zhang, P., Li, L., Nordlund, D., Chen, H., Fan, L., Zhang, B., . . . Sun, L. (2018). Dendritic core-shell nickel-iron-copper metal/metal oxide electrode for efficient electrocatalytic water oxidation. Nature Communications, 9(1), Article ID 381.
Open this publication in new window or tab >>Dendritic core-shell nickel-iron-copper metal/metal oxide electrode for efficient electrocatalytic water oxidation
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2018 (English)In: Nature Communications, ISSN 2041-1723, E-ISSN 2041-1723, Vol. 9, no 1, article id 381Article in journal (Refereed) Published
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.

Place, publisher, year, edition, pages
Nature Publishing Group, 2018
National Category
Other Chemistry Topics
Identifiers
urn:nbn:se:kth:diva-222290 (URN)10.1038/s41467-017-02429-9 (DOI)2-s2.0-85041107994 (Scopus ID)
Note

QC 20180206

Available from: 2018-02-06 Created: 2018-02-06 Last updated: 2018-02-06Bibliographically approved
Wang, L., Zhang, J., Liu, P., Xu, B., Zhang, B., Chen, H., . . . Sun, L. (2018). Design and synthesis of dopant-free organic hole-transport materials for perovskite solar cells. Chemical Communications, 54(69)
Open this publication in new window or tab >>Design and synthesis of dopant-free organic hole-transport materials for perovskite solar cells
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2018 (English)In: Chemical Communications, ISSN 1359-7345, E-ISSN 1364-548X, Vol. 54, no 69Article in journal (Refereed) Published
Abstract [en]

Two novel dopant-free hole-transport materials (HTMs) with spiro[dibenzo[c,h]xanthene-7,9-fluorene] (SDBXF) skeletons were prepared via facile synthesis routes. A power conversion efficiency of 15.9% in perovskite solar cells is attained by using one HTM without dopants, which is much higher than undoped Spiro-OMeTAD-based devices (10.8%). The crystal structures of both new HTMs were systematically investigated to reveal the reasons behind such differences in performance and to indicate the design principles of more advanced HTMs.

Place, publisher, year, edition, pages
ROYAL SOC CHEMISTRY, 2018
National Category
Textile, Rubber and Polymeric Materials
Identifiers
urn:nbn:se:kth:diva-234569 (URN)10.1039/c8cc04026e (DOI)000442605100002 ()30043013 (PubMedID)2-s2.0-85052539543 (Scopus ID)
Funder
Swedish Energy Agency
Note

QC 20180917

Available from: 2018-09-17 Created: 2018-09-17 Last updated: 2018-10-19Bibliographically approved
Daniel, Q., Duan, L., Timmer, B. J. J., Chen, H., Luo, X., Ambre, R., . . . Sun, L. (2018). Water Oxidation Initiated by In Situ Dimerization of the Molecular Ru(pdc) Catalyst. ACS Catalysis, 8(5), 4375-4382
Open this publication in new window or tab >>Water Oxidation Initiated by In Situ Dimerization of the Molecular Ru(pdc) Catalyst
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2018 (English)In: ACS Catalysis, ISSN 2155-5435, E-ISSN 2155-5435, Vol. 8, no 5, p. 4375-4382Article in journal (Refereed) Published
Abstract [en]

The mononuclear ruthenium complex [Ru(pdc)L-3] (H(2)pdc = 2,6-pyridinedicarboxylic acid, L = N-heterocycles such as 4-picoline) has previously shown promising catalytic efficiency toward water oxidation, both in homogeneous solutions and anchored on electrode surfaces. However, the detailed water oxidation mechanism catalyzed by this type of complex has remained unclear. In order to deepen understanding of this type of catalyst, in the present study, [Ru(pdc)(py)(3)] (py = pyridine) has been synthesized, and the detailed catalytic mechanism has been studied by electrochemistry, UV-vis, NMR, MS, and X-ray crystallography. Interestingly, it was found that once having reached the Ru-IV state, this complex promptly formed a stable ruthenium dimer [Ru-III(pdc)(py)(2)-O-Ru-IV(pdc)(py)(2)](+). Further investigations suggested that the present dimer, after one pyridine ligand exchange with water to form [Ru-III(pdc)(py)(2)-O-Ru-IV(pdc)(py)(H2O)](+), was the true active species to catalyze water oxidation in homogeneous solutions.

