The nature of electron lone pairs in BiVO4

The electronic structure of BiVO4 has been studied by x-ray photoelectron, x-ray absorption, and x-ray emission spectroscopies, in comparison with density functional theory calculations. Our results confirm both the direct band gap of 2.48 eV and that the Bi 6s electrons hybridize with O 2p to form antibonding “lone pair” states at the top of the valence band. The results highlight the suitability of combining s2 and d0 cations to produce photoactive ternary oxides.