Effects of Structural Variation on the Photocatalytic Performance of Hydrothermally Synthesized BiVO₄

Abstract

Abstract Highly crystalline monoclinic scheelite BiVO 4 powders are synthesized from aqueous Bi(NO 3 ) 3 and NH 4 VO 3 solutions over a wide range of pH by a hydrothermal process. BiVO 4 powders with various morphologies, surface textures, and grain shapes are selectively synthesized by adjusting the pH. The dependence of the Raman peak position and intensity on the synthesis conditions indicates that the symmetry distortions in the local structure of the synthesized BiVO 4 are affected by the preparation conditions. These variations in the local structure result in the modification of the electronic structure of BiVO 4 , which results in a blue‐shift in the UV‐vis absorption spectrum of hydrothermally synthesized BiVO 4 in comparison with a well‐crystallized sample prepared by homogeneous coprecipitation. The photocatalytic activities for O 2 evolution from an aqueous AgNO 3 solution under visible‐light irradiation are strongly dependent on the pH used in the synthesis. The differences in the photocatalytic activities between BiVO 4 samples prepared under various conditions is attributed to the degree of structural distortion, leading to differences in the mobility of photogenerated holes formed in the valence band, which consists of Bi 6s and O 2p orbitals.