1
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Xiong F, Hu H, Xue X, Wu M, Zhou J, Zhang W, Li R. Sandwich-structured continuous ZIF-8/Ti 3C 2 MXene/ZIF-8 for efficient sterilization: Enhanced photocatalytic activity, photothermal effect, and environmental safety. WATER RESEARCH 2024; 259:121888. [PMID: 38870890 DOI: 10.1016/j.watres.2024.121888] [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: 02/22/2024] [Revised: 05/28/2024] [Accepted: 06/03/2024] [Indexed: 06/15/2024]
Abstract
The development of effective water purification systems is crucial for controlling and remediating environmental pollution, especially in terms of sterilization. Herein, we demonstrate elaborately designed composite nanosheets with a sandwich structure, composed of two-dimensional (2D) Ti3C2 MXene nanosheet core and conformal ZIF-8 ultrathin outer layers, and their potential applications in photocatalytic sterilization. The study results indicate that the conformal ZIF-8-MXene nanosheet exhibits an expanded light absorption range (826 nm), improved photothermal conversion efficiency (6.2 °C s-1), and photocurrent response, thus boosting photocatalytic sterilization efficiency (6.63 log10 CFU mL-1) against Escherichia coli under simulated sunlight within 90 min. Interestingly, 2D ZIF-8 layers exhibit positive zeta potential (19 mV), good hydrophilicity (40.6°), and local photogenerated-hole accumulation, possessing efficient bacteria-trapping efficiency. Membrane filters fabricated from optimized composite nanosheets exhibit an outstanding bacteria-trapping and sterilization efficiency (almost 100 %) against Escherichia coli under simulated sunlight within 30 min of the flow photocatalytic experiments. This work not only presents a rational structural design of the conformal and ultrathin anchoring of ZIF-8 onto a 2D conductive material for bacteria-trapping and sterilization, but also opens new opportunities for using metal-organic frameworks in photocatalytic disinfection of drinking water.
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Affiliation(s)
- Furong Xiong
- College of Materials Science and Engineering, Zhejiang University of Technology, Hangzhou 310014, China
| | - Huilin Hu
- College of Environment, Zhejiang University of Technology, Hangzhou 310014, China
| | - Xiang Xue
- College of Environment, Zhejiang University of Technology, Hangzhou 310014, China
| | - Minqi Wu
- College of Environment, Zhejiang University of Technology, Hangzhou 310014, China
| | - Jiajie Zhou
- College of Environment, Zhejiang University of Technology, Hangzhou 310014, China
| | - Wang Zhang
- College of Materials Science and Engineering, Zhejiang University of Technology, Hangzhou 310014, China.
| | - Rui Li
- College of Environment, Zhejiang University of Technology, Hangzhou 310014, China.
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2
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Cui J, Daboczi M, Cui Z, Gong M, Flitcroft J, Skelton J, Parker SC, Eslava S. BiVO 4 Photoanodes Enhanced with Metal Phosphide Co-Catalysts: Relevant Properties to Boost Photoanode Performance. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2024; 20:e2306757. [PMID: 37803928 DOI: 10.1002/smll.202306757] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2023] [Revised: 09/05/2023] [Indexed: 10/08/2023]
Abstract
Achieving highly performant photoanodes for oxygen evolution is key to developing photoelectrochemical devices for solar water splitting. In this work, BiVO4 photoanodes are enhanced with a series of core-shell structured bimetallic nickel-cobalt phosphides (MPs), and key insights into the role of co-catalysts are provided. The best BiVO4 /Ni1.5 Co0.5 P and BiVO4 /Ni0.5 Co1.5 P photoanodes achieve a 3.5-fold increase in photocurrent compared with bare BiVO4 . It is discovered that this enhanced performance arises from a synergy between work function, catalytic activity, and capacitive ability of the MPs. Distribution of relaxation times analysis reveals that the contact between the MPs, BiVO4 , and the electrolyte gives rise to three routes for hole injection into the electrolyte, all of which are significantly improved by the presence of a second metal cation in the co-catalyst. Kinetic studies demonstrate that the significantly improved interfacial charge injection is due to a lower charge-transfer resistance, enhanced oxygen-evolution reaction kinetics, and larger surface hole concentrations, providing deeper insights into the carrier dynamics in these photoanode/co-catalyst systems for their rational design.
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Affiliation(s)
- Junyi Cui
- Department of Chemical Engineering and Centre for Processable Electronics, Imperial College London, London, SW7 2AZ, UK
| | - Matyas Daboczi
- Department of Chemical Engineering and Centre for Processable Electronics, Imperial College London, London, SW7 2AZ, UK
| | - Zhenyu Cui
- Chu Kochen Honors College, Zhejiang University, Hangzhou, 310058, China
| | - Mengjun Gong
- Department of Chemistry, Molecular Sciences Research Hub, Imperial College London, London, W12 0BZ, UK
| | - Joseph Flitcroft
- Department of Chemistry, University of Manchester, Manchester, M13 9PL, UK
| | - Jonathan Skelton
- Department of Chemistry, University of Manchester, Manchester, M13 9PL, UK
| | | | - Salvador Eslava
- Department of Chemical Engineering and Centre for Processable Electronics, Imperial College London, London, SW7 2AZ, UK
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3
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Su S, Siretanu I, van den Ende D, Mei B, Mul G, Mugele F. Nanometer-Resolved Operando Photo-Response of Faceted BiVO 4 Semiconductor Nanoparticles. J Am Chem Soc 2024; 146:2248-2256. [PMID: 38214667 PMCID: PMC10811660 DOI: 10.1021/jacs.3c12666] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2023] [Revised: 01/03/2024] [Accepted: 01/04/2024] [Indexed: 01/13/2024]
Abstract
Photo(electro)catalysis with semiconducting nanoparticles (NPs) is an attractive approach to convert abundant but intermittent renewable electricity into stable chemical fuels. However, our understanding of the microscopic processes governing the performance of the materials has been hampered by the lack of operando characterization techniques with sufficient lateral resolution. Here, we demonstrate that the local surface potentials of NPs of bismuth vanadate (BiVO4) and their response to illumination differ between adjacent facets and depend strongly on the pH of the ambient electrolyte. The isoelectric points of the dominant {010} basal plane and the adjacent {110} side facets differ by 1.5 pH units. Upon illumination, both facets accumulate positive charges and display a maximum surface photoresponse of +55 mV, much stronger than reported in the literature for the surface photo voltage of BiVO4 NPs in air. High resolution images reveal the presence of numerous surface defects ranging from vacancies of a few atoms, to single unit cell steps, to microfacets of variable orientation and degree of disorder. These defects typically carry a highly localized negative surface charge density and display an opposite photoresponse compared to the adjacent facets. Strategies to model and optimize the performance of photocatalyst NPs, therefore, require an understanding of the distribution of surface defects, including the interaction with ambient electrolyte.
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Affiliation(s)
- Shaoqiang Su
- Physics
of Complex Fluids Group and MESA+ Institute, Faculty of Science and
Technology, University of Twente, P.O. Box 217, Enschede 7500 AE, The
Netherlands
| | - Igor Siretanu
- Physics
of Complex Fluids Group and MESA+ Institute, Faculty of Science and
Technology, University of Twente, P.O. Box 217, Enschede 7500 AE, The
Netherlands
| | - Dirk van den Ende
- Physics
of Complex Fluids Group and MESA+ Institute, Faculty of Science and
Technology, University of Twente, P.O. Box 217, Enschede 7500 AE, The
Netherlands
| | - Bastian Mei
- Photocatalytic
Synthesis Group and MESA+ Institute, Faculty of Science and Technology, University of Twente, P.O. Box 217, Enschede 7500 AE, The Netherlands
| | - Guido Mul
- Photocatalytic
Synthesis Group and MESA+ Institute, Faculty of Science and Technology, University of Twente, P.O. Box 217, Enschede 7500 AE, The Netherlands
| | - Frieder Mugele
- Physics
of Complex Fluids Group and MESA+ Institute, Faculty of Science and
Technology, University of Twente, P.O. Box 217, Enschede 7500 AE, The
Netherlands
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4
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Chen R, Meng L, Xu W, Li L. Cocatalysts-Photoanode Interface in Photoelectrochemical Water Splitting: Understanding and Insights. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2024; 20:e2304807. [PMID: 37653598 DOI: 10.1002/smll.202304807] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Revised: 07/31/2023] [Indexed: 09/02/2023]
Abstract
Sluggish oxygen evolution reactions on photoanode surfaces severely limit the application of photoelectrochemical (PEC) water splitting. The loading of cocatalysts on photoanodes has been recognized as the simplest and most efficient optimization scheme, which can reduce the surface barrier, provide more active sites, and accelerate the surface catalytic reaction kinetics. Nevertheless, the introduction of cocatalysts inevitably generates interfaces between photoanodes and oxygen evolution cocatalysts (Ph/OEC), which causes severe interfacial recombination and hinders the carrier transfer. Recently, many researchers have focused on cocatalyst engineering, while few have investigated the effect of the Ph/OEC interface. Hence, to maximize the advantages of cocatalysts, interfacial problems for designing efficient cocatalysts are systematically introduced. In this review, the interrelationship between the Ph/OEC and PEC performance is classified and some methods for characterizing Ph/OEC interfaces are investigated. Additionally, common interfacial optimization strategies are summarized. This review details cocatalyst-design-based interfacial problems, provides ideas for designing efficient cocatalysts, and offers references for solving interfacial problems.
