Effective water splitting using CuOx/TiO2 composite films: Role of Cu species and content in hydrogen generation

We have fabricated a series of CuOx/TiO2 composite films composed of TiO2 nanorods and CuOx nanopariticles with copper content in the range of 0-4.75 at.% by a facile magnetron sputtering method for hydrogen generation from water splitting. By virtue of the one-dimensional TiO2 nanostructures, all the nanorods films show excellent photocatalytic activity. Especially, there appear to be an optimum Cu content of 2.72 at.% giving the H-2 evolution rate of 53 mmol m(-2) h(-1), which is about 15 times higher than that of pristine anatase TiO2 nanorods film. To evaluate the effect of foreign copper on the photocatalytic properties, comprehensive structural, morphology and surface characterizations of catalysts have been carried out. It is found that CuO is an unstable species which is inevitably reduced to Cu2O during the initial stage of photocatalytic reaction, and the occurrence of highly disperse Cu2O species is responsible for the improved photocatalytic activity. (C) 2016 Elsevier B.V. All rights reserved.