Influence of preparation methods on the structure and catalytic performance of SnO_2-doped TiO_2 photocatalysts

摘要

The influence of preparation methods on the physicochemical and photocatalytic activity of Sn~(4+) doped TiO_2 is mainly investigated in this work. Five different preparation methods have been used to synthesize SnO_2-TiO_2 catalysts: sol-gel method (SGM), sol-hydrothermal method (SUM), co-precipitation method (CM), coprecipitation-hydrothermal method (CHM) and hydrothermal method (HM). Their differences in the structures, chemical composition, particle sizes, specific areas, pore size distribution and energy band structure feature were characterized by XRD, XRF, FESEM, LRS, N_2-physisorption and UV-vis DRS, respectively. Furthermore, the photocatalytic activity of the as-synthesized products was evaluated by monitoring the degradation of methyl blue (MB) solution under UV illumination. It is shown that the Ti_(0.75)Sn_(0.25)O_2 catalyst prepared by the sol-hydrothermal method has the optimum catalytic activity for degradation MB, which is attributed to the optimal crystallization, homogeneous surface, uniform particles, good dispersibility and enhanced light absorption. Moreover, this is a novel method for the synthesis of SnO_2-TiO_2 photocatalyst firstly combining sol-gel and hydrothermal synthesis. Our findings demonstrate that the new way could be utilized in preparations of other catalysts for promising development of high-performance photocatalysts in the environmental applications.