Place, publisher, year, edition, pages
AMER CHEMICAL SOC, 2018
Keywords
solar fuels, water oxidation, electrochemistry, ruthenium dimer, mechanism of O-O bond formation
National Category
Organic Chemistry
Identifiers
urn:nbn:se:kth:diva-231630 (URN)10.1021/acscatal.7b03768 (DOI)000431727300070 ()2-s2.0-85046695744 (Scopus ID)
Note

QC 20180702

Available from: 2018-07-02 Created: 2018-07-02 Last updated: 2018-07-02Bibliographically approved
Zhang, P., Chen, H., Wang, M., Yang, Y., Jiang, J., Zhang, B., . . . Sun, L. (2017). Gas-templating of hierarchically structured Ni-Co-P for efficient electrocatalytic hydrogen evolution. Journal of Materials Chemistry A, 5(16), 7564-7570
Open this publication in new window or tab >>Gas-templating of hierarchically structured Ni-Co-P for efficient electrocatalytic hydrogen evolution
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2017 (English)In: Journal of Materials Chemistry A, ISSN 2050-7488, Vol. 5, no 16, p. 7564-7570Article in journal (Refereed) Published
Abstract [en]

One of the grand challenges for developing scalable and sustainable hydrogen producing systems is the lack of efficient and robust earth-abundant element based catalysts for the hydrogen evolution reaction (HER). Herein, a hierarchically structured Ni-Co-P film was fabricated via a gas templating electro-deposition method. This film exhibits remarkably high catalytic performance for the HER in 1 M KOH with respective current densities of -10 and -500 mA cm(-2) at the overpotentials of -30 and -185 mV with a Tafel slope of 41 mV dec(-1). A controlled potential electrolysis experiment demonstrates that the as-prepared Ni-Co-P film is an efficient and robust catalyst with a faradaic efficiency close to 100%. Systematic characterization suggests that the unique hierarchical structure and the mutual participation of nano-sized Ni/Co based components are responsible for the high HER catalytic activity.

Place, publisher, year, edition, pages
ROYAL SOC CHEMISTRY, 2017
National Category
Chemical Sciences
Identifiers
urn:nbn:se:kth:diva-206680 (URN)10.1039/c7ta01716b (DOI)000399390300036 ()2-s2.0-85017596277 (Scopus ID)
Note

QC 20170510

Available from: 2017-05-10 Created: 2017-05-10 Last updated: 2017-05-10Bibliographically approved
Hou, J., Sun, Y., Cao, S., Wu, Y., Chen, H. & Sun, L. (2017). Graphene Dots Embedded Phosphide Nanosheet-Assembled Tubular Arrays for Efficient and Stable Overall Water Splitting. ACS Applied Materials and Interfaces, 9(29), 24600-24607
Open this publication in new window or tab >>Graphene Dots Embedded Phosphide Nanosheet-Assembled Tubular Arrays for Efficient and Stable Overall Water Splitting
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2017 (English)In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 9, no 29, p. 24600-24607Article in journal (Refereed) Published
Abstract [en]

Bifunctional electrocatalysts are highly desired for overall water splitting. Herein, the design and fabrication of three-dimensional (3D) hierarchical earth-abundant transition bimetallic phosphide arrays constructed by one-dimensional tubular array that was derived from assembling two-dimensional nanosheet framework has been reported by tailoring the Co/Ni ratio and tunable morphologies, and zero-dimensional (0D) graphene dots were embedded on Co-Ni phosphide matrix to construct 0D/2D tubular array as a highly efficient electrode in the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). On the basis of advanced merits, such as the high surface-active sites, well-dispersed graphene dots, and enhanced electron transfer capacity as well as the confinement effect of the graphene dots on the nanosheets, the integrated GDs/Co0.8Ni0.2P tubular arrays as anode and cathode exhibit excellent OER and HER performance. By use of GDs/Co0.8Ni0.2 arrays in the two-electrode setup of the device, a remarkable electrocatalytic performance for full water splitting has been achieved with a high current density of 10 mA cm-2 at 1.54 V and outstanding long-term operation stability in an alkaline environment, indicating a promising system based on nonprecious-metal electrocatalysts toward potential practical devices of overall water splitting.

Place, publisher, year, edition, pages
AMER CHEMICAL SOC, 2017
Keywords
graphene dots, transition bimetallic phosphide, oxygen evolution reaction, hydrogen evolution reaction, overall water splitting
National Category
Other Chemical Engineering
Identifiers
urn:nbn:se:kth:diva-212343 (URN)10.1021/acsami.7b06231 (DOI)000406646300025 ()2-s2.0-85026310371 (Scopus ID)
Note

