Ag@AgCl-TiO_2-粉煤灰微珠复合光催化剂的制备及其可见光光催化性能

Preparation of Ag@AgCl-TiO_2-Flyash Microspheres Composite Photocatalyst and Its Photocatalytic Property under Visible Light

采用离子交换法在粉煤灰微珠(FMS)表面沉积Ag@AgCl纳米颗粒,制备Ag@AgCl-FMS复合基底,采用水解-沉淀工艺,以TiCl4为钛源在复合基底表面再包覆纳米TiO2薄膜,经500℃煅烧2h后得到Ag@AgCl-FMS-TiO2复合光催化剂.对材料微观形貌、晶体结构、可见光光催化性能进行了表征与测试.结果表明,复合基底表面包覆的TiO2薄膜均匀完整.500℃煅烧后的物相为90%锐钛矿型TiO2和10%金红石型TiO2.复合催化剂料在Ag@AgCl等离子共振效应的作用下,表现出明显的可见光响应,经可见光照射80min后对甲基橙的降解率达99%,5次重复使用对甲基橙的降解率保持在85%.

Ag@AgCl nanoparticles were loaded on the surface of fiyash microspheres （FMS） by ion-exchange method to prepare Ag@AgCl-FMS composite support, then nano-TiO2 thin film was coated on it by hydrolysis precipitation with TiCl4 solution as precursor. After annealing at 500 ℃ for 2 h, the Ag@AgCl-FMS-TiO2 composite photocatalyst was obtained. Its microstructure, crystalline structure and photocatalytic properties under visible light were characterized. The results show that the TiO2 thin film on the substrate is uniform and complete. After calcining at 500 ℃, the material contains of 90% anatase phase and 10% rutile. The composite modified by Ag@AgCl nanoparticles exhibits high photocatalytic activity under visible light, which is caused by the surface plasmon resonance effect of Ag@AgCl. The degradation rate of methyl orange solution can reach 99% after 80 min irradiation under 250 W metal halide lamp. The photocatalyst also shows great stability. Repeated experiments show that the degradation rate of methyl orange solution can still reach 85% after 5 times of using.