溶胶-凝胶法制备La2Ti2O7/HZSM-5及其光催化活性

摘要

La2Ti2O7/HZSM-5 photocatalysts were prepared by sol-gel method, and its photocatalytic activity was studied.The results show that the original crystal phase of La2Ti2O7 is not changed after loading La2Ti2O7 on HZSM-5,and is still perovskite structure.La2Ti2O7 is dispersed on the surface of HZSM-5 after loading to apparent increasing specific surface area and formation of new mesoporous structure.The growth of La2Ti2O7 is constrainted by HZSM-5, resulting in the reduction of grain size.The absorption boundary has a blue shift and the band gap increases with decreasing La2Ti2O7 loading content.Binding energies of La3d and O1s electrons move to higher energy after loading La2Ti2O7 on HZSM-5.La2Ti2O7/HZSM-5 has enhanced photocatalytic activity as compared to La2Ti2O7.91.8% of the reactive brilliant red(RBR) X-3B is decolorized on 70%La2Ti2O7/HZSM-5 after 120min of UV irradiation, while only 31.7% of the dye is removed on La2Ti2O7.%采用溶胶-凝胶法制备La2Ti2O7/HZSM-5光催化剂,并对其光催化活性进行研究.结果表明:La2Ti2O7经HZSM-5分子筛负载后,并未改变原有晶相,仍为单斜晶系钙钛矿结构.负载后的La2Ti2O7分散在分子筛表面,催化剂的比表面积大幅增加并形成新的中孔结构.HZSM-5制约了La2Ti2O7的生长,导致晶粒尺寸减小.材料的光谱吸收边界随负载量的减小而发生蓝移,禁带宽度增大.负载样品中La3d和O1s的电子结合能增大.La2Ti2O7/HZSM-5比纯La2Ti2O7具有更高的光催化活性.经紫外光照120min后,活性艳红X-3B在70%La2Ti2O7/HZSM-5上的总脱色率为91.8%,而在La2Ti2O7上仅为31.7%.