Investigation of the Optical and Excitonic Properties of the Visible Light-Driven Photocatalytic BiVO4 Material

An investigation of the optical and excitonic properties of photocatalytic compounds based on both experimental and theoretical approaches is proposed. More specifically, this paper reports, for the first time, the local-field, optical anisotropy, and excitonic effects in BiVO4, an active photocatalytic material in the visible range. The analyses are based on electron energy-loss spectroscopy measurements, ground-state density functional theory calculations, including crystal local-field effects, and many-body corrections using the Bethe-Salpeter equation. These results are supported by a comparison with two materials, namely, TiO2 anatase and rutile, which are well-known to differ in their photocatalytic properties, those being important and negligible, respectively. The analogies found for these two categories of compounds allow the proposal of criteria that appear to be essential for producing an optimal photocatalytic material.