Preparation of (Ga1−xZnx) (N1−xOx) solid-solution from ZnGa2O4 and ZnO as a photo-catalyst for overall water splitting under visible light

A solid-solution of GaN and ZnO (Ga1−xZnx) (N1−xOx), as a visible-light-driven photo-catalyst for overall water splitting, is successfully prepared using both ZnGa2O4 and a ZnGa2O4–ZnO mixture. The photo-catalytic activity of the catalyst is found to be dependent on both the Zn/Ga ratio of the starting material and the nitridation time, because both factors affect the crystallinity and atomic composition of the final (Ga1−xZnx) (N1−xOx) material. It is also revealed that the addition of ZnO promotes crystallization of the catalyst and controls the zinc concentration, thereby improving activity. By adjusting these two preparation parameters, it is possible to obtain a material with optimal crystallinity and atomic composition for overall water splitting under visible light (λ > 400 nm).

Graphical abstractA solid-solution of GaN and ZnO (Ga1−xZnx) (N1−xOx), is successfully prepared by nitriding ZnGa2O4 powder at 1123 K for 15 h under a flow of NH3, and the addition of an appropriate amount of ZnO to the starting material is shown to improve the photo-catalytic activity of the final product substantially.Figure optionsDownload full-size imageDownload as PowerPoint slide