One-step synthesis of nonstoichiometric TiO2 nanorod films for enhanced photocatalytic H-2 evolution

摘要

The realization of one-dimensional nanostructures or Ti3+ self-doping in TiO2 photocatalysts has proven to be an effective approach for significantly improving their photocatalytic performance. Herein, a series of nonstoichiometric anatase TiO2 nanorod films were deposited at 50-500 degrees C by a facile one-step magnetron sputtering method. The correlation between the microstructures and the photocatalytic H-2 production abilities of the films was studied. It is found that, by increasing the deposition temperature, the as-sputtered TiO2 grains transformed from quasi-spherical to rod-like structures while the concentration of the Ti3+ species decreased gradually. Thus, by virtue of the collaboration between nanostructure engineering and defect engineering, the sample deposited at 300 degrees C showed a maximum H-2 generation rate of 1874 mol m(-2) h(-1), which was about 134 times higher than that of a Degussa P25 powder film (14 mol m(-2) h(-1)). Furthermore, the stoichiometric TiO2 shell formed on the surface of TiO2 nanograins protected the defective TiO2-x core from further oxidation, resulting in an excellent photocatalytic stability of the films. The possible film growth and photocatalytic reaction mechanisms over the Ti3+ doped TiO2 nanorod films have been investigated. Our work provides a facile route to fabricating a high-efficiency defect-based TiO2 or other transition metal oxide nanostructures with a controlled morphology for solar energy conversion.