Facile Synthesis of Defective TiO 2-x Nanocrystals with High Surface Area and Tailoring Bandgap for Visible-light Photocatalysis

A facile hydrothermal approach has been developed to prepare defective TiO 2-x nanocrystals using Ti(III)-salt as a precursor and L-ascorbic acid as reductant and structure direction agent. The prepared TiO 2-x nanocrystals are composed of a highly crystallized TiO 2 core and a disordered TiO 2-x outer layer, possessing high surface area, controlled oxygen vacancy concentration and tunable bandgap via simply adjusting the amount of added L-ascorbic acid. The defective TiO 2-x shows high photocatalytic efficiency in methylene blue and phenol degradation as well as in hydrogen evolution under visible light, underlining the significance of the present strategy for structural and bandgap manipulation in TiO 2 -based photocatalysis.