Significance of Crystal Morphology Controlling in Semiconductor-Based Photocatalysis: A Case Study on BiVO₄ Photocatalyst

Abstract

Precise control of the morphology and crystalline structure of semiconductor-based photocatalyst is crucial for improving the efficiency of solar energy conversion system. In this work, taking BiVO 4 semiconductor photocatalyst as an example, we investigated the formation process for the regular decahedron BiVO 4 crystals prepared by a convenient hydrothermal method and found that the synthesis is undergoing a dissolution–recrystallization process, concomitantly, the phase was transformed from tetragonal zircon type to monoclinic sheelite-type. By controlling the kinetics of crystal growth for BiVO 4 through regulating acidity of the reaction solution, we rationally tune the morphology of monoclinic BiVO 4 from regular decahedron crystals to short rod-like particles, particularly precisely modulate the proportion of {010}/{011} facets for the decahedron BiVO 4 . By tuning the crystalline phase and morphologies of BiVO 4 crystal, we found that the photocatalytic water oxidation activity for the well-defined BiVO 4 crystal with specific configuration of {010} and {011} exposed facets can be 50 times of tetragonal BiVO 4 particles. Our work shows a convenient strategy for precise control of the growth process of semiconductor-based photocatalyst, based on the understanding of the crystal morphology evolution mechanism, which will be instructive for constructing semiconductor-based photocatalysts for solar energy conversion.