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Affiliation(s)
- Runyu Chen
- School of Physical Science and Technology, Jiangsu Key Laboratory of Thin Films, Center for Energy Conversion Materials & Physics (CECMP), Soochow University, Suzhou, 215006, P. R. China
| | - Linxing Meng
- School of Physical Science and Technology, Jiangsu Key Laboratory of Thin Films, Center for Energy Conversion Materials & Physics (CECMP), Soochow University, Suzhou, 215006, P. R. China
| | - Weiwei Xu
- School of Physical Science and Technology, Jiangsu Key Laboratory of Thin Films, Center for Energy Conversion Materials & Physics (CECMP), Soochow University, Suzhou, 215006, P. R. China
| | - Liang Li
- School of Physical Science and Technology, Jiangsu Key Laboratory of Thin Films, Center for Energy Conversion Materials & Physics (CECMP), Soochow University, Suzhou, 215006, P. R. China
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5
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Ukraintsev E, Rezek B. Non-contact non-resonant atomic force microscopy method for measurements of highly mobile molecules and nanoparticles. Ultramicroscopy 2023; 253:113816. [PMID: 37531754 DOI: 10.1016/j.ultramic.2023.113816] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Revised: 04/13/2023] [Accepted: 07/25/2023] [Indexed: 08/04/2023]
Abstract
Atomic force microscopy (AFM) is nowadays indispensable versatile scanning probe method widely employed for fundamental and applied research in physics, chemistry, biology as well as industrial metrology. Conventional AFM systems can operate in various environments such as ultra-high vacuum, electrolyte solutions, or controlled gas atmosphere. Measurements in ambient air are prevalent due to their technical simplicity; however, there are drawbacks such as formation of water meniscus that greatly increases attractive interaction (adhesion) between the tip and the sample, reduced spatial resolution, and too strong interactions leading to tip and/or sample modifications. Here we show how the attractive forces in AFM under ambient conditions can be used with advantage to probe surface properties in a very sensitive way even on highly mobile molecules and nanoparticles. We introduce a stable non-contact non-resonant (NCNR) AFM method which enables to reliably perform measurements in the attractive force regime even in air by controlling the tip position in the intimate surface vicinity without touching it. We demonstrate proof-of-concept results on helicene-based macrocycles, DNA on mica, and nanodiamonds on SiO2. We compare the results with other conventional AFM regimes, showing NCNR advantages such as higher spatial resolution, reduced tip contamination, and negligible sample modification. We analyze principle physical and chemical mechanisms influencing the measurements, discuss issues of stability and various possible method implementations. We explain how the NCNR method can be applied in any AFM system by a mere software modification. The method thus opens a new research field for measurements of highly sensitive and mobile nanoscale objects under air and other environments.
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Affiliation(s)
- Egor Ukraintsev
- Faculty of Electrical Engineering, Czech Technical University in Prague, Technická 2, Prague 6, 166 27, Czech Republic.
| | - Bohuslav Rezek
- Faculty of Electrical Engineering, Czech Technical University in Prague, Technická 2, Prague 6, 166 27, Czech Republic
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6
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Zhang Z, Xiang Y, Zhu Z. Electronic Characteristics, Stability and Water Oxidation Selectivity of High-Index BiVO 4 Facets for Photocatalytic Application: A First Principle Study. NANOMATERIALS (BASEL, SWITZERLAND) 2023; 13:2023. [PMID: 37446539 DOI: 10.3390/nano13132023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Revised: 06/26/2023] [Accepted: 07/04/2023] [Indexed: 07/15/2023]
Abstract
Some high-index facets of BiVO4, such as (012), (210), (115), (511), (121), (132) and (231), exhibit much better photocatalytic performance than conventional (010) and (110) surfaces for water splitting. However, the detailed mechanisms and stability of improved photocatalytic performance for these high-index BiVO4 surfaces are still not clear, which is important for designing photocatalysts with high efficiency. Here, based on first principle calculation, we carried out a systematic theoretical research on BiVO4 with different surfaces, especially high-index facets. The results show that all of the high-index facets in our calculated systems show an n-type behavior, and the band edge positions indicate that all of the high-index facets have enough ability to produce O2 without external bias. Electronic structures, band alignments and formation enthalpy indicate that (012), (115) and (132) could be equivalent to (210), (511) and (231), respectively, in the calculation. Oxidation and reduction potential show that only (132)/(231) is stable without strongly oxidative conditions, and the Gibbs free energy indicates that (012)/(210), (115)/(511), (121) and (132)/(231) have lower overpotential than (010) and (110). Our calculation is able to unveil insights into the effects of the surface, including electronic structures, overpotential and stability during the reaction process.
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Affiliation(s)
- Zhiyuan Zhang
- College of Advanced Interdisciplinary Studies & Hunan Provincial Key Laboratory of Novel Nano Optoelectronic Information Materials and Devices, National University of Defense Technology, 410073 Changsha, China
- Nanhu Laser Laboratory, National University of Defense Technology, Changsha 410073, China
| | - Yuqi Xiang
- College of Advanced Interdisciplinary Studies & Hunan Provincial Key Laboratory of Novel Nano Optoelectronic Information Materials and Devices, National University of Defense Technology, 410073 Changsha, China
- Nanhu Laser Laboratory, National University of Defense Technology, Changsha 410073, China
| | - Zhihong Zhu
- College of Advanced Interdisciplinary Studies & Hunan Provincial Key Laboratory of Novel Nano Optoelectronic Information Materials and Devices, National University of Defense Technology, 410073 Changsha, China
- Nanhu Laser Laboratory, National University of Defense Technology, Changsha 410073, China
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7
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Li Y, Liu S, Liu R, Pan J, Li X, Zhang J, Zhang X, Zhao Y, Wang D, Quan H, Zhu S. Nanoarchitectonics on Z-scheme and Mott-Schottky heterostructure for photocatalytic water oxidation via dual-cascade charge-transfer pathways. NANOSCALE ADVANCES 2023; 5:3386-3395. [PMID: 37325531 PMCID: PMC10262966 DOI: 10.1039/d3na00182b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/22/2023] [Accepted: 05/08/2023] [Indexed: 06/17/2023]
Abstract
The bottleneck for water splitting to generate hydrogen fuel is the sluggish oxidation of water. Even though the monoclinic-BiVO4 (m-BiVO4)-based heterostructure has been widely applied for water oxidation, carrier recombination on dual surfaces of the m-BiVO4 component have not been fully resolved by a single heterojunction. Inspired by natural photosynthesis, we established an m-BiVO4/carbon nitride (C3N4) Z-scheme heterostructure based on the m-BiVO4/reduced graphene oxide (rGO) Mott-Schottky heterostructure, constructing the face-contact C3N4/m-BiVO4/rGO (CNBG) ternary composite to remove excessive surface recombination during water oxidation. The rGO can accumulate photogenerated electrons from m-BiVO4 through a high conductivity region over the heterointerface, with the electrons then prone to diffuse along a highly conductive carbon network. In an internal electric field at the heterointerface of m-BiVO4/C3N4, the low-energy electrons and holes are rapidly consumed under irradiation. Therefore, spatial separation of electron-hole pairs occurs, and strong redox potentials are maintained by the Z-scheme electron transfer. These advantages endow the CNBG ternary composite with over 193% growth in O2 yield, and a remarkable rise in ·OH and ·O2- radicals, compared to the m-BiVO4/rGO binary composite. This work shows a novel perspective for rationally integrating Z-scheme and Mott-Schottky heterostructures in the water oxidation reaction.
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Affiliation(s)
- Yao Li
- State Key Laboratory of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University Shanghai 200240 P. R. China
| | - Siyuan Liu
- State Key Laboratory of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University Shanghai 200240 P. R. China
| | - Runlu Liu
- State Key Laboratory of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University Shanghai 200240 P. R. China
| | - Jian Pan
- Particles and Catalysis Research Group, School of Chemical Engineering, University of New South Wales Sydney 2052 Australia
| | - Xin Li
- School of Environmental Science and Engineering, Shanghai Jiao Tong University Shanghai 200240 China
| | - Jianyu Zhang
- State Key Laboratory of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University Shanghai 200240 P. R. China
| | - Xiaoxiao Zhang
- State Key Laboratory of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University Shanghai 200240 P. R. China
| | - Yixin Zhao
- School of Environmental Science and Engineering, Shanghai Jiao Tong University Shanghai 200240 China
| | - Dawei Wang
- Particles and Catalysis Research Group, School of Chemical Engineering, University of New South Wales Sydney 2052 Australia
| | - Hengdao Quan
- School of Chemical Engineering and Environment, Beijing Institute of Technology Beijing 100081 China
| | - Shenmin Zhu
- State Key Laboratory of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University Shanghai 200240 P. R. China
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8
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Munz M, Poon J, Frandsen W, Cuenya BR, Kley CS. Nanoscale Electron Transfer Variations at Electrocatalyst-Electrolyte Interfaces Resolved by in Situ Conductive Atomic Force Microscopy. J Am Chem Soc 2023; 145:5242-5251. [PMID: 36812448 PMCID: PMC9999420 DOI: 10.1021/jacs.2c12617] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2022] [Indexed: 02/24/2023]
Abstract
Rational innovation of electrocatalysts requires detailed knowledge of spatial property variations across the solid-electrolyte interface. We introduce correlative atomic force microscopy (AFM) to simultaneously probe, in situ and at the nanoscale, electrical conductivity, chemical-frictional, and morphological properties of a bimetallic copper-gold system for CO2 electroreduction. In air, water, and bicarbonate electrolyte, current-voltage curves reveal resistive CuOx islands in line with local current contrasts, while frictional imaging indicates qualitative variations in the hydration layer molecular ordering upon change from water to electrolyte. Nanoscale current contrast on polycrystalline Au shows resistive grain boundaries and electrocatalytically passive adlayer regions. In situ conductive AFM imaging in water shows mesoscale regions of low current and reveals that reduced interfacial electric currents are accompanied by increased friction forces, thus indicating variations in the interfacial molecular ordering affected by the electrolyte composition and ionic species. These findings provide insights into how local electrochemical environments and adsorbed species affect interfacial charge transfer processes and support building in situ structure-property relationships in catalysis and energy conversion research.
