Improvement of photocatalytic activities of Ag/P25 hybrid systems by controlled morphology of Ag nanoprisms

Constructing hybrid systems with noble metal nanostructures is one known way to improve the poor photocatalysis efficiency of TiO2 under visible light. In our study, two different Ag nanostructures were prepared: (1) Ag nanospheres synthesized by chemical reduction method, and (2) Ag nanoprisms transformed from nanospheres with an additional photo-conversion process. Both Ag-TiO2 hybrid systems were prepared by mixing various concentrations of Ag solutions with commercial TiO2 powder (P25), and they were then utilized as photocatalysts for the photodecolorization test of methyl blue under various light sources (fluorescent, UV light and red LED lamps) irradiations. Results of the photodecolorization tests showed that Ag nanostructures could evidently enhance the photocatalytic activity of TiO2 under different light sources, while an optimal composition of 0.432 wt% Ag nanoprisms/TiO2 displayed superior photocatalytic properties under visible light irradiations (fluorescent and red LED lamps). The enhanced photocatalytic activities could be mainly attributed to the mechanisms of hot electrons injection and resonant energy transfer by the localized surface plasmon resonance of Ag nanostructures and the electronic states favorable of charge separation at the interface between metals and semiconductors. (C) 2017 Elsevier B.V. All rights reserved.