Photocorrosion of WO3 Photoanodes in Different Electrolytes

Knöppel J, Kormanyos A, Mayerhöfer B, Hofer A, Bierling M, Bachmann J, Thiele S, Cherevko S (2021)

Publication Language: English

Publication Type: Journal article, Original article

Publication year: 2021


Original Authors: Julius Knöppel, Attila Kormányos, Britta Mayerhöfer, André Hofer, Markus Bierling, Julien Bachmann, Simon Thiele, Serhiy Cherevko

Book Volume: 1

Pages Range: 6-13

Article Number: acsphyschemau.1c00004

Journal Issue: 1

DOI: 10.1021/acsphyschemau.1c00004


Photocorrosion of an n-type semiconductor is anticipated to be unfavorable if its decomposition potential is situated below its valence band-edge position. Tungsten trioxide (WO3) is generally considered as a stable photoanode for different photoelectrochemical (PEC) applications. Such oversimplified considerations ignore reactions with electrolytes added to the solvent. Moreover, kinetic effects are neglected. The fallacy of such approaches has been demonstrated in our previous study dealing with WO3 instability in H2SO4. In this work, in order to understand parameters influencing WO3 photocorrosion and to identify more suitable reaction environments, H2SO4, HClO4, HNO3, CH3O3SH, as electrolytes are considered. Model WO3 thin films are fabricated with a spray-coating process. Photoactivity of the samples is determined with a photoelectrochemical scanning flow cell. Photostability is measured in real time by coupling an inductively coupled plasma mass spectrometer to the scanning flow cell to determine the photoanode dissolution products. It is found that the photoactivity of the WO3 films increases as HNO3 < HClO4 ≈ H2SO4 < CH3O3SH, whereas the photostability exhibits the opposite trend. The differences observed in photocorrosion are explained considering stability of the electrolytes toward decomposition. This work demonstrates that electrolytes and their reactive intermediates clearly influence the photostability of photoelectrodes. Thus, the careful selection of the photoelectrode/electrolyte combination is of crucial importance in the design of a stable photoelectrochemical water-splitting device.

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Knöppel, J., Kormanyos, A., Mayerhöfer, B., Hofer, A., Bierling, M., Bachmann, J.,... Cherevko, S. (2021). Photocorrosion of WO3 Photoanodes in Different Electrolytes. ACS Physical Chemistry Au, 1(1), 6-13.


Knöppel, Julius, et al. "Photocorrosion of WO3 Photoanodes in Different Electrolytes." ACS Physical Chemistry Au 1.1 (2021): 6-13.

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