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Koshki MS, Zirak M, Kazemi M, Alehdaghi H, Baghayeri M, Nodehi M, Rabiee N. Molybdenum-doped BiVO 4 thin films: Facile preparation via hot-spin coating method and the relationship between surface statistical parameters and photoelectrochemical activity. CHEMOSPHERE 2024; 346:140579. [PMID: 38303391 DOI: 10.1016/j.chemosphere.2023.140579] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2023] [Revised: 10/13/2023] [Accepted: 10/26/2023] [Indexed: 02/03/2024]
Abstract
Molybdenum-doped BiVO4 thin films were uniformly coated on indium-doped tin oxide (ITO) substrates via a facile modified hot spin coating (HSC) technique. The prepared layers were used as photoanode in a photoelectrochemical (PEC) cell. Different percentage of Mo dopant was examined to maximize the photo-current density (J) of the layers. The highest J value (872 ± 8 μA/cm2) was obtained by 5 atomic% of Mo doping. After that, the surface topographies of these samples were changed by varying the initial precursor concentration from 27 to 80 mM. The relation between surface topographies and the PEC activity of Mo-doped BiVO4 thin films was investigated from microscopic point of view by calculating the surface roughness exponent of α, and a mechanism for the PEC activity of Mo-doped BiVO4 photoanodes was proposed accordingly. The sample with a small roughness exponent provided a surface with jagged microscopic fluctuations which may trap the air molecules between the electrolyte and sample surface, hindering the fine atomic interaction for photo-generated electron-hole transition. Therefore, the layer with the highest roughness exponent (2α = 0.48 ± 0.03), which means the smoother microscopic surface and better interfacial contact with the electrolyte, exhibited the best PEC activity.
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Affiliation(s)
- Mina-Sadat Koshki
- Department of Chemistry, Faculty of Science, Hakim Sabzevari University, P. O. Box 397, Sabzevar, Iran
| | - Mohammad Zirak
- Department of Physics, Faculty of Science, Hakim Sabzevari University, P. O. Box 397, Sabzevar, Iran.
| | - Maziyar Kazemi
- Department of Physics, Faculty of Science, Hakim Sabzevari University, P. O. Box 397, Sabzevar, Iran
| | - Hassan Alehdaghi
- Department of Physics, Faculty of Science, Hakim Sabzevari University, P. O. Box 397, Sabzevar, Iran
| | - Mehdi Baghayeri
- Department of Chemistry, Faculty of Science, Hakim Sabzevari University, P. O. Box 397, Sabzevar, Iran; Department of Natural Sciences, Lebanese American University, Beirut, Lebanon
| | - Marzieh Nodehi
- Department of Chemistry, Faculty of Science, Hakim Sabzevari University, P. O. Box 397, Sabzevar, Iran
| | - Navid Rabiee
- School of Engineering, Macquarie University, Sydney, NSW, 2109, Australia.
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Gao RT, Nguyen NT, Nakajima T, He J, Liu X, Zhang X, Wang L, Wu L. Dynamic semiconductor-electrolyte interface for sustainable solar water splitting over 600 hours under neutral conditions. SCIENCE ADVANCES 2023; 9:eade4589. [PMID: 36598972 PMCID: PMC9812387 DOI: 10.1126/sciadv.ade4589] [Citation(s) in RCA: 23] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Photoelectrochemical (PEC) water splitting that functions in pH-neutral electrolyte attracts increasing attention to energy demand sustainability. Here, we propose a strategy to in situ form a NiB layer by tuning the composition of the neutral electrolyte with the additions of nickel and borate species, which improves the PEC performance of the BiVO4 photoanode. The NiB/BiVO4 exhibits a photocurrent density of 6.0 mA cm-2 at 1.23 VRHE with an onset potential of 0.2 VRHE under 1 sun illumination. The photoanode displays a photostability of over 600 hours in a neutral electrolyte. The additive of Ni2+ in the electrolyte, which efficiently inhibits the dissolution of NiB, can accelerate the photogenerated charge transfer and enhance the water oxidation kinetics. The borate species with B─O bonds act as a promoter of catalyst activity by accelerating proton-coupled electron transfer. The synergy effect of both species suppresses the surface charge recombination and inhibits the photocorrosion of BiVO4.
