纳米Ag修饰的介孔TiO2微球的合成及光催化性能研究

Synthesis and Photocatalytic Activity of Ag Nanoparticles-decorated Mesoporous TiO2 Spheres

为了提高TiO2的光催化性能,我们通过贵金属-半导体复合的方法合成了纳米Ag修饰的介孔TiO2微球(Ag/m-TiO2)异质光催化剂.研究选用的分步合成法不仅操作简单,而且能够有效控制纳米Ag颗粒的尺寸.形貌和结构表征结果表明,直径小于5 nm的Ag纳米粒子均匀分散在介孔TiO2微球表面,形成异质结构.氮气吸附-脱附测试表明,Ag/m-TiO2材料具有介孔结构和较大的比表面积.性能测试中,本文以亚甲基蓝(MB)为例,系统研究了Ag/m-TiO2材料的紫外和可见光催化能力.结果表明,Ag/m-TiO2材料比介孔TiO2微球(m-TiO2)具有更高的光催化性能,Ag/m-TiO2异质结的存在能够促进光生载流子的转移和分离,进而提高TiO2的光催化性能.本研究的合成方法和贵金属-半导体复合结构的设计对TiO2光催化材料的合成和应用具有一定参考价值.

In order to improve the photocatalytic performance of TiO2,we synthesized nano Ag modified mesoporous TiO2 heterogeneous(Ag/m-TiO2)microsphere photocatalyst by constructing noble metal semiconductor heterojunction. The step-by-step synthesis method is not only easy to operate,but also can effectively control the size of nano Ag particles. The results of morphology and structure characterization show that numerous Ag nanoparticles with diameter less than 5 nm dispersed homogenously onto the mesoporous TiO2 spheres and consequently forms heterostructures. N2 adsorption-desorption measurements indicate that the resultant products were porous with highly specific surface area. Methyl blue(MB)was used as an example to study the photocatalytic activity of Ag/m-TiO2 under UV and visible light. The results show that the Ag/mTiO2 material has higher photocatalytic performance than the mesoporous TiO2(m-TiO2)microspheres. The existence of Ag/m-TiO2 heterojunction can promote the transfer and separation of photogenerated carriers,and then improve the photocatalytic performance. The synthesis method and the design of noble metal-semiconductor composite structure in this study have certain reference value for the synthesis and application of TiO2 photocatalytic materials.