Preparations and Environmental Application of TiO2 Photocatalysts Supported on Different Substrates via Sol-gel Method

Jian Yuan
Research Center for Combustion and Environment Technology, Shanghai Jiao Tong University

Jianwei Shi
Research Center for Combustion and Environment Technology, Shanghai Jiao Tong University

Mingxia Chen
Research Center for Combustion and Environment Technology, Shanghai Jiao Tong University

Hai Hu
Research Center for Combustion and Environment Technology, Shanghai Jiao Tong University

Guangtao Zheng
Research Center for Combustion and Environment Technology, Shanghai Jiao Tong University

Wenfeng Shangguan
Research Center for Combustion and Environment Technology, Shanghai Jiao Tong University

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     Last modified: February 16, 2006

Abstract
In recent years, photocatalytic degradation of various kinds of organic pollutants using semiconductor TiO2 as photocatalyts have been extensively studied. Since the organic pullutants could be completely decomposed into CO2 and H2O, photocatalytic method should be one of the most effective means in dealing with the problem of environmental pollution.

Most of the studies about the photocatalytis of TiO2 are focused on powder TiO2. But for most applications, there exist a tough problem of post treatment separation in the mixture. This could be overcome by immobilizing TiO2 particles as thin films on solid substrate. But film-type photocatalysts normally have lower surface areas than powder ones. The decrease of surface area may seriously impair the photocatalytic activity of TiO2. On the other hand, the interaction between TiO2 film and the surface of different substrates could also have different effects on the photocatalytic process.

In this paper, we tried to coat TiO2 films on two different substrates, silica gel particle and foam metal nickle, by sol-gel method. Both of these substrates have relatively large surface area compared to other reported substrates such as glass beads and stainless web nets. Thus the supported TiO2 is good candidate for air cleaning. The photocatalytic activity of the samples was evaluated by the photocatalytic degradation efficiency of gaseous acetaldehyde. XRD, SEM and ATM were used to characterize the crystallization and the surface morphology of the coated TiO2. Based on the discussions and results of the different factors on the photocatalytic process, the optimal preparation conditions in this paper could give ideal samples for commercial applications.