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Affiliation(s)
- Martin Munz
- Helmholtz
Young Investigator Group Nanoscale Operando CO2 Photo-Electrocatalysis, Helmholtz-Zentrum Berlin für Materialien und
Energie GmbH, 14109 Berlin, Germany
- Department
of Interface Science, Fritz Haber Institute
of the Max Planck Society, 14195 Berlin, Germany
| | - Jeffrey Poon
- Department
of Interface Science, Fritz Haber Institute
of the Max Planck Society, 14195 Berlin, Germany
| | - Wiebke Frandsen
- Department
of Interface Science, Fritz Haber Institute
of the Max Planck Society, 14195 Berlin, Germany
| | - Beatriz Roldan Cuenya
- Department
of Interface Science, Fritz Haber Institute
of the Max Planck Society, 14195 Berlin, Germany
| | - Christopher S. Kley
- Helmholtz
Young Investigator Group Nanoscale Operando CO2 Photo-Electrocatalysis, Helmholtz-Zentrum Berlin für Materialien und
Energie GmbH, 14109 Berlin, Germany
- Department
of Interface Science, Fritz Haber Institute
of the Max Planck Society, 14195 Berlin, Germany
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9
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Delen G, Monai M, Stančiaková K, Baumgartner B, Meirer F, Weckhuysen BM. Structure sensitivity in gas sorption and conversion on metal-organic frameworks. Nat Commun 2023; 14:129. [PMID: 36624095 PMCID: PMC9829675 DOI: 10.1038/s41467-022-35762-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Accepted: 12/22/2022] [Indexed: 01/11/2023] Open
Abstract
Many catalytic processes depend on the sorption and conversion of gaseous molecules on the surface of (porous) functional materials. These events often preferentially occur on specific, undercoordinated, external surface sites. Here we show the combination of in situ Photo-induced Force Microscopy (PiFM) with Density Functional Theory (DFT) calculations to study the site-specific sorption and conversion of formaldehyde on the external surfaces of well-defined faceted ZIF-8 microcrystals with nanoscale resolution. We observed preferential adsorption of formaldehyde on high index planes. Moreover, in situ PiFM allowed us to visualize unsaturated nanodomains within extended external crystal planes, showing enhanced sorption behavior on the nanoscale. Additionally, on defective ZIF-8 crystals, structure sensitive conversion of formaldehyde through a methoxy- and a formate mechanism mediated by Lewis acidity was found. Strikingly, sorption and conversion were influenced more by the external surface termination than by the concentration of defects. DFT calculations showed that this is due to the presence of specific atomic arrangements on high-index crystal surfaces. With this research, we showcase the high potential of in situ PiFM for structure sensitivity studies on porous functional materials.
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Affiliation(s)
- Guusje Delen
- grid.5477.10000000120346234Inorganic Chemistry and Catalysis, Institute for Sustainable and Circular Chemistry and Debye Institute for Nanomaterials Science, Utrecht University, Utrecht, The Netherlands
| | - Matteo Monai
- grid.5477.10000000120346234Inorganic Chemistry and Catalysis, Institute for Sustainable and Circular Chemistry and Debye Institute for Nanomaterials Science, Utrecht University, Utrecht, The Netherlands
| | - Katarina Stančiaková
- grid.5477.10000000120346234Inorganic Chemistry and Catalysis, Institute for Sustainable and Circular Chemistry and Debye Institute for Nanomaterials Science, Utrecht University, Utrecht, The Netherlands
| | - Bettina Baumgartner
- grid.5477.10000000120346234Inorganic Chemistry and Catalysis, Institute for Sustainable and Circular Chemistry and Debye Institute for Nanomaterials Science, Utrecht University, Utrecht, The Netherlands
| | - Florian Meirer
- grid.5477.10000000120346234Inorganic Chemistry and Catalysis, Institute for Sustainable and Circular Chemistry and Debye Institute for Nanomaterials Science, Utrecht University, Utrecht, The Netherlands
| | - Bert M. Weckhuysen
- grid.5477.10000000120346234Inorganic Chemistry and Catalysis, Institute for Sustainable and Circular Chemistry and Debye Institute for Nanomaterials Science, Utrecht University, Utrecht, The Netherlands
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10
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Recent Advances in In Situ/Operando Surface/Interface Characterization Techniques for the Study of Artificial Photosynthesis. INORGANICS 2022. [DOI: 10.3390/inorganics11010016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
(Photo-)electrocatalytic artificial photosynthesis driven by electrical and/or solar energy that converts water (H2O) and carbon dioxide (CO2) into hydrogen (H2), carbohydrates and oxygen (O2), has proven to be a promising and effective route for producing clean alternatives to fossil fuels, as well as for storing intermittent renewable energy, and thus to solve the energy crisis and climate change issues that we are facing today. Basic (photo-)electrocatalysis consists of three main processes: (1) light absorption, (2) the separation and transport of photogenerated charge carriers, and (3) the transfer of photogenerated charge carriers at the interfaces. With further research, scientists have found that these three steps are significantly affected by surface and interface properties (e.g., defect, dangling bonds, adsorption/desorption, surface recombination, electric double layer (EDL), surface dipole). Therefore, the catalytic performance, which to a great extent is determined by the physicochemical properties of surfaces and interfaces between catalyst and reactant, can be changed dramatically under working conditions. Common approaches for investigating these phenomena include X-ray photoelectron spectroscopy (XPS), X-ray absorption spectroscopy (XAS), scanning probe microscopy (SPM), wide angle X-ray diffraction (WAXRD), auger electron spectroscopy (AES), transmission electron microscope (TEM), etc. Generally, these techniques can only be applied under ex situ conditions and cannot fully recover the changes of catalysts in real chemical reactions. How to identify and track alterations of the catalysts, and thus provide further insight into the complex mechanisms behind them, has become a major research topic in this field. The application of in situ/operando characterization techniques enables real-time monitoring and analysis of dynamic changes. Therefore, researchers can obtain physical and/or chemical information during the reaction (e.g., morphology, chemical bonding, valence state, photocurrent distribution, surface potential variation, surface reconstruction), or even by the combination of these techniques as a suite (e.g., atomic force microscopy-based infrared spectroscopy (AFM-IR), or near-ambient-pressure STM/XPS combined system (NAP STM-XPS)) to correlate the various properties simultaneously, so as to further reveal the reaction mechanisms. In this review, we briefly describe the working principles of in situ/operando surface/interface characterization technologies (i.e., SPM and X-ray spectroscopy) and discuss the recent progress in monitoring relevant surface/interface changes during water splitting and CO2 reduction reactions (CO2RR). We hope that this review will provide our readers with some ideas and guidance about how these in situ/operando characterization techniques can help us investigate the changes in catalyst surfaces/interfaces, and further promote the development of (photo-)electrocatalytic surface and interface engineering.
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11
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Zhang Z, Song Y, Xiang Y, Zhu Z. Vacancy defect engineered BiVO 4 with low-index surfaces for photocatalytic application: a first principles study. RSC Adv 2022; 12:31317-31325. [PMID: 36349004 PMCID: PMC9623612 DOI: 10.1039/d2ra04890f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Accepted: 10/18/2022] [Indexed: 06/16/2023] Open
Abstract
BiVO4 has been widely investigated as a photocatalyst material for water splitting due to its outstanding photocatalytic properties. In order to further improve its photocatalytic efficiency, it is necessary to conduct an in-depth study of improvement strategies, such as defect engineering. By focusing on the (001) and (011) surfaces, we carried out a systematic theoretical research on pristine and defective systems, including Bi, V and O vacancies. Based on density functional theory (DFT), the electronic properties, band alignments and Gibbs free energy of pristine and defective BiVO4 have been analyzed. The electronic structures of the (001) and (011) surfaces show different band gaps, and O vacancies make the BiVO4 become an n-type semiconductor, while Bi and V vacancies tend to form a p-type semiconductor. Moreover, the band edge positions indicate that holes are indeed easily accumulated on the (011) surface while electrons tend to accumulate on (001). However, the (011) surface with Bi and V vacancies does not have enough oxidation potential to oxidize water. The reaction free energy shows that O and Bi vacancies could lower the overpotential to some extent.
