A Study On The Preparation Of Nanometer TiO₂/SiO₂ Composite Powder And Its Photocatalytic Activity

In recent years, semiconductor photocatalysts have evoked tremendous interest in light-stimulated degradation. Nanometer TiO₂ photocatalyst has been proved to have outstanding performance. It can treat waste water and exhaust gas, kill bacteria and viruses. So it can be used to treat waste liquids, purify air, and etc. Thus, it has great practical value to improve the photocatalytic performance of Titania and apply it to environmental protection.In the paper, TiO₂ and TiO₂/SiO₂ composite powders were made by sol-gel technique based on the predecessor's studies. The composition, micro-structure and properties of the prepared TiO₂/SiO₂ powders were characterized by XRD, XPS, BET, FT-IR, and so on. The effects of composition and heat treatment on the transformation temperature between the anatase and rutile phase, as well as the doping of SiO₂ on the photocatalytic degradation of methyl orange were examined.Results showed that the size of doped TiO₂ powders was in the range of 1-50 nm. And their photocatalytic performance was affected by the amount of SiO₂ dopant, heat treatment temperature, and others. The SiO₂ doped TiO₂ heat treated at 550 ℃ demonstrated the highest photocatalytic performance: methyl orange solution was 64.85% decomposed in 2 hour, comparing to that only about 15% decomposed without SiO₂. Proper SiO₂ doping and heat treatment temperature can greatly improve photocatalytic performance of titania .