SrTiO_3/TiO_2 heterostructure nanowires with enhanced electron-hole separation for efficient photocatalytic activity

摘要

Heterostructure is an effective strategy to facilitate the charge carrier separation and promote the photocatalytic performance. In this paper, uniform SrTiO3 nanocubes were in-situ grown on TiO2 nanowires to construct heterojunctions. The composites were prepared by a facile alkaline hydrothermal method and an in-situ deposition method. The obtained SrTiO3/TiO2 exhibits much better photocatalytic activity than those of pure TiO2 nanowires and commercial TiO2 (P25) evaluated by photocatalytic water splitting and decomposition of Rhodamine B (RB). The hydrogen generation rate of SrTiO3/TiO2 nanowires could reach 111.26 mmol.g(-1).h(-1) at room temperature, much better than those of pure TiO2 nanowires (44.18 mmol.g(-1).h(-1))and P25 (35.77 mmol.g(-1).h(-1)). The RB decomposition rate of SrTiO3/TiO2 is 7.2 times of P25 and 2.4 times of pure TiO2 nanowires. The photocatalytic activity increases initially and then decreases with the rising content of SrTiO3, suggesting an optimum SrTiO3/TiO2 ratio that can further enhance the catalytic activity. The improved photocatalytic activity of SrTiO3/TiO2 is principally attributed to the enhanced charge separation deriving from the SrTiO3/TiO2 heterojunction.