Nanometer-Resolved Operando Photo-Response of Faceted BiVO4 Semiconductor Nanoparticles

Shaoqiang Su, Igor Siretanu, Dirk van den Ende, Bastian Mei, Guido Mul, Frieder Mugele*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

1 Citation (Scopus)
7 Downloads (Pure)

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.

Original languageEnglish
Pages (from-to)2248–2256
Number of pages9
JournalJournal of the American Chemical Society
Volume146
Issue number3
Early online date12 Jan 2024
DOIs
Publication statusPublished - 24 Jan 2024

Keywords

  • UT-Hybrid-D

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