Bio-inspired V-TiO2 architectures with regulable surface ultrastructure for visible-light photocatalytic selective oxidation of cyclohexane

Abstract

Photocatalytic selective oxidation of cyclohexane is more energy saving and sustainable when compared with traditional thermal catalysis, but highly effective visible-light photocatalyst for this reaction remains challenging. Herein, vanadium-doped TiO2 was prepared by using a solvent-thermal-assisted biotemplating method, while glycerol was used to regulate the surface ultrastructure of the catalyst. It is found that the use of the biotemplate, regulation of the surface ultrastructure of the catalyst by glycerol, as well as vanadium doping are all beneficial to improve the performance of the photocatalyst. Resultantly, the biotemplated TiO2 doped with 2 % vanadium, which has a needle-like surface ultrastructure (2 %V-CTiO2(g)) achieves the best performance for cyclohexane conversion (0.98 %), which is 7.0, 8.9 and 49 times higher than TiO2 sample without vanadium doping, surface ultrastructure adjustment and biotemplating, respectively. Characterizations and DFT calculations confirm that biotemplating and the use of glycerol endow the sample with unique morphology, oxygen vacancies and high surface area. Doping of vanadium not only changes the band structure of TiO2 but also introduces the interconversion of V4+ and V5+ into the photocatalytic process. This work offers a new approach to the green conversion of cyclohexane.