Preparation And Performance Study Of The Nano-composite Tio <sub> 2 </ Sub>

Titanium dioxide coated silicon dioxide composite photocatalysts were prepared via sol-gel method from tetrabutyltitanate and TEOS. The influence of calcinated time, calcinated temperature, the molar ratio of the reactants,the quantity of the catalyzer on the as-prepared samples was investigated via XRD, DTA and SEM, and the acting mechanisms of different methods were discussed. The results indicated that the crystalline size of TiO₂ in the composite is12.3nm, and it's specific surface area reached 185.32m²/g.Their photocatalytic activities were valuated by the probe reaction of methly orange degradation.The degradation rate of methly orange is 88.3% after a 3-hour photocatalytic treatment and that composite photocatalysts still show high photocatalytic activity of 73.2% methy orange degradation rate after a twelve 3-hour photocatalytic treatment.The composite TiO₂-SiO₂ films were fabricated on quartz glass via sol-gel method according to the foregoing result. The rims were treated by programming calcinations. The influence of temperature rising rate, calcinated temperature, the molar ratio of the reactants on the as-prepared samples also was investigated via XRD, SEM, DTA, and microscope. It was found that the composite films have good property of heat-resistant.The photocatalytic activity of composite films was a little lower than SiO₂-TiO₂ composite powders, but much higher than pure TiO₂. The degradation rate of methly orange is 82.1% after a 3-hour photocatalytic composite films treatment. Compare with composite powders in repetitive experiment, composite film photocatalysts show furthermore stabilizaing and higher photocatalytic activity. The degradation rate of methy orange after a twelve-times and 3-hour photocatalytic treatment reduced from 82.1% to 79.8%, while the composite powders' activity reduced from 88.3% to 73.2%.It can be estimated that composite films avoid the occurrence of defilade among photocatalysts, so the using ratio of lamp-house can be boosted, whice makes the photocatalytic activities improved.