酸对TiO_2结构和光催化性能的影响

以H2SO4,HCl和一水合柠檬酸作酸催化剂,采用溶胶-凝胶法合成了纳米TiO2光催化剂。通过XRD,TEM,HR-TEM,Uv-Vis和FT-IR等分析手段对样品进行表征。以亚甲基蓝(MB)为目标降解物,对催化剂的光催化性能进行评价。研究结果表明,酸对TiO2的结构和性能有很大的影响:以H2SO4做催化剂时,TiO2颗粒分布均匀,粒径在7~12nm之间,全为锐钛矿相;以HCl作催化剂时,TiO2的粒径约为20nm,全为锐钛矿相;而以一水合柠檬酸作催化剂时,TiO2的粒径较大,约为30nm,且团聚严重,为锐钛矿相和金红石相的混合相。以H2SO4作催化剂制备的TiO2光催化活性最好。

Influence of acid catalyst on crystalline microstructure and photocatalytic property of Nano-TiO2

Nano-TiO2 was prepared by sol-gel method using sulfuric acid,hydrochloric acid or citric acid monohydrate as the acid catalyst.The products were characterized by XRD, TEM,HR-TEM,Uv-Vis and FTIR.The photocatalytic activity of the products was carried out by photocatalytic decomposition of methylene blue（MB）.The results indicate that the structures and properties of the nanocrystals are determined by the acid catalyst：When the catalyst is sulfuric acid,TiO2 particles distribute evenly with the size of 7~12 nm and the crystalline type is only anatase.When the catalyst is hydrochloric acid,the particle size of the TiO2 is about 20 nm,with anatase phase only.When the catalyst is citric acid mono-hydrate,the TiO2 particle size is bigger,which is about 30 nm,aggregated seriously,and the phases are mixed with anatase and rutile phase.The product made by sulfuric acid has the highest photocatalytic activity.