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Affiliation(s)
- Zhiyuan Zhang
- College of Advanced Interdisciplinary Studies & Hunan Provincial Key Laboratory of Novel Nano Optoelectronic Information Materials and Devices, National University of Defense Technology 410073 Changsha Hunan P. R. China
| | - Yingchao Song
- College of Advanced Interdisciplinary Studies & Hunan Provincial Key Laboratory of Novel Nano Optoelectronic Information Materials and Devices, National University of Defense Technology 410073 Changsha Hunan P. R. China
| | - Yuqi Xiang
- College of Advanced Interdisciplinary Studies & Hunan Provincial Key Laboratory of Novel Nano Optoelectronic Information Materials and Devices, National University of Defense Technology 410073 Changsha Hunan P. R. China
| | - Zhihong Zhu
- College of Advanced Interdisciplinary Studies & Hunan Provincial Key Laboratory of Novel Nano Optoelectronic Information Materials and Devices, National University of Defense Technology 410073 Changsha Hunan P. R. China
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12
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Chen Z, Hoang AT, Hwang W, Seo D, Cho M, Kim YD, Yang L, Soon A, Ahn JH, Choi HJ. Vertical Conductivity and Topography in Electrostrictive Germanium Sulfide Microribbon via Conductive Atomic Force Microscopy. NANO LETTERS 2022; 22:7636-7643. [PMID: 36106948 DOI: 10.1021/acs.nanolett.2c02763] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Layered group IV monochalcogenides are two-dimensional (2D) semiconducting materials with unique crystal structures and novel physical properties. Here, we report the growth of single crystalline GeS microribbons using the chemical vapor transport process. By using conductive atomic force microscopy, we demonstrated that the conductive behavior in the vertical direction was mainly affected by the Schottky barriers between GeS and both electrodes. Furthermore, we found that the topographic and current heterogeneities were significantly different with and without illumination. The topographic deformation and current enhancement were also predicted by our density functional theory (DFT)-based calculations. Their local spatial correlation between the topographic height and current was established. By virtue of 2D fast Fourier transform power spectra, we constructed the holistic spatial correlation between the topographic and current heterogeneity that indicated the diminished correlation with illumination. These findings on layered GeS microribbons provide insights into the conductive and topographic behaviors in 2D materials.
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Affiliation(s)
- Zhangfu Chen
- Department of Materials Science and Engineering, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 03722, Republic of Korea
| | - Anh Tuan Hoang
- School of Electrical and Electronic Engineering, Yonsei University, Seoul 03722, Republic of Korea
| | - Woohyun Hwang
- Department of Materials Science and Engineering, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 03722, Republic of Korea
| | - Dongjea Seo
- Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Minhyun Cho
- Department of Physics, Kyung Hee University, Seoul 02447, Republic of Korea
| | - Young Duck Kim
- Department of Physics, Kyung Hee University, Seoul 02447, Republic of Korea
| | - Lianqiao Yang
- Key Laboratory of Advanced Display and System Applications Ministry of Education, Shanghai University, Yanchang Road 149, Shanghai 200072, China
| | - Aloysius Soon
- Department of Materials Science and Engineering, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 03722, Republic of Korea
| | - Jong-Hyun Ahn
- School of Electrical and Electronic Engineering, Yonsei University, Seoul 03722, Republic of Korea
| | - Heon-Jin Choi
- Department of Materials Science and Engineering, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 03722, Republic of Korea
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13
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Chen R, Fan F, Li C. Unraveling Charge-Separation Mechanisms in Photocatalyst Particles by Spatially Resolved Surface Photovoltage Techniques. Angew Chem Int Ed Engl 2022; 61:e202117567. [PMID: 35100475 DOI: 10.1002/anie.202117567] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Indexed: 11/08/2022]
Abstract
The photocatalytic conversion of solar energy offers a potential route to renewable energy, and its efficiency relies on effective charge separation in nanostructured photocatalysts. Understanding the charge-separation mechanism is key to improving the photocatalytic performance and this has now been enabled by advances in the spatially resolved surface photovoltage (SRSPV) method. In this Review we highlight progress made by SRSPV in mapping charge distributions at the nanoscale and determining the driving forces of charge separation in heterogeneous photocatalyst particles. We discuss how charge separation arising from a built-in electric field, diffusion, and trapping can be exploited and optimized through photocatalyst design. We also highlight the importance of asymmetric engineering of photocatalysts for effective charge separation. Finally, we provide an outlook on further opportunities that arise from leveraging these insights to guide the rational design of photocatalysts and advance the imaging technique to expand the knowledge of charge separation.
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Affiliation(s)
- Ruotian Chen
- State Key Laboratory of Catalysis, Dalian National Laboratory for Clean Energy, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Zhongshan Road 457, Dalian, 116023, China
| | - Fengtao Fan
- State Key Laboratory of Catalysis, Dalian National Laboratory for Clean Energy, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Zhongshan Road 457, Dalian, 116023, China
| | - Can Li
- State Key Laboratory of Catalysis, Dalian National Laboratory for Clean Energy, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Zhongshan Road 457, Dalian, 116023, China
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14
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Liu S, Pan J, Kong W, Li X, Zhang J, Zhang X, Liu R, Li Y, Zhao Y, Wang D, Zhang J, Zhu S. Synergetic Nanoarchitectonics of Defects and Cocatalysts in Oxygen-Vacancy-Rich BiVO 4/reduced graphene oxide Mott-Schottky Heterostructures for Photocatalytic Water Oxidation. ACS APPLIED MATERIALS & INTERFACES 2022; 14:12180-12192. [PMID: 35234436 DOI: 10.1021/acsami.1c22250] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Water oxidation process is a pivotal step of photosynthesis and stimulates the progress of high-performance catalysts for renewable fuel production. Despite the performance benefit of cocatalysts, defect engineering holds promise to settle inherent limitations of semiconductors aiming at sluggish water oxidation. Here, we modify the in situ growth pathway of monoclinic BiVO4 (m-BiVO4) on reduced graphene oxide (rGO), constructing abundant surface oxygen vacancies (OV)-incorporated m-BiVO4/rGO heterostructure toward water oxidation reaction under visible light. Owing to the OV in the m-BiVO4 component, a vacancy-related defect level allows more electrons to be photoexcited by low-energy photons to cause the electron transition, boosting photoabsorption as well as photoexcitation. Besides, the OV can reinforce surface adsorption and reduce the dissociation energy of water molecules. Particularly because of the synergy of OV and cocatalyst rGO, the OV functions as electron-trapped sites to facilitate the carrier separation; the rGO not only receives electrons from m-BiVO4 promoted by internal electric field over Mott-Schottky heterostructures but also spurs further electron diffusion along a highly conductive carbon network. These merits enable the OV-incorporated m-BiVO4/rGO heterostructure with an over 209% growth in O2 yield relative to the counterpart. The increased performance is also validated by the significant rise of •OH radicals and •O2- radicals. The current work paves a novel avenue for the integration of defect engineering and cocatalyst coupling in artificial photosynthesis.
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Affiliation(s)
- Siyuan Liu
- State Key Laboratory of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Jian Pan
- Particles and Catalysis Research Group, School of Chemical Engineering, University of New South Wales, Sydney, New South Wales 2052, Australia
| | - Weiyu Kong
- State Key Laboratory of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Xin Li
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Jianyu Zhang
- State Key Laboratory of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Xiaoxiao Zhang
- State Key Laboratory of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Runlu Liu
- State Key Laboratory of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Yao Li
- State Key Laboratory of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Yixin Zhao
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Dawei Wang
- Particles and Catalysis Research Group, School of Chemical Engineering, University of New South Wales, Sydney, New South Wales 2052, Australia
| | - Jianqin Zhang
- Shanghai Institute of Space Power-Sources, Shanghai 200245, China
| | - Shenmin Zhu
- State Key Laboratory of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
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15
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Chen R, Fan F, Li C. Unraveling Charge‐Separation Mechanisms in Photocatalyst Particles by Spatially Resolved Surface Photovoltage Techniques. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202117567] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Ruotian Chen
- State Key Laboratory of Catalysis Dalian National Laboratory for Clean Energy Dalian Institute of Chemical Physics Chinese Academy of Sciences Zhongshan Road 457 Dalian 116023 China
| | - Fengtao Fan
- State Key Laboratory of Catalysis Dalian National Laboratory for Clean Energy Dalian Institute of Chemical Physics Chinese Academy of Sciences Zhongshan Road 457 Dalian 116023 China
| | - Can Li
- State Key Laboratory of Catalysis Dalian National Laboratory for Clean Energy Dalian Institute of Chemical Physics Chinese Academy of Sciences Zhongshan Road 457 Dalian 116023 China
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16
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Bedoya-Lora FE, Hankin A, Kelsall GH. En Route to a Unified Model for Photoelectrochemical Reactor Optimization. II–Geometric Optimization of Perforated Photoelectrodes. FRONTIERS IN CHEMICAL ENGINEERING 2021. [DOI: 10.3389/fceng.2021.749058] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Results have been reported previously of a model describing the performance of photoelectrochemical reactors, which utilize semiconductor | liquid junctions. This model was developed and verified using SnIV-doped α-Fe2O3 as photoanodes. Hematite films were fully characterized to obtain parameter inputs to a model predicting photocurrent densities. Thus, measured photocurrents were described and validated by the model in terms of measurable quantities. The complete reactor model, developed in COMSOL Multiphysics, accounted for gas evolution and desorption in the system. Hydrogen fluxes, charge yields and gas collection efficiencies in a photoelectrochemical reactor were estimated, revealing a critical need for geometric optimization to minimize H2-O2 product recombination as well as undesirable spatial distributions of current densities and “overpotentials” across the electrodes. Herein, the model was implemented in a 3D geometry and validated using solid and perforated 0.1 × 0.1 m2 planar photoanodes in an up-scaled photoelectrochemical reactor of 2 dm3. The same model was then applied to a set of simulated electrode geometries and electrode configurations to identify the electrode design that would maximize current densities and H2 fluxes. The electrode geometry was modified by introducing circular perforations of different sizes, relative separations and arrangements into an otherwise solid planar sheet for the purpose of providing ionic shortcuts. We report the simulated effects of electrode thickness and the presence or absence of a membrane to separate oxygen and hydrogen gases. In a reactor incorporating a membrane and a photoanode at 1.51 V vs RHE and pH 13.6, an optimized hydrogen flux was predicted for a perforation geometry with a separation-to-diameter ratio of 4.5 ± 0.5; the optimal perforation diameter was 50 µm. For reactors without a membrane, this ratio was 6.5 and 8.5 for a photoanode in a “wired” (monopolar) and “wireless” (photo-bipolar) design, respectively. The results and methodologies presented here will serve as a framework to optimize composite photoelectrodes (semiconductor | membrane | electrolyte), and photoelectrochemical reactors in general, for the production of hydrogen (and oxygen) from water using solar energy.
