Revealing Surface Charge Population on Flake-Like BiVO₄ Photocatalysts by Single Particle Imaging Spectroscopies

Visually observing the charge separation between different facets is of great importance for the development of high-efficiency photocatalysts. In this work, the techniques for visual observation and material strategy for catalyst synthesis were integrated to reveal the structure–activity relationship of a single BiVO 4 photocatalyst. BiVO 4 crystals with different ratios of (010)/(110) facets were synthesized by a pressure-assisted hydrothermal method. Spatially resolved surface photovoltage (SPV) indicated that photoinduced holes were prone to transfer from (010) facets to (110) facets on BiVO 4 . Both confocal fluorescence and Kelvin probe force microscopy (KPFM) evidenced the enhanced separation of photogenerated charge carriers by increasing the ratio of exposed (010) facets in flake-BiVO 4 . Profitting from the strategy of facet engineering, flake-BiVO 4 presented remarkably increased activity for photocatalytic O 2 production than that of truncated bipyramid-BiVO 4 . Our study provides a fundamental insight into the facet-dependent activity of BiVO 4 single particle, which is beneficial for the rational design of faceted photocatalyst for environmental remediation and solar energy conversion.