Ag／TiO2复合纳米催化剂的制备和表征及其光催化活性

 采用光还原沉积贵金属法，制备了Ag／TiO2复合纳米催化剂．通过调节溶液的pH值控制TiO2表面负载银的形貌，利用AAS，XRD，TEM和XPS等手段对样品进行了表征．以苯胺氧化为模型反应，考察了Ag／TiO2复合纳米催化剂样品的光催化活性以及银沉积量和沉积形貌对催化剂活性的影响．结果表明，通过调控光还原沉积条件，可在平均粒径为24nm左右的TiO2颗粒上获得3nm左右均匀分散的银粒子；在TiO2上沉积适量的具有较高分散度的金属Ag，能有效提高TiO2对苯胺氧化反应的光催化活性．

Preparation and Characterization of Ag/TiO2 Nanoparticle Catalyst and Its Photocatalytic Activity

Ag/TiO 2 composite nanoparticle catalyst was prepared by photoreductoin-depos ition method. The morphology of silver particles could be changed by controlling pH val ue of the solution, and the well-dispersed silver particles (about 3 nm) were s uccessfully obtained on the surface of TiO 2 nanoparticles(ca 24 nm). The c a talyst samples were characterized by AAS, XRD, TEM and XPS techniques. The photo c atalytic activity of Ag/TiO 2 was measured by using photocatalytic oxidation of aniline as a model reaction, and the effects of Ag loading on the photocatalyti c activity were investigated. The photocatalytic oxidation of aniline indicated that the photocatalytic activity of TiO 2 nanoparticles could be greatly improv ed by depositing appropriate amount of silver on their surface. The morphology o f coated silver had a direct effect on the photocatalytic activity of Ag/TiO 2 catalyst. Well-dispersed silver particles with a proper loading could improve t he photocatalytic oxidation of aniline efficiently.