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17
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Improving Photoelectrochemical Activity of ZnO/TiO2 Core–Shell Nanostructure through Ag Nanoparticle Integration. Catalysts 2021. [DOI: 10.3390/catal11080911] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
In solar energy harvesting using solar cells and photocatalysts, the photoexcitation of electrons and holes in semiconductors is the first major step in the solar energy conversion. The lifetime of carriers, a key factor determining the energy conversion and photocatalysis efficiency, is shortened mainly by the recombination of photoexcited carriers. We prepared and tested a series of ZnO/TiO2-based heterostructures in search of designs which can extend the carrier lifetime. Time-resolved photoluminescence tests revealed that, in ZnO/TiO2 core–shell structure the carrier lifetime is extended by over 20 times comparing with the pure ZnO nanorods. The performance improved further when Ag nanoparticles were integrated at the ZnO/TiO2 interface to construct a Z-scheme structure. We utilized these samples as photoanodes in a photoelectrochemical (PEC) cell and analyzed their solar water splitting performances. Our data showed that these modifications significantly enhanced the PEC performance. Especially, under visible light, the Z-scheme structure generated a photocurrent density 100 times higher than from the original ZnO samples. These results reveal the potential of ZnO-Ag-TiO2 nanorod arrays as a long-carrier-lifetime structure for future solar energy harvesting applications.
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18
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Bhattacharya S, Chandra GK, Predeep P. A Microstructural Analysis of 2D Halide Perovskites: Stability and Functionality. FRONTIERS IN NANOTECHNOLOGY 2021. [DOI: 10.3389/fnano.2021.657948] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Recent observations have demonstrated that the photoelectric conversion properties of perovskite materials are intimately related to the presence of superlattice structures and other unusual nanoscale features in them. The low-dimensional or mixed-dimensional halide perovskite families are found to be more efficient materials for device application than three-dimensional halide perovskites. The emergence of perovskite solar cells has revolutionized the solar cell industry because of their flexible architecture and rapidly increased efficiency. Tuning the dielectric constant and charge separation are the main objectives in designing a photovoltaic device that can be explored using the two-dimensional perovskite family. Thus, revisiting the fundamental properties of perovskite crystals could reveal further possibilities for recognizing these improvements toward device functionality. In this context, this review discusses the material properties of two-dimensional halide perovskites and related optoelectronic devices, aiming particularly for solar cell applications.
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19
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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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20
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Prasad U, Prakash J, Shi X, Sharma SK, Peng X, Kannan AM. Role of Alkali Metal in BiVO 4 Crystal Structure for Enhancing Charge Separation and Diffusion Length for Photoelectrochemical Water Splitting. ACS APPLIED MATERIALS & INTERFACES 2020; 12:52808-52818. [PMID: 33185439 DOI: 10.1021/acsami.0c16519] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Alkali metal (Na or K) doping in BiVO4 was examined systematically for enhancing bulk charge separation and transport in addition to improving charge transfer from the surface. The alkali metal-doped BiVO4 thin film photoanodes having nanostructured porous grain surface morphology exhibited better photocurrent density than pristine BiVO4. In particular, Na:BiVO4/Fe:Ni/Co-Pi photoanode showed a significantly improved photocurrent of 3.2 ± 0.15 mA·cm-2 in 0.1 M K2HPO4 electrolyte at 1.23 VRHE under 1 sun illumination. The depth-dependent Doppler broadening spectroscopy measurements confirmed the significant reduction in Bi- and V-based defect density with Na metal doping, and this led to a higher bulk diffusion length of charge pairs (four times that of the pristine one). Na doping led to reduced surface defects resulting in improved surface charge transfer based on cyclic voltammetry experiments. The density functional theory calculations confirmed the improved performance in Na-doped BiVO4 photoanodes achieved through interband formation and reduction in the band gap.
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Affiliation(s)
- Umesh Prasad
- The Polytechnic School, Ira A. Fulton Schools of Engineering, Arizona State University, Mesa, Arizona 85212, United States
| | - Jyoti Prakash
- Materials Group, Bhabha Atomic Research Centre, Mumbai 400085, India
| | - Xuan Shi
- The Polytechnic School, Ira A. Fulton Schools of Engineering, Arizona State University, Mesa, Arizona 85212, United States
| | - Sandeep K Sharma
- Radiochemistry Division, Bhabha Atomic Research Centre, Mumbai 40085, India
| | - Xihong Peng
- Science and Mathematics, College of Integrative Sciences and Arts, Arizona State University, Mesa, Arizona 85212, United States
| | - Arunachala M Kannan
- The Polytechnic School, Ira A. Fulton Schools of Engineering, Arizona State University, Mesa, Arizona 85212, United States
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21
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Eichhorn J, Reyes-Lillo SE, Roychoudhury S, Sallis S, Weis J, Larson DM, Cooper JK, Sharp ID, Prendergast D, Toma FM. Revealing Nanoscale Chemical Heterogeneities in Polycrystalline Mo-BiVO 4 Thin Films. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2020; 16:e2001600. [PMID: 32755006 DOI: 10.1002/smll.202001600] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Revised: 06/04/2020] [Indexed: 06/11/2023]
Abstract
The activity of polycrystalline thin film photoelectrodes is impacted by local variations of the material properties due to the exposure of different crystal facets and the presence of grain/domain boundaries. Here a multi-modal approach is applied to correlate nanoscale heterogeneities in chemical composition and electronic structure with nanoscale morphology in polycrystalline Mo-BiVO4 . By using scanning transmission X-ray microscopy, the characteristic structure of polycrystalline film is used to disentangle the different X-ray absorption spectra corresponding to grain centers and grain boundaries. Comparing both spectra reveals phase segregation of V2 O5 at grain boundaries of Mo-BiVO4 thin films, which is further supported by X-ray photoelectron spectroscopy and many-body density functional theory calculations. Theoretical calculations also enable to predict the X-ray absorption spectral fingerprint of polarons in Mo-BiVO4 . After photo-electrochemical operation, the degraded Mo-BiVO4 films show similar grain center and grain boundary spectra indicating V2 O5 dissolution in the course of the reaction. Overall, these findings provide valuable insights into the degradation mechanism and the impact of material heterogeneities on the material performance and stability of polycrystalline photoelectrodes.
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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, CA, 94720, USA
- Walter Schottky Institut and Physik Department, Technische Universität München, Am Coulombwall 4, Garching, 85748, Germany
| | | | - Subhayan Roychoudhury
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
- The Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Shawn Sallis
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Johannes Weis
- Chemical Sciences Division and Joint Center for Artificial Photosynthesis, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA, 94720, USA
| | - David M Larson
- Chemical Sciences Division and Joint Center for Artificial Photosynthesis, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA, 94720, USA
| | - Jason K Cooper
- Chemical Sciences Division and Joint Center for Artificial Photosynthesis, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA, 94720, USA
| | - Ian D Sharp
- Chemical Sciences Division and Joint Center for Artificial Photosynthesis, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA, 94720, USA
- Walter Schottky Institut and Physik Department, Technische Universität München, Am Coulombwall 4, Garching, 85748, Germany
| | - David Prendergast
- The Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Francesca M Toma
- Chemical Sciences Division and Joint Center for Artificial Photosynthesis, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA, 94720, USA
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22
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Liu S, Pan J, Li X, Meng X, Yuan H, Li Y, Zhao Y, Wang D, Ma J, Zhu S, Kong L. In situ modification of BiVO 4 nanosheets on graphene for boosting photocatalytic water oxidation. NANOSCALE 2020; 12:14853-14862. [PMID: 32633738 DOI: 10.1039/d0nr02718a] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Owing to the sluggish water oxidation process, unearthing an ideal model for disclosing the impact of an architectural approach on the water oxidation activity of photocatalysts becomes a vital issue. Here, we propose an innovative in situ modification strategy for constructing ultrapure BiVO4 nanosheets on graphene (u-BVG) toward the accelerated photocatalytic water oxidation reaction. Considering the Mott-Schottky heterojunctions at the contact interface in u-BVG, the feasible electron transfer from excited BiVO4 to graphene facilitates the holes to migrate onto the BiVO4 surface for the water oxidation reaction. Compared with the conventional synthesis strategies, our strategy avoids the introduction of Cl impurities. This modification allows for not only a ca. 0.1 eV deeper valence band edge position to generate holes with a stronger oxidation potential but the extraction of the impurity level to suppress the carrier recombination. And density functional theory calculations are in accordance with the above results. Impressively, these merits endow the u-BVG with ca. 16.8 times growth in the amount of ˙OH radicals derived from OH-/H2O oxidation, an over 260% enhancement in O2 yield and a 1.6-fold increase in the apparent quantum efficiency relative to the impure counterpart. This work paves the way for the reconstruction of graphene-based binary systems with high performance in solar-to-chemical energy conversion.
