Electronic properties of highly-active AgAsO photocatalyst and its band gap modulation: An insight from hybrid-density functional calculations

The electronic structures of highly active Ag-based oxide photocatalysts AgAsO and AgPO are studied by hybrid-density functional calculations. It is revealed that AgAsO and AgPO are indirect band gap semiconductors. The Hartree-Fock mixing parameters are fitted for experimental band gaps of AgAsO (1.88 eV) and AgPO (2.43 eV). The smaller electron effective mass and the lower valence band edge of AgAsO are likely to be responsible for the superior photocatalytic oxidation reaction to AgPO. The comparable lattice constant and analogous crystal structure between the two materials allow the opportunities of fine-tuning the band gap of AgAsPO using a solid-solution approach. The development of AgAsPO should be promising for the discovery of novel visible-light sensitized photocatalysts.