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SCIENCE CHINA Materials, Volume 61, Issue 6: 806-821(2018) https://doi.org/10.1007/s40843-018-9240-y

Photoelectrode for water splitting: Materials, fabrication and characterization

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  • ReceivedJan 31, 2018
  • AcceptedMar 5, 2018
  • PublishedApr 11, 2018

Abstract

Photoelectorchemical (PEC) water splitting is an attractive approach for producing sustainable and environment-friendly hydrogen. An efficient PEC process is rooted in appropriate semiconductor materials, which should possess small bandgap to ensure wide light harvest, facile charge separation to allow the generated photocharges migrating to the reactive sites and highly catalytic capability to fully utilize the separated photocharges. Proper electrode fabrication method is of equal importance for promoting charge transfer and accelerating surface reactions in the electrodes. Moreover, powerful characterization method can shed light on the complex PEC process and provide deep understanding of the rate-determining step for us to improve the PEC systems further. Targeting on high solar conversion efficiency, here we provide a review on the development of PEC water splitting in the aspect of materials exploring, fabrication method and characterization. It is expected to provide some fundamental insight of PEC and inspire the design of more effective PEC systems.


Funded by

the Australian Research Council through its Discovery Project(DP)

Federation Fellowship(FF)


Acknowledgment

This work is supported by the Australian Research Council through its Discovery Project (DP) and Federation Fellowship (FF) Program. The Queensland node of the Australian National Fabrication Facility (ANFF) is also appreciated.


Interest statement

The authors declare no conflict of interest.


Contributions statement

Wang L initiated and guided the whole work. Wang Z surveyed the literature, wrote the manuscript and discussed with Wang L.


Author information

Zhiliang Wang received his PhD degree (supervised by Prof. Can Li) in physical chemistry from Dalian Institute of Chemical Physics (DICP), Chinese Academy of Sciences in 2017 and now he works in Prof. Wang’s group as a post-doctoral fellow at The University of Queensland (UQ), Australia. His current research focuses on photoelectrochemical solar energy conversion.


Lianzhou Wang is a professor at the School of Chemical Engineering and the director of Nanomaterials Center, UQ, Australia. He received his PhD degree from the Chinese Academy of Sciences in 1999. Before joining UQ in 2004, he worked at two National Institutes (NIMS and AIST) of Japan for five years. Wang’s research interests mainly focus on the design and application of semiconducting nanomaterials in renewable energy conversion/storage systems, including photocatalysis, solar cell, rechargable batteries and so on.


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  • Figure 1

    The band structure of selected semiconductors, CZTS: CuZnSnS4.

  • Figure 2

    The schematic illustration of the PEC processes and the related influence factor of each step.

  • Figure 3

    (a) The schematic illustration of Ag decorated Fe2O3 nanoflakes with CoPi as cocatalyst. (b) The photocurrent of different Fe2O3 electrode measured under 100 W cm−2 simulated sunlight (AM 1.5G). Reprinted with permission from Ref. [41]. Copyright 2016, John Wiley & Sons, Inc.

  • Figure 4

    The band structure change when N 2p replaces O 2p orbital step by step. Reprinted with permission from Ref. [49]. Copyright 2003, American Chemical Society.

  • Figure 5

    (a) The schematic illustration of Ta3N5/TiO2/ferrihydrate/molecular catalyst photoelectrode. (b) The photocurrent of different Ta3N5 photoelectrode measured under 100 mW cm−2 simulated sunlight (AM 1.5G). Reprinted with permission from Ref. [50]. Copyright 2016, the Royal Society of Chemistry.

  • Figure 6

    The schematic illustration of PEDOT:PSS modified Si photoelectrode and the corresponding Tafel plot for HI splitting. Reprinted with permission from Ref. [62]. Copyright 2016, American Chemical Society.

  • Figure 7

    (a) The comparison of photocurrent of BiVO4 photoanode with different proportion of (040) facet exposure and the corresponding electrochemical treated electrodes. Reprinted with permission from Ref. [35]. Copyright 2017, John Wiley & Sons, Inc. (b) The morphology of porous BiVO4 electrode derived from BiOI nanoplate electrode. Reprinted with permission from Ref. [67]. Copyright 2014, the American Association for the Advancement of Science.

  • Figure 8

    (a) The schematic illustration of particle transfer method. (b) The performance of LaTiO2N photoelectrode with different contact layer. Reprinted with permission from Ref. [75]. Copyright 2013, the Royal Society of Chemistry.

  • Figure 9

    (a) The ZnO arrays prepared by CVD with gold as calalyst. Reprinted with permission from Ref. [79]. Copyright 2004, American Chemical Society. (b) The schematic illustration of different particle morphology deposited on films by PLD. Reprinted with permission from Ref. [80]. Copyright 2017, American Chemical Society.

  • Figure 10

    (a) The schematic illustration of equipment used for flame annealing electrode fabrication. (b) The MoO3 nanobelts prepared by flame annealing method. Reprinted with permission from Ref. [92]. Copyright 2011, the American Chemical Society.

  • Figure 11

    (a) The schematic illustration of in-situ X-ray absorption characterization of hematite electrode. (b) The O 1s EXAFS changes along with different applied bias under illumination. Reprinted with permission from Ref. [95]. Copyright 2012, the American Chemcial Society.

  • Figure 12

    (a) The decay of hole absorption peaked at 580 nm as illustrated in the inserted pattern. Reprinted with permission from Ref. [98]. Copyright 2013, the Royal Society of Chemistry. (b) The reaction order change along with the surface hole density. Reprinted with permission from Ref. [99]. Copyright 2015, the American Chemical Society.

  • Figure 13

    (a) The steady-state PL of Ta3N5 photoelectrode calcined at different temperature. Reprinted with permission from Ref. [103]. Copyright 2015, the American Chemical Society. (b) The TPL of perovskite film with different hole transfer layer to quench the PL. Reprinted with permission from Ref. [105]. Copyright 2017, the American Association for the Advancement of Science.

  • Figure 14

    (a) The full equivalent circuit for interpretation of the Fe2O3/CoPi system. Reprinted with permission from Ref. [106]. Copyright 2012, the American Chemical Society. (b) A calculated IMPS response when krec=10ktr. Reprinted with permission from Ref. [108]. Copyright 2013, Springer.

  • Figure 15

    (a) The energy diagram to show the energy level alignment of a dual working electrode system. Reprinted with permission from Ref. [111]. Copyright 2018, Macmillan Publishers Limited. (b) The schematic show of the dual working electrode. Reprinted with permission from Ref. [112]. Copyright 2014, Macmillan Publishers Limited.

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