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Affiliation(s)
- Siyuan Liu
- State Key Laboratory of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China.
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23
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Yu W, Fu HJ, Mueller T, Brunschwig BS, Lewis NS. Atomic force microscopy: Emerging illuminated and operando techniques for solar fuel research. J Chem Phys 2020; 153:020902. [PMID: 32668946 DOI: 10.1063/5.0009858] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Integrated photoelectrochemical devices rely on the synergy between components to efficiently generate sustainable fuels from sunlight. The micro- and/or nanoscale characteristics of the components and their interfaces often control critical processes of the device, such as charge-carrier generation, electron and ion transport, surface potentials, and electrocatalysis. Understanding the spatial properties and structure-property relationships of these components can provide insight into designing scalable and efficient solar fuel components and systems. These processes can be probed ex situ or in situ with nanometer-scale spatial resolution using emerging scanning-probe techniques based on atomic force microscopy (AFM). In this Perspective, we summarize recent developments of AFM-based techniques relevant to solar fuel research. We review recent progress in AFM for (1) steady-state and dynamic light-induced surface photovoltage measurements; (2) nanoelectrical conductive measurements to resolve charge-carrier heterogeneity and junction energetics; (3) operando investigations of morphological changes, as well as surface electrochemical potentials, currents, and photovoltages in liquids. Opportunities for research include: (1) control of ambient conditions for performing AFM measurements; (2) in situ visualization of corrosion and morphological evolution of electrodes; (3) operando AFM techniques to allow nanoscale mapping of local catalytic activities and photo-induced currents and potentials.
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Affiliation(s)
- Weilai Yu
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, USA
| | - Harold J Fu
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, USA
| | - Thomas Mueller
- Bruker Nano Surfaces, 112 Robin Hill Road, Santa Barbara, California 93111, USA
| | - Bruce S Brunschwig
- Beckman Institute, California Institute of Technology, Pasadena, California 91125, USA
| | - Nathan S Lewis
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, USA
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24
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Zhang Z, Nagashima H, Tachikawa T. Ultra‐Narrow Depletion Layers in a Hematite Mesocrystal‐Based Photoanode for Boosting Multihole Water Oxidation. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202001919] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- Zhujun Zhang
- Department of Chemistry Graduate School of Science Kobe University 1-1 Rokkodai-cho Nada-ku Kobe 657-8501 Japan
| | - Hiroki Nagashima
- Molecular Photoscience Research Center Kobe University 1-1 Rokkodai-cho, Nada-ku Kobe 657-8501 Japan
- Present address: Department of Chemistry Graduate School of Science and Engineering Saitama University 255 Shimo-Okubo, Sakuraku Saitama 338-8570 Japan
| | - Takashi Tachikawa
- Molecular Photoscience Research Center Kobe University 1-1 Rokkodai-cho, Nada-ku Kobe 657-8501 Japan
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25
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Kim K, Yang J, Moon JH. Unveiling the Effects of Nanostructures and Core Materials on Charge-Transport Dynamics in Heterojunction Electrodes for Photoelectrochemical Water Splitting. ACS APPLIED MATERIALS & INTERFACES 2020; 12:21894-21902. [PMID: 32366085 DOI: 10.1021/acsami.0c03958] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Understanding the photogenerated charge-transport dynamics of metal oxide electrodes is the key to providing a strategy for practical improvement in the photoelectrochemical reaction activity. Here, we analyze the electron transport of a 3D bicontinuous SnO2/BiVO4 nanostructured photoelectrode by intensity-modulated photocurrent spectroscopy. We compare this electrode with 3D WO3/BiVO4 and planar-type bilayer SnO2/BiVO4 electrodes. In the results, we observe an order of magnitude faster electron transport in the 3D electrodes relative to the bilayer electrode. Moreover, we observe trap-limited transport on widely applied WO3/BiVO4 electrodes but confirm rapid trap-free transport on 3D SnO2/BiVO4. We also characterize the effect of electron transport on the water-splitting reaction. The electron-transport rate is directly related to the charge-separation efficiency in the water-splitting reaction. The fast transport time of the 3D SnO2/BiVO4 leads to the achievement of a significantly higher charge separation efficiency of 94%.
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Affiliation(s)
- Kiwon Kim
- Department of Chemical and Biomolecular Engineering, Sogang University, Baekbeom-ro 35, Mapo-gu, Seoul 04107, Republic of Korea
| | - Jiwoo Yang
- Department of Chemical and Biomolecular Engineering, Sogang University, Baekbeom-ro 35, Mapo-gu, Seoul 04107, Republic of Korea
| | - Jun Hyuk Moon
- Department of Chemical and Biomolecular Engineering, Sogang University, Baekbeom-ro 35, Mapo-gu, Seoul 04107, Republic of Korea
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26
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Zhang Z, Nagashima H, Tachikawa T. Ultra-Narrow Depletion Layers in a Hematite Mesocrystal-Based Photoanode for Boosting Multihole Water Oxidation. Angew Chem Int Ed Engl 2020; 59:9047-9054. [PMID: 32173995 DOI: 10.1002/anie.202001919] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2020] [Revised: 03/11/2020] [Indexed: 11/10/2022]
Abstract
Significant charge recombination that is difficult to suppress limits the practical applications of hematite (α-Fe2 O3 ) for photoelectrochemical water splitting. In this study, Ti-modified hematite mesocrystal superstructures assembled from highly oriented tiny nanoparticle (NP) subunits with sizes of ca. 5 nm were developed to achieve the highest photocurrent density (4.3 mA cm-2 at 1.23 V vs. RHE) ever reported for hematite-based photoanodes under back illumination. Owing to rich interfacial oxygen vacancies yielding an exceedingly high carrier density of 4.1×1021 cm-3 for super bulk conductivity in the electrode and a large proportion of ultra-narrow depletion layers (<1 nm) inside the mesoporous film for significantly improved hole collection efficiency, a boosting of multihole water oxidation with very low activation energy (Ea =44 meV) was realized.
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Affiliation(s)
- Zhujun Zhang
- Department of Chemistry, Graduate School of Science, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe, 657-8501, Japan
| | - Hiroki Nagashima
- Molecular Photoscience Research Center, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe, 657-8501, Japan.,Present address: Department of Chemistry, Graduate School of Science and Engineering, Saitama University, 255 Shimo-Okubo, Sakuraku, Saitama, 338-8570, Japan
| | - Takashi Tachikawa
- Molecular Photoscience Research Center, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe, 657-8501, Japan
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27
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Pan Q, Li A, Zhang Y, Yang Y, Cheng C. Rational Design of 3D Hierarchical Ternary SnO 2/TiO 2/BiVO 4 Arrays Photoanode toward Efficient Photoelectrochemical Performance. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2020; 7:1902235. [PMID: 32042560 PMCID: PMC7001624 DOI: 10.1002/advs.201902235] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Revised: 09/28/2019] [Indexed: 05/09/2023]
Abstract
BiVO4 as a promising semiconductor absorber is widely investigated as photoanode in photoelectrochemical water splitting. Herein, the rational design of 3D hierarchical ternary SnO2/TiO2/BiVO4 arrays is reported as photoanode for photoelectrochemical application, in which the SnO2 hierarchically hollow microspheres core/nanosheets shell arrays act as conductive skeletons, while the sandwiched TiO2 and surface BiVO4 are working as hole blocking layer and light absorber, respectively. Arising to the hierarchically ordered structure and synergistic effect between each component in the composite, the ternary SnO2/TiO2/BiVO4 photoanode enables high light harvesting efficiency as well as enhanced charge transport and separation efficiency, yielding a maximum photocurrent density of ≈5.03 mA cm-2 for sulfite oxidation and ≈3.1 mA cm-2 for water oxidation, respectively, measured at 1.23 V versus reversible hydrogen electrode under simulated air mass (AM) 1.5 solar light illumination. The results reveal that electrode design and interface engineering play important roles on the overall PEC performance.
