(1. 中国科学院 广州能源研究所， 广州 510070;
2. 广东省生态环境与土壤研究所，
广东省农业环境综合治理重点实验室， 广州 510650)
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。
关键词: TiO2/SiO2；表面还原； Fe
TiO2/SiO2 composite photocatalyst
（1. Guangzhou Institute of Energy Conversion,
Chinese Academy of Sciences,Guangzhou 510070, China;
2. Guangdong Key Laboratory of Agricultural Environment Pollution Integrated Control,
Guangdong Institute of Eco-Environment and Soil Science, Guangzhou 510650, China）
Abstract:TiO2/SiO2 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, Fe3+ is beneficial to photo-induced electrons trapping and migration while Fe2+ can improve the charge separation by trapping the photo-induced holes. With the coexistence of Fe2+ and Fe3+, 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)).
Key words: TiO2/SiO2; deposition; Fe
