Preparation of silicon-doped TiO2 fiber and supported TiO2 and comparison study of their photocatalytic activity

Abstract

The Si-doped TiO2 fiber and supported TiO2 were prepared by sol–gel method and steam heat treatment, by using titanic chloride (TiCl4) as titanium source, tetraethoxysilane as silicon source and alumina foam ceramic as carrier. The samples were characterized by X-ray diffraction, scanning electron microscope, and ultraviolet–visible spectrophotometer. Methyl orange solution (with a concentration of 20 mg/l) was chosen for photodegradation. The influences of calcination temperature, dopant concentration and solution pH value on the decolorization efficiency of methyl orange were studied systematically. The photoactivity of TiO2 fiber and supported TiO2 were also compared. The results showed that the optimal conditions for preparing the anatase TiO2 with good photocatalytic activity was: calcination temperature 700 °C, calcination time 2 h, Si doping amount 20 mol%. Si-doped TiO2 fiber and supported TiO2 exhibited high photocatalytic efficiency on the degradation of methyl orange solutions in condition of strong acid (pH = 2) and strong alkaline (pH = 13.5). TiO2 fiber and supported TiO2 are easy to be separated and reused in water treatment, so they have high practical value.