Anisotropic electron transport limits performance of Bi2WO6 photoanodes
File(s)Bi2WO6 paper-revised2.docx (1.56 MB) Bi2WO6 paper_SI-Revised2.docx (1010.14 KB)
Accepted version
Supporting information
Author(s)
Type
Journal Article
Abstract
Bi2WO6 is one of the simplest members of the versatile Aurivillius oxide family of materials. As an intriguing model system for Aurivillius oxides, BiVO4 exhibits low water oxidation onset potentials (∼0.5–0.6 VRHE) for driven solar water oxidation. Despite this, Bi2WO6 also produces low photocurrents in comparison to other metal oxides. Due to a lack of in situ studies, the reasons for such poor performance are not understood. In this study, Bi2WO6 photoanodes are synthesized by aerosol-assisted chemical vapor deposition. The charge carrier dynamics of Bi2WO6 are studied in situ under water oxidation conditions, and the rate of both bulk recombination and water oxidation is found to be comparable to other metal oxide photoanodes. However, the rate of electron extraction is at least 10 times slower than the slowest kinetics previously reported in an oxide photoanode. First-principles analysis indicates that the slow electron extraction kinetics are linked to a strong anisotropy in the conduction band. Preferred or epitaxial growth along the conductive axes is a strategy to overcome slow electron transport and low photocurrent densities in layered materials such as Bi2WO6.
Date Issued
2020-09-03
Date Acceptance
2020-08-01
Citation
The Journal of Physical Chemistry C, 2020, 124 (35), pp.18859-18867
ISSN
1932-7447
Publisher
American Chemical Society (ACS)
Start Page
18859
End Page
18867
Journal / Book Title
The Journal of Physical Chemistry C
Volume
124
Issue
35
Copyright Statement
© 2020 American Chemical Society. This document is the Accepted Manuscript version of a Published Work that appeared in final form in Journal of Physical Chemistry C, after peer review and technical editing by the publisher. To access the final edited and published work see https://v2.sherpa.ac.uk/id/publication/7799
Sponsor
The Royal Society
Identifier
https://pubs.acs.org/doi/10.1021/acs.jpcc.0c03539
Grant Number
RSG\R1\180434
Subjects
Physical Chemistry
03 Chemical Sciences
09 Engineering
10 Technology
Publication Status
Published
Date Publish Online
2020-08-05