Suitable Fundamental Properties of Ta_0.75V_0.25ON Material for Visible-Light-Driven Photocatalysis: A DFT Study

By applying calculations based on density functional theory, and on density functional perturbation theory, together with generalized gradient approximation-Perdew-Burke-Emzerho and screened Coulomb hybrid HSE06 functionals, we predict novel and suitable fundamental parameters of the stable monoclinic Ta_0.75V_0.25ON semiconductor for solar water splitting. In addition to its predicted bandgap of 2.0 eV in the required zone for solar-driven water splitting, this material reveals a high visible-light absorption coefficient, high static dielectric constant, high hole and electron mobilities along the [001] and [010] crystallographic directions, relatively low exciton binding energy, and suitable band edge energy levels for oxidizing water and reducing protons. The optical, charge-carrier transport, and redox features predicted for this material are found to be considerably better than those obtained for Ta₃N₅, which is the most common semiconductor photocatalyst used in visible-light-driven water splitting.