Highly Active Photocatalyst of CuO x Modified TiO 2 Arrays for Hydrogen Generation

The photocatalytic performance and the involved mechanism of copper modified TiO2 have attracted a wide range of scientific interest in recent years. In this study, we fabricate CuOx/TiO2 photocatalysts by depositing Cu, Cu2O, and CuO on the surface area of hierarchical TiO2 arrays using magnetron sputtering method. These CuOx/TiO2 photocatalysts exhibit excellent photocatalytic performance, with H2 generation rate of 30 mmol m-2 h-1 for CuO/TiO2, 37 mmol m-2 h-1 for Cu2O/TiO2 and 53 mmol m-2 h-1 for Cu/TiO2. We further study the composition evolution of CuOx during the photocatalytic reaction process to illustrate the actual active copper species. It is found that CuO is easily photo-reduced to Cu2O and the latter can be further reduced to metallic Cu under irradiation in the solution. In the steady stage of photocatalytic reaction, the photo-induced TiO2/Cu2O/Cu three-phase system facilitates the separation of photo-generated carriers through the migration of electrons in both TiO2 and Cu2O to metallic ...