QC 20170823

Available from: 2017-08-23 Created: 2017-08-23 Last updated: 2017-08-23Bibliographically approved
Fan, K., Ji, Y., Zou, H., Zhang, J., Zhu, B., Chen, H., . . . Sun, L. (2017). Hollow Iron-Vanadium Composite Spheres: A Highly Efficient Iron-Based Water Oxidation Electrocatalyst without the Need for Nickel or Cobalt. Angewandte Chemie International Edition, 56(12), 3289-3293
Open this publication in new window or tab >>Hollow Iron-Vanadium Composite Spheres: A Highly Efficient Iron-Based Water Oxidation Electrocatalyst without the Need for Nickel or Cobalt
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2017 (English)In: Angewandte Chemie International Edition, ISSN 1433-7851, E-ISSN 1521-3773, Vol. 56, no 12, p. 3289-3293Article in journal (Refereed) Published
Abstract [en]

Noble-metal-free bimetal-based electrocatalysts have shown high efficiency for water oxidation. Ni and/or Co in these electrocatalysts are essential to provide a conductive, high-surface area and a chemically stable host. However, the necessity of Ni or Co limits the scope of low-cost electrocatalysts. Herein, we report a hierarchical hollow FeV composite, which is Ni- and Co-free and highly efficient for electrocatalytic water oxidation with low overpotential 390 mV (10 mA cm(-2) catalytic current density), low Tafel slope of 36.7 mV dec(-1), and a considerable durability. This work provides a novel and efficient catalyst, and greatly expands the scope of low-cost Fe-based electrocatalysts for water splitting without need of Ni or Co.

Place, publisher, year, edition, pages
WILEY-V C H VERLAG GMBH, 2017
Keywords
electrocatalysts, iron composites, overpotential, vanadium, water oxidation
National Category
Organic Chemistry
Identifiers
urn:nbn:se:kth:diva-205044 (URN)10.1002/anie.201611863 (DOI)000397329300029 ()28194910 (PubMedID)
Note

QC 20170519

Available from: 2017-05-19 Created: 2017-05-19 Last updated: 2017-05-19Bibliographically approved
Daniel, Q., Anabre, R. B., Zhang, B., Philippe, B., Chen, H., Li, F., . . . Sun, L. (2017). Re-Investigation of Cobalt Porphyrin for Electrochemical Water Oxidation on FTO Surface: Formation of CoOx as Active Species. ACS Catalysis, 7(2), 1143-1149
Open this publication in new window or tab >>Re-Investigation of Cobalt Porphyrin for Electrochemical Water Oxidation on FTO Surface: Formation of CoOx as Active Species
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2017 (English)In: ACS Catalysis, ISSN 2155-5435, E-ISSN 2155-5435, Vol. 7, no 2, p. 1143-1149Article in journal (Refereed) Published
Abstract [en]

The use of cobalt porphyrin complexes as efficient and cost-effective molecular catalysts for water oxidation has been investigated previously. However, by combining a set of analytical techniques (electrochemistry, ultraviolet-visible spectroscopy (UV-vis), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and synchrotron-based photoelectron spectroscopy (SOXPES and HAXPES)), we have demonstrated that three different cobalt porphyrins, deposited on FTO glasses, decompose promptly into a thin film of CoOx on the surface of the electrode during water oxidation under certain conditions (borate buffer pH 9.2). It is presumed that the film is composed of CoO, only detectable by SOXPES, as conventional techniques are ineffective. This newly formed film has a high turnover frequency (TOF), while the high transparency of the CoOx-based electrode is very promising for future application in photoelectrochemical cells.

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2017
Keywords
water oxidation, cobalt oxide, decomposition, surface characterization, thin film
National Category
Chemical Sciences
Identifiers
urn:nbn:se:kth:diva-203830 (URN)10.1021/acscatal.6b01815 (DOI)000393539200026 ()2-s2.0-85012893978 (Scopus ID)
Note

QC 20170321

Available from: 2017-03-21 Created: 2017-03-21 Last updated: 2017-11-29Bibliographically approved
Fan, T., Duan, L., Huang, P., Chen, H., Daniel, Q., Ahlquist, M. S. G. & Sun, L. (2017). The Ru-tpc Water Oxidation Catalyst and Beyond: Water Nucleophilic Attack Pathway versus Radical Coupling Pathway.. ACS Catalysis, 7(4), 2956-2966
Open this publication in new window or tab >>The Ru-tpc Water Oxidation Catalyst and Beyond: Water Nucleophilic Attack Pathway versus Radical Coupling Pathway.
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2017 (English)In: ACS Catalysis, ISSN 2155-5435, E-ISSN 2155-5435, Vol. 7, no 4, p. 2956-2966Article in journal (Refereed) Published
Abstract [en]

