Synergistic Effect of Y Doping and Reduction of TiO 2 on the Improvement of Photocatalytic Performance.

Pure TiO 2 and 3% Y-doped TiO 2 (3% Y-TiO 2 ) were prepared by a one-step hydrothermal method. Reduced TiO 2 (TiO 2 -H 2 ) and 3% Y-TiO 2 (3% Y-TiO 2 -H 2 ) were obtained through the thermal conversion treatment of Ar-H 2 atmosphere at 500 °C for 3 h. By systematically comparing the crystalline phase, structure, morphological features, and photocatalytic properties of 3% Y-TiO 2 -H 2 with pure TiO 2 , 3% Y-TiO 2 , and TiO 2 -H 2 , the synergistic effect of Y doping and reduction of TiO 2 was obtained. All samples show the single anatase phase, and no diffraction peak shift is observed. Compared with single-doped TiO 2 and single-reduced TiO 2 , 3% Y-TiO 2 -H 2 exhibits the best photocatalytic performance for the degradation of RhB, which can be totally degraded in 20 min. The improvement of photocatalytic performance was attributed to the synergistic effect of Y doping and reduction treatment. Y doping broadened the range of light absorption and reduced the charge recombination rates, and the reduction treatment caused TiO 2 to be enveloped by disordered shells. The remarkable feature of reduced TiO 2 by H 2 is its disordered shell filled with a limited amount of oxygen vacancies (O V s) or Ti 3+ , which significantly reduces the E g of TiO 2 and remarkably increases the absorption of visible light. The synergistic effect of Y doping, Ti 3+ species, and O V s play an important role in the improvement of photocatalytic performances. The discovery of this work provides a new perspective for the improvement of other photocatalysts by combining doping and reduction to modify traditional photocatalytic materials and further improve their performance.