以偏钛酸为原料制备高效负载型纳米TiO_2/活性炭光催化剂

High Performance Supported Photocatalyst of Nano-TiO_2/Activated Carbon from Metatitanic Acid

以颗粒活性炭(AC)为载体,偏钛酸为钛源,采用浸渍-水热法制备负载型TiO2光催化剂,在300～800℃下热解处理.利用X射线衍射、扫描电镜、拉曼光谱和氮气吸附对催化剂样品进行了表征.以甲基橙(MO)降解为模型反应,对负载型TiO2光催化性能进行评价.结果表明,经600℃焙烧的样品具有最佳光催化性能,为锐钛矿晶型,负载于活性炭上的TiO2是由30～50nm的球型颗粒组成.负载型TiO2/AC光催化剂的光催化活性高于相同方法制备TiO2和AC混合物及商业化产品Degussa P25与活性炭混合物,光降解反应符合一级反应动力学方程.催化剂重复使用5次其光催化活性基本保持不变.

TiO2 phototcatalysts deposited on activated carbon （AC） were prepared by a dip-hydrothermal method using an aqueous solution of metatitanic acid as a precursor, and calcined in 300-800℃. The samples were characterized by X-ray diffraction （XRD）, scanning electron microscopy （SEM）, Raman spectrum and nitrogen adsorption. The photocatalytic activity of samples was evaluated by degradation of methyl orange （MO） as target pollutant. The results showed that uniformly dispersed TiO2 particles of anatase type were deposited on the activated carbon surface. TiO2/AC calcined at 600℃ exhibited the best performance. For the comparison, the same degradation procedure was carried out for two mixtures of commercial TiO2 （Degussa P25） with AC and synthetic TiO2 with AC. It was found that MO photocatalytic degradations were of apparent first order and TiO2/AC had higher photocatalytic efficiency than the two mixtures. The efficiency of TiO2/AC photocatalyst for MO degradation was hardly changed after 5-cycle use.