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Affiliation(s)
- Qin Pan
- Shanghai Key Laboratory of Special Artificial Microstructure Materials and TechnologySchool of Physics Science and EngineeringTongji UniversityShanghai200092P. R. China
| | - Aoshuang Li
- Shanghai Key Laboratory of Special Artificial Microstructure Materials and TechnologySchool of Physics Science and EngineeringTongji UniversityShanghai200092P. R. China
| | - Yuanlu Zhang
- Shanghai Key Laboratory of Special Artificial Microstructure Materials and TechnologySchool of Physics Science and EngineeringTongji UniversityShanghai200092P. R. China
| | - Yaping Yang
- Shanghai Key Laboratory of Special Artificial Microstructure Materials and TechnologySchool of Physics Science and EngineeringTongji UniversityShanghai200092P. R. China
| | - Chuanwei Cheng
- Shanghai Key Laboratory of Special Artificial Microstructure Materials and TechnologySchool of Physics Science and EngineeringTongji UniversityShanghai200092P. R. China
- Institute of Dongguan‐Tongji UniversityDongguanGuangdong523808P. R. China
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28
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Laskowski FAL, Oener SZ, Nellist MR, Gordon AM, Bain DC, Fehrs JL, Boettcher SW. Nanoscale semiconductor/catalyst interfaces in photoelectrochemistry. NATURE MATERIALS 2020; 19:69-76. [PMID: 31591528 DOI: 10.1038/s41563-019-0488-z] [Citation(s) in RCA: 71] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Accepted: 08/18/2019] [Indexed: 05/12/2023]
Abstract
Semiconductor structures (for example, films, wires, particles) used in photoelectrochemical devices are often decorated with nanoparticles that catalyse fuel-forming reactions, including water oxidation, hydrogen evolution or carbon-dioxide reduction. For high performance, the catalyst nanoparticles must form charge-carrier-selective contacts with the underlying light-absorbing semiconductor, facilitating either hole or electron transfer while inhibiting collection of the opposite carrier. Despite the key role played by such selective contacts in photoelectrochemical energy conversion and storage, the underlying nanoscale interfaces are poorly understood because direct measurement of their properties is challenging, especially under operating conditions. Using an n-Si/Ni photoanode model system and potential-sensing atomic force microscopy, we measure interfacial electron-transfer processes and map the photovoltage generated during photoelectrochemical oxygen evolution at nanoscopic semiconductor/catalyst interfaces. We discover interfaces where the selectivity of low-Schottky-barrier n-Si/Ni contacts for holes is enhanced via a nanoscale size-dependent pinch-off effect produced when surrounding high-barrier regions develop during device operation. These results thus demonstrate (1) the ability to make nanoscale operando measurements of contact properties under practical photoelectrochemical conditions and (2) a design principle to control the flow of electrons and holes across semiconductor/catalyst junctions that is broadly relevant to different photoelectrochemical devices.
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Affiliation(s)
| | - Sebastian Z Oener
- Department of Chemistry and Biochemistry, University of Oregon, Eugene, OR, USA
| | - Michael R Nellist
- Department of Chemistry and Biochemistry, University of Oregon, Eugene, OR, USA
| | - Adrian M Gordon
- Department of Chemistry and Biochemistry, University of Oregon, Eugene, OR, USA
| | - David C Bain
- Department of Chemistry and Biochemistry, University of Oregon, Eugene, OR, USA
| | - Jessica L Fehrs
- Department of Chemistry and Biochemistry, University of Oregon, Eugene, OR, USA
| | - Shannon W Boettcher
- Department of Chemistry and Biochemistry, University of Oregon, Eugene, OR, USA.
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29
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Gao Y, Nie W, Wang X, Fan F, Li C. Advanced space- and time-resolved techniques for photocatalyst studies. Chem Commun (Camb) 2020; 56:1007-1021. [DOI: 10.1039/c9cc07128h] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Nanoparticle photocatalysts present the obvious characteristic of heterogeneity in structure, energy, and function at spatial and temporal scales.
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Affiliation(s)
- Yuying Gao
- State Key Laboratory of Catalysis
- Dalian National Laboratory for Clean Energy
- The Collaborative Innovation Centre of Chemistry for Energy Materials (iChEM)
- Dalian Institute of Chemical Physics
- Chinese Academy of Sciences
| | - Wei Nie
- State Key Laboratory of Catalysis
- Dalian National Laboratory for Clean Energy
- The Collaborative Innovation Centre of Chemistry for Energy Materials (iChEM)
- Dalian Institute of Chemical Physics
- Chinese Academy of Sciences
| | - Xiuli Wang
- State Key Laboratory of Catalysis
- Dalian National Laboratory for Clean Energy
- The Collaborative Innovation Centre of Chemistry for Energy Materials (iChEM)
- Dalian Institute of Chemical Physics
- Chinese Academy of Sciences
| | - Fengtao Fan
- State Key Laboratory of Catalysis
- Dalian National Laboratory for Clean Energy
- The Collaborative Innovation Centre of Chemistry for Energy Materials (iChEM)
- Dalian Institute of Chemical Physics
- Chinese Academy of Sciences
| | - Can Li
- State Key Laboratory of Catalysis
- Dalian National Laboratory for Clean Energy
- The Collaborative Innovation Centre of Chemistry for Energy Materials (iChEM)
- Dalian Institute of Chemical Physics
- Chinese Academy of Sciences
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30
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Selim S, Pastor E, García-Tecedor M, Morris MR, Francàs L, Sachs M, Moss B, Corby S, Mesa CA, Gimenez S, Kafizas A, Bakulin AA, Durrant JR. Impact of Oxygen Vacancy Occupancy on Charge Carrier Dynamics in BiVO4 Photoanodes. J Am Chem Soc 2019; 141:18791-18798. [DOI: 10.1021/jacs.9b09056] [Citation(s) in RCA: 104] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Shababa Selim
- Department of Chemistry and Centre for Plastic Electronics, MSRH, White City Campus, Imperial College London, London W12 0BZ, United Kingdom
| | - Ernest Pastor
- Department of Chemistry and Centre for Plastic Electronics, MSRH, White City Campus, Imperial College London, London W12 0BZ, United Kingdom
| | | | - Madeleine R. Morris
- Department of Chemistry and Centre for Plastic Electronics, MSRH, White City Campus, Imperial College London, London W12 0BZ, United Kingdom
| | - Laia Francàs
- Department of Chemistry and Centre for Plastic Electronics, MSRH, White City Campus, Imperial College London, London W12 0BZ, United Kingdom
| | - Michael Sachs
- Department of Chemistry and Centre for Plastic Electronics, MSRH, White City Campus, Imperial College London, London W12 0BZ, United Kingdom
| | - Benjamin Moss
- Department of Chemistry and Centre for Plastic Electronics, MSRH, White City Campus, Imperial College London, London W12 0BZ, United Kingdom
| | - Sacha Corby
- Department of Chemistry and Centre for Plastic Electronics, MSRH, White City Campus, Imperial College London, London W12 0BZ, United Kingdom
| | - Camilo A. Mesa
- Department of Chemistry and Centre for Plastic Electronics, MSRH, White City Campus, Imperial College London, London W12 0BZ, United Kingdom
| | - Sixto Gimenez
- Institute of Advanced Materials (INAM), Universitat Jaume I, 12006 Castelló, Spain
| | - Andreas Kafizas
- Department of Chemistry and Centre for Plastic Electronics, MSRH, White City Campus, Imperial College London, London W12 0BZ, United Kingdom
- The Grantham Institute, Imperial College London, South Kensington, London SW7 2AZ, United Kingdom
| | - Artem A. Bakulin
- Department of Chemistry and Centre for Plastic Electronics, MSRH, White City Campus, Imperial College London, London W12 0BZ, United Kingdom
| | - James R. Durrant
- Department of Chemistry and Centre for Plastic Electronics, MSRH, White City Campus, Imperial College London, London W12 0BZ, United Kingdom
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31
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Wang Z, Huang X, Wang X. Recent progresses in the design of BiVO4-based photocatalysts for efficient solar water splitting. Catal Today 2019. [DOI: 10.1016/j.cattod.2019.01.067] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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32
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Pan Q, Zhang H, Yang Y, Cheng C. 3D Brochosomes-Like TiO 2 /WO 3 /BiVO 4 Arrays as Photoanode for Photoelectrochemical Hydrogen Production. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2019; 15:e1900924. [PMID: 31165562 DOI: 10.1002/smll.201900924] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Revised: 05/09/2019] [Indexed: 06/09/2023]
Abstract
An ideal photoelectrochemical (PEC) anode should process effective light absorption, charge transport, and separation efficiency. Here, a novel 3D brochosomes-like TiO2 /WO3 /BiVO4 array as an efficient photoanode by combining a colloid polystyrene sphere template and electrochemical deposition routes for PEC hydrogen generation is reported. The as-fabricated 3D TiO2 /WO3 /BiVO4 brochosomes photoanode yields excellent PEC performance with photocurrent densities of ≈3.13 and ≈4.27 mA cm-2 with FeOOH/NiOOH catalyst, respectively, measured in 0.5 m Na2 SO4 solution with 0.1 m Na2 SO3 at 1.23 V versus reversible hydrogen electrode (RHE) under simulated AM1.5 light illumination, which is ≈6 times the reference sample of a planar WO3 /BiVO4 film electrode. The significantly improved performance could be benefited from the ordered hollow porous structure that provides enhanced light absorption and efficient charge transport as well as improved charge separation efficiency by WO3 /BiVO4 "host-guest" heterojunctions.
