Heterojunction formation on InVO4/N-TiO2 with enhanced visible light photocatalytic activity for reduction of 4-NP

In this study, we report the preparation of a new heterojunction photocatalyst of InVO4/N-TiO2 (labeled as TNI) by a simple coupled process using sol gel method. Compared to the weak response with pure N-TiO2, and InVO4, the new hybrid materials were found to significantly enhance photoreduction of 4- Nitrophenol (4-NP) to 4-Aminophenol (4-AP) under visible light. The increase in photocatalytic activity was attributed to several factors such as the development of a synergistic effect between N-Doped TiO2 and InVO4 materials allowing a greater absorption of light in the visible region of the solar spectrum and to the formation of heterojunctions in the TNI materials which improve the separation of photogenerated electron-hole pairs and decreases the recombination process. Based on the characterization results and the photoactivity experiments we propose a general scheme describing the 4-NP photocatalytic reduction mechanism using the TNI composites. Finally the great stability of the heterostructures was evaluated by means of photocatalysts recycling tests.