Many Ru water oxidation catalysts have been documented in the literature. However, only a few can catalyze the O-O bond formation via the radical coupling pathway, while most go through the water nucleophilic attack pathway. Understanding the electronic effect on the reaction pathway is of importance in design of active water oxidation catalysts. The Ru-bda (bda = 2,2'-bipyridine-6,6'-dicarboxylate) catalyst is one example that catalyzes the 0-0 bond formation via the radical coupling pathway. Herein, we manipulate the equatorial backbone ligand, change the doubly charged bda(2-) ligand to a singly charged tpc- (2,2':6',2 ''-terpyridine-6-carboxylate) ligand, and study the structure activity relationship. Surprisingly, kinetics measurements revealed that the resulting Ru-tpc catalyst catalyzes water oxidation via the water nucleophilic attack pathway, which is different from the Ru-bda catalyst. The O-O bond formation Gibbs free energy of activation (AGO) at T = 298.15 K was 20.2 +/- 1.7 kcal mol(-1). The electronic structures of a series of Ru-v=O species were studied by density function theory calculations, revealing that the spin density of O-Ru=O of Ru-v=O is largely dependent on the surrounding ligands. Seven coordination configuration significantly enhances the radical character of Ru-v=O.

Place, publisher, year, edition, pages
AMER CHEMICAL SOC, 2017
Keywords
water oxidation, ruthenium complex, artificial photosynthesis, DFT calculation, water splitting
National Category
Chemical Sciences
Identifiers
urn:nbn:se:kth:diva-206688 (URN)10.1021/acscatal.6b03393 (DOI)000398986700082 ()
Note

QC 20170509

Available from: 2017-05-09 Created: 2017-05-09 Last updated: 2017-05-09Bibliographically approved
Wang, L., Fan, K., Chen, H., Daniel, Q., Philippe, B., Rensmo, H. & Sun, L. (2017). Towards efficient and robust anodes for water splitting: Immobilization of Ru catalysts on carbon electrode and hematite by in situ polymerization. Catalysis Today, 290, 73-77
Open this publication in new window or tab >>Towards efficient and robust anodes for water splitting: Immobilization of Ru catalysts on carbon electrode and hematite by in situ polymerization
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2017 (English)In: Catalysis Today, ISSN 0920-5861, E-ISSN 1873-4308, Vol. 290, p. 73-77Article in journal (Refereed) Published
Abstract [en]

Ru-bda based molecular water oxidation catalysts 1 and 2 (H(2)bda = 2,2'-bipyridine-6,6'-dicarboxylic acid) containing a thiophene group are attached to the surfaces of electrodes by the method of electropolymerization. The Ru-bda molecular catalyst functionalized graphite carbon electrode can catalyze water oxidation efficiently under a overpotential of ca 500 mV to obtain current density of 5 mA cm(-2); and the similarly functionalized photoelectrode based on alpha-Fe2O3 (hematite) film can work as an photoanode for light driven water splitting.

Place, publisher, year, edition, pages
ELSEVIER SCIENCE BV, 2017
Keywords
Water oxidation, Electrochemistry, Molecular catalyst, Polymerization, alpha-Fe2O3
National Category
Chemical Sciences
Identifiers
urn:nbn:se:kth:diva-210455 (URN)10.1016/j.cattod.2016.07.011 (DOI)000402706700011 ()2-s2.0-85008391610 (Scopus ID)
Funder
Swedish Research CouncilKnut and Alice Wallenberg FoundationSwedish Energy Agency
Note

QC 20170706

Available from: 2017-07-06 Created: 2017-07-06 Last updated: 2017-10-09Bibliographically approved
Zhuang, Z., Chen, H., Lin, Z. & Dang, Z. (2016). Mn2O3 hollow spheres synthesized based on an ion-exchange strategy from amorphous calcium carbonate for highly efficient trace-level uranyl extraction. ENVIRONMENTAL SCIENCE-NANO, 3(6), 1254-1258
Open this publication in new window or tab >>Mn2O3 hollow spheres synthesized based on an ion-exchange strategy from amorphous calcium carbonate for highly efficient trace-level uranyl extraction
2016 (English)In: ENVIRONMENTAL SCIENCE-NANO, ISSN 2051-8153, Vol. 3, no 6, p. 1254-1258Article in journal (Refereed) Published
Abstract [en]

Well-defined hierarchical hollow spheres constructed from Mn2O3 quantum dots were prepared via an ion-exchange strategy starting from small-sized amorphous calcium carbonate. They show outstanding capability to extract trace-level uranyl from field water.

Place, publisher, year, edition, pages
Royal Society of Chemistry, 2016
National Category
Chemical Sciences
Identifiers
urn:nbn:se:kth:diva-200791 (URN)10.1039/c6en00411c (DOI)000391423400003 ()2-s2.0-85000415126 (Scopus ID)
Note

QC 20170203

Available from: 2017-02-03 Created: 2017-02-02 Last updated: 2017-02-03Bibliographically approved
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