Photocatalytic activity of ZnO/GaP1−xNx for water splitting

Abstract

The phosphidation of a ZnO/GaN solid solution photocatalyst enhanced significantly its activity for water splitting. The photocatalysts were heated with phosphorus in a vacuum-sealed quartz tube. Activation due to phosphidation was restricted within the narrow temperature range of 823–873 K, and varying amounts of P were added to the solid solution. In addition to X-ray diffraction peaks due to ZnO/GaN, active phosphide ZnO/GaN provided a single GaP peak with diffraction angles higher than normal GaP by 2θ = 0.20–0.44°, indicative of the formation of a GaP_1−xN_x alloy system. The diffraction peaks were simulated using first principles Ab inito calculations on molecular models of Ga₃₂P_32−yN_y. The comparison with experimental shifts showed that the highest activity was induced in an x range of 0.034–0.074 of GaP_1−xN_x.