Zn掺杂对TiO_2晶相及光催化性能的影响

采用改进的溶胶-凝胶法制备ZnO-TiO2复合催化剂,通过X射线衍射(XRD)、紫外-可见漫反射(UV-Vis DRS)对其微晶结构和光吸收性能进行表征.以甲基橙作为模拟降解物,结果表明,改变水和乙醇的含量以控制溶胶向凝胶陈化的时间影响ZnO-TiO2的催化活性.当n(Zn)∶n(Ti)为3∶15、煅烧温度为500℃时产物催化效率最好,紫外光照5 h,降解率为96.4%.XRD结果显示,ZnO-TiO2主要以锐钛矿相TiO2和立方Zn2TiO4晶相存在,且Zn2TiO4晶相在n(Zn)∶n(Ti)≥3∶15时才会出现.紫外-可见漫反射吸收光谱显示,相比单纯TiO2,Zn O-TiO2吸收边蓝移.

Effect of TiO_2 Doping by Zn on Crystalline Phase and Photocatalytic Activity

ZnO-TiO2 composite catalyst was prepared by modified sol-gel method. The microcrystalline structure and light absorption performance of ZnO-TiO2 were identified by XRD and UV-Vis DRS,respectively. With methyl orange( MO) as the degradation product,the result showed that the photocatalytic activity of ZnO-TiO2 was affected by the conversion time from sol to gel controlled by changing the content of water and ethanol. when the ratio of n( Zn) ∶n( Ti) was 3∶ 15 and calcination temperature was 500 ℃,the degradation of MO was up to 96. 4% under UV irradiation for 5 h. The XRD results confirmed ZnO-TiO2 appeared mostly anatase TiO2 and cubic Zn2TiO4 phases,and the cubic Zn2TiO4 phase was observed only when n( Zn) ∶ n( Ti) ≥3∶ 15. Compared with the pure TiO2,the characteristic absorption threshold of ZnO-TiO2 appeared slight blue shift.