PW_(11)Cu/TiO_2/SiO_2复合膜的制备及可见光催化性能研究

Preparation and Visible Photocatalytic Performance of PW_(11)Cu/TiO_2/SiO_2 Composite Film

采用溶胶-凝胶法将Keggin型铜取代的杂多酸盐Na_5PW_(11)O_(39)Cu(II)(PW_(11)Cu)负载于TiO_2/SiO_2表面制备出PW_(11)Cu/TiO_2/SiO_2复合膜可见光催化剂,通过UV-Vis DRS、IR和SEM对其进行了表征,考察了焙烧温度和PW_(11)Cu含量对此复合膜光催化活性的影响。实验结果表明,PW_(11)Cu/TiO_2/SiO_2膜具有良好的可见光吸收活性。复合膜中PW_(11)Cu含量越多,膜的光催化活性越高,而焙烧温度增高会使得光催化活性降低。当PW_(11)Cu的含量为3.0 g(40 wt%),焙烧温度为373 K时,其具有最好的可见光催化活性,在250 W可见光下反应3 h,RhB(10μmol·L^(-1))可以达到100%降解,COD去除率达32%(4 h),经过10次循环实验,催化剂的光催化活性仍保持在93%左右。显示出该复合光催化剂对RhB降解具有高效性和较强的稳定性。

The PW11 Cu/TiO2/SiO2 composite film photocatalyst was prepared by loading Keggin-type copper-substituted heteropolyacid salt Na5 PW11 O39 Cu(II)(PW11 Cu) onto the surface of TiO2 and SiO2 using sol-gel method. The PW11 Cu/TiO2/SiO2 composite film photocatalyst were characterized by UV-Vis DRS, IR and SEM.The effect of calcination temperature of PW11 Cu/TiO2/SiO2 film and PW11 Cu content on the photocatalytic activity was investigated. The experimental results showed that the PW11 Cu/TiO2/SiO2 film has excellent absorption capacity of visible light. With the increase of PW11 Cu content, the photocatalytic activity increased.However, the photocatalytic activity decreased as the calcination temperature increased. The film has the best visible light photocatalytic activity when PW11 Cu was 3.0 g(Percentage is 40%) and calcination temperature was 373 K. It was employed to degrade RhB with a concentration of 10 μmol·L^-1 under the irradiation of 250 W xenon lamp, the degradation ratio of RhB was about 100% at 3 h and the COD removal was 32% at 4 h. After 10 times recycles of experiments, the photocatalytic activity of the catalyst remained at about 93%. The results showed that the degradation of RhB by composite photocatalyst had higher efficiency and stability.