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Affiliation(s)
- Rui-Ting Gao
- College of Chemistry and Chemical Engineering, Inner Mongolia University, Hohhot 010021, China
| | - Nhat Truong Nguyen
- Department of Chemical and Materials Engineering, Gina Cody School of Engineering and Computer Science, Concordia University, Montreal QC H3G 2W1, Canada
| | - Tomohiko Nakajima
- Advanced Manufacturing Research Institute, National Institute of Advanced Industrial Science and Technology, Tsukuba Central 5, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565, Japan
| | - Jinlu He
- College of Chemistry and Chemical Engineering, Inner Mongolia University, Hohhot 010021, China
- Corresponding author. (L.Wa.); (J.H.); (L.Wu.)
| | - Xianhu Liu
- Key Laboratory of Materials Processing and Mold, Ministry of Education, Zhengzhou University, Zhengzhou 450002, China
| | - Xueyuan Zhang
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, China
| | - Lei Wang
- College of Chemistry and Chemical Engineering, Inner Mongolia University, Hohhot 010021, China
- Corresponding author. (L.Wa.); (J.H.); (L.Wu.)
| | - Limin Wu
- College of Chemistry and Chemical Engineering, Inner Mongolia University, Hohhot 010021, China
- Department of Materials Science and State Key Laboratory of Molecular Engineering of Polymers, Fudan University, Shanghai 200433, China
- Corresponding author. (L.Wa.); (J.H.); (L.Wu.)
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Kunzelmann VF, Jiang CM, Ihrke I, Sirotti E, Rieth T, Henning A, Eichhorn J, Sharp ID. Solution-based synthesis of wafer-scale epitaxial BiVO 4 thin films exhibiting high structural and optoelectronic quality. JOURNAL OF MATERIALS CHEMISTRY. A 2022; 10:12026-12034. [PMID: 35757488 PMCID: PMC9172877 DOI: 10.1039/d1ta10732a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Accepted: 03/14/2022] [Indexed: 06/15/2023]
Abstract
We demonstrate a facile approach to solution-based synthesis of wafer-scale epitaxial bismuth vanadate (BiVO4) thin films by spin-coating on yttria-stabilized zirconia. Epitaxial growth proceeds via solid-state transformation of initially formed polycrystalline films, driven by interface energy minimization. The (010)-oriented BiVO4 films are smooth and compact, possessing remarkably high structural quality across complete 2'' wafers. Optical absorption is characterized by a sharp onset with a low sub-band gap response, confirming that the structural order of the films results in correspondingly high optoelectronic quality. This combination of structural and optoelectronic quality enables measurements that reveal a strong optical anisotropy of BiVO4, which leads to significantly increased in-plane optical constants near the fundamental band edge that are of particular importance for maximizing light harvesting in semiconductor photoanodes. Temperature-dependent transport measurements confirm a thermally activated hopping barrier of ∼570 meV, consistent with small electron polaron conduction. This simple approach for synthesis of high-quality epitaxial BiVO4, without the need for complex deposition equipment, enables a broadly accessible materials base to accelerate research aimed at understanding and optimizing photoelectrochemical energy conversion mechanisms.
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Affiliation(s)
- Viktoria F Kunzelmann
- Walter Schottky Institute and Physics Department, Technische Universität München Am Coulombwall 4 85748 Garching Germany
| | - Chang-Ming Jiang
- Walter Schottky Institute and Physics Department, Technische Universität München Am Coulombwall 4 85748 Garching Germany
| | - Irina Ihrke
- Walter Schottky Institute and Physics Department, Technische Universität München Am Coulombwall 4 85748 Garching Germany
| | - Elise Sirotti
- Walter Schottky Institute and Physics Department, Technische Universität München Am Coulombwall 4 85748 Garching Germany
| | - Tim Rieth
- Walter Schottky Institute and Physics Department, Technische Universität München Am Coulombwall 4 85748 Garching Germany
| | - Alex Henning
- Walter Schottky Institute and Physics Department, Technische Universität München Am Coulombwall 4 85748 Garching Germany
| | - Johanna Eichhorn
- Walter Schottky Institute and Physics Department, Technische Universität München Am Coulombwall 4 85748 Garching Germany
| | - Ian D Sharp
- Walter Schottky Institute and Physics Department, Technische Universität München Am Coulombwall 4 85748 Garching Germany
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Lyle H, Singh S, Paolino M, Vinogradov I, Cuk T. The electron-transfer intermediates of the oxygen evolution reaction (OER) as polarons by in situ spectroscopy. Phys Chem Chem Phys 2021; 23:24984-25002. [PMID: 34514488 DOI: 10.1039/d1cp01760h] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The conversion of diffusive forms of energy (electrical and light) into short, compact chemical bonds by catalytic reactions regularly involves moving a carrier from an environment that favors delocalization to one that favors localization. While delocalization lowers the energy of the carrier through its kinetic energy, localization creates a polarization around the carrier that traps it in a potential energy minimum. The trapped carrier and its local distortion-termed a polaron in solids-can play a role as a highly reactive intermediate within energy-storing catalytic reactions but is rarely discussed as such. Here, we present this perspective of the polaron as a catalytic intermediate through recent in situ and time-resolved spectroscopic investigations of photo-triggered electrochemical reactions at material surfaces. The focus is on hole-trapping at metal-oxygen bonds, denoted M-OH*, in the context of the oxygen evolution reaction (OER) from water. The potential energy surface for the hole-polaron defines the structural distortions from the periodic lattice and the resulting "active" site of catalysis. This perspective will highlight how current and future time-resolved, multi-modal probes can use spectroscopic signatures of M-OH* polarons to obtain kinetic and structural information on the individual reaction steps of OER. A particular motivation is to provide the background needed for eventually relating this information to relevant catalytic descriptors by free energies. Finally, the formation of the O-O chemical bond from the consumption of M-OH*, required to release O2 and store energy in H2, will be discussed as the next target for experimental investigations.
