表面光催化还原铁对TiO_2/SiO_2光催化活性的影响  

Influence of Fe deposition on photocatalytic activity of TiO_2/SiO_2 composite photocatalyst

作　　者：黄琮[1] 王良焱[1] 徐悦华[1] 李新军[1] 郑少健[1] 李芳柏[1] 

机构地区：[1]中国科学院广州能源研究所,广州510070

出　　处：《中国有色金属学报》2003年第3期793-796,共4页The Chinese Journal of Nonferrous Metals

基　　金：广东省自然科学基金重点资助项目 (0 10 873) ;广东省科技计划基金资助项目 (A30 40 30 1)

摘　　要：用表面光催化还原铁法对TiO2 /SiO2 复合氧化物进行改性 ,并在改性后用XRD ,TEM进行化学状态、晶体组成与颗粒大小分析。通过对亚甲基蓝的降解揭示表面光还原对催化剂活性的影响。结果表明 :经过表面光催化还原铁法改性的催化剂活性要高于未改性的 ,随着表面还原Fe量的增加 ,催化活性增加。但n(Fe)∶n(Ti) >1.0 %后 ,催化性能急剧下降 ,最佳值为 1.0 %。讨论了Fe杂质对光生载流子分离效率的影响及其影响光催化剂活性的机理。Fe3 + 和Fe2 + 共同存在 ,Fe3 + 是光生电子的捕获阱 ,Fe2 + 是光生空穴的捕获阱 ,在二者的协同作用下 ,载流子得到有效分离 ,催化活性得到提高。TiO 2/SiO 2 composite photocatalyst is modified with Fe using depositing method. The physical and chemical characteristics of the modified photocatalyst were described by X-ray diffraction (XRD) measurement, transmission electron microscopic technique (TEM) and methylene blue (MB) degradation. According to crystal field theory, Fe 3+ is beneficial to photo-induced electrons trapping and migration while Fe 2+ can improve the charge separation by trapping the photo-induced holes. With the coexistence of Fe 2+ and Fe 3+, the activity of modified photocatalyst is enhanced greatly. The results show that the properties of modified photocataysts by deposition are more superior than that of unmodified one and the optimum deposition quantity is 1%(n(Fe)∶n(Ti)).

关 键 词：TiO2/SiO2复合氧化物 光催化活性 表面光催化还原铁法 XRD TEM 光催化剂 

分 类 号：O643.36[理学—物理化学]