Ab Initio Calculation of Surface-Controlled Photocatalysis in Multiple-Phase BiVO₄

Bismuth vanadate (BiVO₄) is one of the semiconductors that are often used for photoelectrochemical water splitting, because of its low band gap and various crystalline phases. Using density functional theory (DFT) based calculations, the surface properties, electronic structures, and photocatalytic properties of different facets are obtained. These include the (001), (011), and (101) facets that are truncated from ms-BiVO₄ and the comparable {001}, {011}, and {101} facets that are produced by means of cleavage from ts-BiVO₄. Our findings show a surface stability order of (001)/{001} > (101)/{101} > (011)/{011}. The (011) and {011} facets present distinct surface properties owing to the asymmetric a-–b plane of ms- BiVO₄, in contrast to ts-BiVO₄. The work function of the {011} facet is dramatically decreased by 1 eV in comparison to the other facets, resulting from a positive surface dipole with an open lattice. Surface (001) shares geometric and electronic structures characteristics with {001}, and surface (101) possesses identical features with {101}. Furthermore, we confirm that the discrepancies between the (011) and {011} surfaces in facet morphologies and electronic structures are one of the reasons accounting for the distinct photoelectrochemical activities of ms- and ts-BiVO₄ from experiments.