Hole mediated coupling in Sr2Nb2O7 for visible light photocatalysis

Abstract

The band gap reduction and effective utilization of visible solar light are possible by introducing the anionic hole–hole mediated coupling in Sr₂Nb₂O₇. By using the first principles calculations, we have investigated the mono- and co-anionic doping (S, N and C) in layered perovskite Sr₂Nb₂O₇ for the visible-light photocatalysis. Our electronic structure and optical absorption study shows that the mono- (N and S) and co-anionic doped (N–N and C–S) Sr₂Nb₂O₇ systems are promising materials for the visible light photocatalysis. The calculated binding energies show that if the hole–hole mediated coupling could be introduced, the co-doped systems would be more stable than their respective mono-doped systems. Optical absorption curves indicate that doping S, (N–N) and (C–S) in Sr₂Nb₂O₇ can harvest a longer wavelength of the visible light spectrum as compared to the pure Sr₂Nb₂O₇ for efficient photocatalysis.