Oxygen vacancies modified TiO2/Ti3C2 derived from MXenes for enhanced photocatalytic degradation of organic pollutants: The crucial role of oxygen vacancy to schottky junction

Photocatalysis is outstanding for contaminants removal. However, the rapid recombination of photoinduced electron-holes generally restricts its photocatalytic performance. Herein, a novel oxygen vacancies (OVs) modified TiO2(TiO2-x)/Ti3C2 (A-TOTC) photocatalyst was synthesized, in which TiO2-x nanoparticles were in situ grown on Ti3C2 (MXenes) to construct schottky junction for improving the separation efficiency of photogenerated charge carriers. Different annealing duration was applied to control the content of OVs in TiO2 for investigating its role on the photocatalytic performance of A-TOTC. The introduction of OVs dramatically improve the photocatalytic ability of A-TOTC, and the kinetic constant of bisphenol A (BPA) degradation of A-TOTC with optimal oxygen vacancy content was nearly 5.1 and 4.0 times higher than that of TiO2/Ti3C2 and TiO2-x, respectively. The hydroxyl radicals (center dot OH) and superoxide radical (center dot O-2(-)) were the main active substances. The enhanced photocatalytic activity of A-TOTC arises from the decreased of schottky barrier caused by OVs.