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Affiliation(s)
- Qin Pan
- Shanghai Key Laboratory of Special Artificial Microstructure Materials and Technology, School of Physics Science and Engineering, Tongji University, Shanghai, 200092, P. R. China
| | - Haifeng Zhang
- School of Materials and Energy, Guangdong University of Technology, Guangzhou, 510006, P. R. China
| | - Yaping Yang
- Shanghai Key Laboratory of Special Artificial Microstructure Materials and Technology, School of Physics Science and Engineering, Tongji University, Shanghai, 200092, P. R. China
| | - Chuanwei Cheng
- Shanghai Key Laboratory of Special Artificial Microstructure Materials and Technology, School of Physics Science and Engineering, Tongji University, Shanghai, 200092, P. R. China
- Institute of Dongguan-Tongji University, Dongguan, Guangdong, 523808, P. R. China
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33
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Kim JH, Lee JS. Elaborately Modified BiVO 4 Photoanodes for Solar Water Splitting. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2019; 31:e1806938. [PMID: 30793384 DOI: 10.1002/adma.201806938] [Citation(s) in RCA: 175] [Impact Index Per Article: 35.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2018] [Revised: 12/24/2018] [Indexed: 05/17/2023]
Abstract
Photoelectrochemical (PEC) cells for solar-energy conversion have received immense interest as a promising technology for renewable hydrogen production. Their similarity to natural photosynthesis, utilizing sunlight and water, has provoked intense research for over half a century. Among many potential photocatalysts, BiVO4 , with a bandgap of 2.4-2.5 eV, has emerged as a highly promising photoanode material with a good chemical stability, environmental inertness, and low cost. Unfortunately, its charge transport properties are modest, at most a hole diffusion length (Lp ) of ≈70 nm. However, recent rapid developments in multiple modification strategies have elevated it to a position as the most promising metal oxide photoanode material. This review summarizes developments in BiVO4 photoanodes in the past 10 years, in which time it has continuously broken its own performance records for PEC water oxidation. Effective modification techniques are discussed, including synthesis of nanostructures/nanopores, external/internal doping, heterojunction fabrication, surface passivation, and cocatalysts. Tandem systems for unassisted solar water splitting and PEC production of value-added chemicals are also discussed.
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Affiliation(s)
- Jin Hyun Kim
- Department of Energy Engineering, School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea
| | - Jae Sung Lee
- Department of Energy Engineering, School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea
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34
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Lee H, Lee H, Park JY. Direct Imaging of Surface Plasmon-Driven Hot Electron Flux on the Au Nanoprism/TiO 2. NANO LETTERS 2019; 19:891-896. [PMID: 30608712 DOI: 10.1021/acs.nanolett.8b04119] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Direct measurement of hot electron flux from a plasmonic Schottky nanodiode is important for obtaining fundamental insights explaining the mechanism for electronic excitation on a surface. Here, we report the measurement of photoinduced hot electrons on a triangular Au nanoprism on TiO2 under incident light with photoconductive atomic force microscopy (pc-AFM), which is direct proof of the intrinsic relation between hot electrons and localized surface plasmon resonance. We find that the local photocurrent measured on the boundary of the Au nanoprism is higher than that inside the Au nanoprism, indicating that field confinement at the boundary of the Au nanoprism acts as a hot spot, leading to the enhancement of hot electron flow at the boundary. Under incident illumination with a wavelength near the absorption peak (645 nm) of a single Au nanoprism, localized surface plasmon resonance resulted in the generation of a higher photoinduced hot electron flow for the Au nanoprism/TiO2, compared with that at a wavelength of 532 nm. We show that the application of a reverse bias results in a higher photocurrent for the Au nanoprism/TiO2, which is associated with a lowering of the Schottky barrier height caused by the image force. These nanoscale measurements of hot electron flux with pc-AFM indicate efficient photon energy transfer mediated by surface plasmons in hot electron-based energy conversion.
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Affiliation(s)
- Hyunhwa Lee
- Graduate School of EEWS and Department of Chemistry , Korea Advanced Institute of Science and Technology (KAIST) , Daejeon 34141 , Republic of Korea
- Center for Nanomaterials and Chemical Reactions , Institute for Basic Science (IBS) , Daejeon 34141 , Republic of Korea
| | - Hyunsoo Lee
- Center for Nanomaterials and Chemical Reactions , Institute for Basic Science (IBS) , Daejeon 34141 , Republic of Korea
| | - Jeong Young Park
- Graduate School of EEWS and Department of Chemistry , Korea Advanced Institute of Science and Technology (KAIST) , Daejeon 34141 , Republic of Korea
- Center for Nanomaterials and Chemical Reactions , Institute for Basic Science (IBS) , Daejeon 34141 , Republic of Korea
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35
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Laskowski FAL, Nellist MR, Qiu J, Boettcher SW. Metal Oxide/(oxy)hydroxide Overlayers as Hole Collectors and Oxygen-Evolution Catalysts on Water-Splitting Photoanodes. J Am Chem Soc 2018; 141:1394-1405. [PMID: 30537811 DOI: 10.1021/jacs.8b09449] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Solar water splitting provides a mechanism to convert and store solar energy in the form of stable chemical bonds. Water-splitting systems often include semiconductor photoanodes, such as n-Fe2O3 and n-BiVO4, which use photogenerated holes to oxidize water. These photoanodes often exhibit improved performance when coated with metal-oxide/(oxy)hydroxide overlayers that are catalytic for the water-oxidation reaction. The mechanism for this improvement, however, remains a controversial topic. This is, in part, due to a lack of experimental techniques that are able to directly track the flow of photogenerated holes in such multicomponent systems. In this Perspective, we illustrate how this issue can be addressed by using a second working electrode to make direct current/voltage measurements on the catalytic overlayer during operation in a photoelectrochemical cell. We discuss examples where the second working electrode is a thin metallic film deposited on the catalyst layer, as well as where it is the tip of a conducting atomic-force-microscopy probe. In applying these techniques to multiple semiconductors (Fe2O3, BiVO4, Si) paired with various metal-(oxy)hydroxide overlayers (e.g., Ni(Fe)O xH y and CoO xH y), we found in all cases investigated that the overlayers collect photogenerated holes from the semiconductor, charging to potentials sufficient to drive water oxidation. The overlayers studied thus form charge-separating heterojunctions with the semiconductor as well as serve as water-oxidation catalysts.
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Affiliation(s)
- Forrest A L Laskowski
- Department of Chemistry and Biochemistry , University of Oregon , Eugene , Oregon 97403 , United States
| | - Michael R Nellist
- Department of Chemistry and Biochemistry , University of Oregon , Eugene , Oregon 97403 , United States
| | - Jingjing Qiu
- Department of Chemistry and Biochemistry , University of Oregon , Eugene , Oregon 97403 , United States
| | - Shannon W Boettcher
- Department of Chemistry and Biochemistry , University of Oregon , Eugene , Oregon 97403 , United States
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36
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Liao A, Chen R, Fan F, Xiao L, He H, Zhang C, Asiri AM, Zhou Y, Li C, Zou Z. Integration of Fe xS electrocatalysts and simultaneously generated interfacial oxygen vacancies to synergistically boost photoelectrochemical water splitting of Fe 2O 3 photoanodes. Chem Commun (Camb) 2018; 54:13817-13820. [PMID: 30460938 DOI: 10.1039/c8cc08350a] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Integration of FexS electrocatalysts and simultaneously generated interfacial oxygen vacancies (VO) was designed to promote the water splitting performance of Fe2O3 photoanodes, in which a synergistic effect remarkably reduces the carrier recombination, increases the number of active sites, and facilitates the photogenerated holes to participate in water oxidation.
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Affiliation(s)
- Aizhen Liao
- National Laboratory of Solid State Microstructures, Collaborative Innovation Center of Advanced Microstructures, School of Physics, Nanjing University, Nanjing 210093, P. R. China.
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37
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Eichhorn J, Kastl C, Schwartzberg AM, Sharp ID, Toma FM. Disentangling the Role of Surface Chemical Interactions on Interfacial Charge Transport at BiVO 4 Photoanodes. ACS APPLIED MATERIALS & INTERFACES 2018; 10:35129-35136. [PMID: 30230810 DOI: 10.1021/acsami.8b11366] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Chemical transformations that occur on photoactive materials, such as photoelectrochemical water splitting, are strongly influenced by the surface properties as well as by the surrounding environment. Herein, we elucidate the effects of oxygen and water surface adsorption on band alignment, interfacial charge transfer, and charge-carrier transport by using complementary Kelvin probe measurements and photoconductive atomic force microscopy on bismuth vanadate. By observing variations in surface potential, we show that adsorbed oxygen acts as an electron-trap state at the surface of bismuth vanadate, whereas adsorbed water results in formation of a dipole layer without inducing interfacial charge transfer. The apparent change of trap state density under dry or humid nitrogen, as well as under oxygen-rich atmosphere, proves that surface adsorbates influence charge-carrier transport properties in the material. The finding that oxygen introduces electronically active states on the surface of bismuth vanadate may have important implications for understanding functional characteristics of water splitting photoanodes, devising strategies to passivate interfacial trap states, and elucidating important couplings between energetics and charge transport in reaction environments.
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Affiliation(s)
| | | | | | - Ian D Sharp
- Walter Schottky Institut and Physik Department , Technische Universität München , Am Coulombwall 4 , Garching 85748 , Germany
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