Ag改性TiO_2催化剂的制备、表征及其甲苯气相光催化降解性能

Synthesis,Characterization and Photocatalytic Performance of Ag-modified TiO_2 Catalysts for the Degradation of Gas-phase Toluene

用溶胶-凝胶法制备Ag改性的TiO2催化剂,并用XRD、SEM、BET、O2-TPD和UV-Vis DRS等测试手段对其进行表征.结果表明,与TiO2相比,所制备催化剂颗粒直径明显减小,比表面积明显增大,对可见光的吸收明显增强,同时出现了表面吸附氧和Ag电子捕获中心.甲苯气相光催化降解结果显示,当Ag与Ti的摩尔比(nAg/nTi)为1.6%时,甲苯单程降解率达到42.9%.焙烧温度提高,使催化剂从单一锐钛矿相向锐钛矿、金红石混合相转变,适量比例的锐钛矿相和金红石相共存,能减少电子-空穴对复合几率,提高催化剂的甲苯降解活性.

Ag-modified TiO2 catalysts were synthesized by sol-gel method and characterized by XRD, SEM, BET, O2-TPD and UV-Vis DRS. The results showed that the Ag-TiO2 catalysts demonstrated smaller particle sizes, larger specific surface areas and higher absorbing ability in visible light when compared with TiO2 catalyst. The surface adsorbed oxygen and Ag electron trapping center also appeared on the Ag-TiO2 catalysts. The single-pass degradation rate of toluene reached 42.9% when the Ag/Ti atomic ratio was 1.6%. The catalysts were transfered from pure anatase phase to anatase-rutile composite phase when the calcination temperatures were increased. The coexisting of anatase phase and rutile phase with appropriate ratio can reduce the recombination probability of the electron-hole pairs and enhance the toluene degradation activities.