Study of adsorption-assisted photocatalytic oxidation of benzene with TiO2/SiO2 nanocomposites

Authors: Zhi Liu, Feitai Chen, Pengfei Fang, Shaojie Wang, Yuanpeng Gao, Feng Zheng, Yang Liu, Yiqun Dai

Abstract:
TiO₂/SiO₂ composite photocatalysts were prepared via a simple reflux-stir process. These composites exhibit a highly distributed state between TiO₂ (P25) and fumed silica (SiO₂) nanoparticles, and the SiO₂ nanoparticles surround the TiO₂ crystalline grains closely. The photoactivity ofthe composites was investigated by photocatalytic oxidation of gaseous benzene. By adjusting the Ti/Si mole ratio from 50:1 to 1:1, the photocatalytic efficiency of the TiO₂/SiO₂ composites ascends firstly and then decreases. The optimum Ti/Si mole ratio is 30:1, and the photocatalytic efficiency reaches 92.3% within 120 min, which is 6.8 times higher than that of P25. Additionally, recycled tests which performed ten times demonstrate the nanocomposites possess a pretty good recyclability. The excellent photocatalytic performances can be chiefly attributed to the good dispersion state between TiO₂ and SiO₂. The special structure helps the formation of a high population of hydroxyl groups on the catalysts surface, and these hydroxyl groups greatly improve the charge separation efficiency and the reaction rate. In addition, the enhanced adsorption powers to water vapor and benzene also contribute to the high photoactivity.

Keywords:
TiO₂
SiO₂
Adsorption
Benzene
Hydroxyl radicals

Published in: Applied catalysis A: General  (Volume 451, Pages 1-288, 31 January 2013)

Publisher: Elsevier

ISSN Information: 0926-860X

Study of adsorption-assisted photocatalytic oxidation of benzene with TiO2/SiO2 nanocomposites

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