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Title: Mechanistic insights into chemical and photochemical transformations of bismuth vanadate photoanodes

Artificial photosynthesis relies on the availability of semiconductors that are chemically stable and can efficiently capture solar energy. Although metal oxide semiconductors have been investigated for their promise to resist oxidative attack, materials in this class can suffer from chemical and photochemical instability. Here we present a methodology for evaluating corrosion mechanisms and apply it to bismuth vanadate, a state-of-the-art photoanode. Analysis of changing morphology and composition under solar water splitting conditions reveals chemical instabilities that are not predicted from thermodynamic considerations of stable solid oxide phases, as represented by the Pourbaix diagram for the system. Computational modelling indicates that photoexcited charge carriers accumulated at the surface destabilize the lattice, and that self-passivation by formation of a chemically stable surface phase is kinetically hindered. Although chemical stability of metal oxides cannot be assumed, insight into corrosion mechanisms aids development of protection strategies and discovery of semiconductors with improved stability.
Authors:
 [1] ;  [2] ;  [3] ;  [4] ;  [2] ;  [2] ;  [5] ;  [2] ;  [6] ;  [7] ;  [6] ;  [6] ;  [4] ;  [4] ;  [2] ;  [8] ;  [2]
  1. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Joint Center for Artificial Photosynthesis, Chemical Sciences Division
  2. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Joint Center for Artificial Photosynthesis, Chemical Sciences Division
  3. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Joint Center for Artificial Photosynthesis; Technical Univ. of Munich (Germany). Walter Schottky Inst. and Physics Dept.
  4. California Inst. of Technology (CalTech), Pasadena, CA (United States). Joint Center for Artificial Photosynthesis, Division of Chemistry and Chemical Engineering
  5. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Molecular Foundry, Materials Sciences Division
  6. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Joint Center for Artificial Photosynthesis, Materials Sciences Division
  7. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Materials Sciences Division
  8. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Joint Center for Artificial Photosynthesis, Energy Technologies Area; Univ. of California, Berkeley, CA (United States). Materials Science and Engineering
Publication Date:
Grant/Contract Number:
AC02-05CH11231; SC0004993
Type:
Accepted Manuscript
Journal Name:
Nature Communications
Additional Journal Information:
Journal Volume: 7; Journal ID: ISSN 2041-1723
Publisher:
Nature Publishing Group
Research Org:
Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; photocatalysis; photochemistry; physical chemistry
OSTI Identifier:
1379503