TiO2/SiO2复合光催化剂制备工艺参数优化及其表征

先以无机钛盐、硅酸盐为原料制取聚合硅酸硫酸钛,再通过液相水解法制得TiO2/SiO2复合光催化剂,并用SEM、XRD、BET和甲基橙脱色率对复合光催化剂进行表征。结果表明,TiO2/SiO2复合光催化剂制备优化工艺参数为:Ti(SO4)2作钛源、Ti/Si摩尔比为12∶1、水解反应pH值为6、煅烧温度为650℃,以此条件制备的复合光催化剂对甲基橙脱色率可达98.6%以上;TiO2/SiO2复合光催化剂为一种分散均匀的纳米级球形颗粒,其成分为以锐钛矿为主的TiO2,SiO2的复合有效抑制了TiO2晶粒的生长,同时提高了TiO2的热稳定性。

Preparation and photocatalytic activities of TiO2/SiO2 composite photocatalysts by liquid phase hydrolysis

TiO₂/SiO_2composite photocatalysts were prepared by controlling the hydrolysis of inorganic titanium salts and silicates and then characterized by scanning electron microscope, BET surface area and X-ray diffraction spectra techniques. The effects of titanium source, ratio of titanium and silicon, pH value and calcination temperature on the photocatalytic activity of the photocatalysts were studied during photodegradation of methyl orange in aqueous solution. The results show that the degradation rate of methyl orange can reach 99.9% after oxidation for 30minutes by the photocatalyst prepared under the best conditions. Matter analysis shows that TiO₂/SiO_2composite photocatalysts were nanometre spheric particles, which disperse evenly, have large surface area and form anatase TiO_2mostly. The compound of SiO_2inhibits the growth of TiO_2crystal particles effectively and at the same time improves the stability of TiO₂.