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Affiliation(s)
- Hanna Lyle
- Renewable and Sustainable Energy Institute (RASEI), University of Colorado, Boulder, 80303, USA. .,Materials Science and Engineering Program, University of Colorado, Boulder, 80303, USA
| | - Suryansh Singh
- Renewable and Sustainable Energy Institute (RASEI), University of Colorado, Boulder, 80303, USA. .,Materials Science and Engineering Program, University of Colorado, Boulder, 80303, USA
| | - Michael Paolino
- Renewable and Sustainable Energy Institute (RASEI), University of Colorado, Boulder, 80303, USA. .,Department of Physics, University of Colorado, Boulder, 80303, USA
| | - Ilya Vinogradov
- Renewable and Sustainable Energy Institute (RASEI), University of Colorado, Boulder, 80303, USA.
| | - Tanja Cuk
- Renewable and Sustainable Energy Institute (RASEI), University of Colorado, Boulder, 80303, USA. .,Department of Chemistry, University of Colorado, Boulder, 80303, USA
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Eichhorn J, Jiang CM, Cooper JK, Sharp ID, Toma FM. Nanoscale Heterogeneities and Composition-Reactivity Relationships in Copper Vanadate Photoanodes. ACS APPLIED MATERIALS & INTERFACES 2021; 13:23575-23583. [PMID: 33998233 DOI: 10.1021/acsami.1c01848] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The photoelectrochemical performance of thin film photoelectrodes can be impacted by deviations from the stoichiometric composition, both at the macroscale and at the nanoscale. This issue is especially pronounced for the class of ternary compounds that are currently investigated for simultaneously achieving the optoelectronic characteristics and chemical stability required for solar fuel generation. Here, we combine macroscopic photoelectrochemical testing with atomic force microscopy (AFM) and scanning transmission X-ray microscopy (STXM) to reveal relationships between photoelectrochemical activity, nanoscale morphology, and local chemical composition in copper vanadate (CVO) thin films as a model system. For films with varying Cu/(Cu + V) ratios around the ideal stoichiometry of stoiberite Cu5V2O10, AFM resolves submicrometer morphology variations, which correlate with variations of the Cu content resolved by STXM. Both stoichiometric and Cu-deficient films exhibit a clear photoresponse, which indicates electronic tolerance to reduced Cu content. While both films exhibit homogeneous O and V content, they are also characterized by local regions of Cu enrichment and depletion that extend beyond individual grains. By contrast, Cu-rich photoelectrodes exhibit a tendency toward CuO secondary phase formation and a significantly reduced photoelectrochemical activity, indicating a significantly poor electronic tolerance to Cu-enrichment. These findings highlight that the average film composition at the macroscale is insufficient for defining structure-function relationships in complex ternary compounds. Rather, correlating microscopic variations in chemical composition to macroscopic photoelectrochemical performance provides insights into photocatalytic activity and stability that are otherwise not apparent from pure macroscopic characterization.
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Affiliation(s)
- Johanna Eichhorn
- Chemical Sciences Division and Joint Center for Artificial Photosynthesis, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720, United States
- Walter Schottky Institute and Physics Department, Technische Universität München, Am Coulombwall 4, 85748 Garching, Germany
| | - Chang-Ming Jiang
- Chemical Sciences Division and Joint Center for Artificial Photosynthesis, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720, United States
- Walter Schottky Institute and Physics Department, Technische Universität München, Am Coulombwall 4, 85748 Garching, Germany
| | - Jason K Cooper
- Chemical Sciences Division and Joint Center for Artificial Photosynthesis, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720, United States
| | - Ian D Sharp
- Walter Schottky Institute and Physics Department, Technische Universität München, Am Coulombwall 4, 85748 Garching, Germany
| | - Francesca M Toma
- Chemical Sciences Division and Joint Center for Artificial Photosynthesis, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720, United States
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