Multichannel charge separation promoted ZnO/P25 heterojunctions for the photocatalytic oxidation of toluene

Abstract

The fabrication of multicomponent heterojunctions is an effective strategy to improve the performance of TiO2 based photocatalysts. We provide a new strategy for improving the charge separation and photocatalytic performance of ZnO/TiO2 composites by the formation of multichannel charge separated heterojunctions. ZnO/P25 composites were prepared by an incipient wetness impregnation method, and applied for the photocatalytic destruction of gaseous toluene. The ZnO/P25 composites consist of anatase TiO2 (ATiO2), rutile TiO2 (RTiO2) and hexagonal zincite structures. The parasitic phase of ZnO in P25 leads to the formation of ZnO(002)/ATiO2(101)/RTiO2(110) heterojunctions that exhibit enhanced light absorption and improved multichannel electron/hole separation. ZnO/P25 heterojunctions can completely oxidize toluene into CO2 and H2O under ultraviolet light irradiation at room temperature, and show enhanced photocatalytic activity in comparison with P25 owing to the efficient electron-hole separation. Such a multichannel charge separated design strategy may provide new insight into the design of highly effective photocatalysts and their potential technological applications.