Hole mediated coupling in Sr2Nb2O7 for visible light photocatalysis

The band gap reduction and effective utilization of visible solar light are possible by introducing the anionic holehole mediated coupling in Sr 2 Nb 2 O 7 . By using the first principles calculations, we have investigated the mono- and co-anionic doping (S, N and C) in layered perovskite Sr 2 Nb 2 O 7 for the visible-light photocatalysis. Our electronic structure and optical absorption study shows that the mono- (N and S) and co-anionic doped (NN and CS) Sr 2 Nb 2 O 7 systems are promising materials for the visible light photocatalysis. The calculated binding energies show that if the holehole 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, (NN) and (CS) in Sr 2 Nb 2 O 7 can harvest a longer wavelength of the visible light spectrum as compared to the pure Sr 2 Nb 2 O 7 for efficient photocatalysis. Band gap engineering in Sr 2 Nb 2 O 7 layered structure by anionic doping would be promising for water splitting via visible-light driven photocatalysis.