Ag-TiO_2/SnO_2纳米薄膜的制备及其光催化降解罗丹明B的性能

Preparation and Photocatalytic Activity for Rhodamine B of Ag-TiO_2/SnO_2 Thin Films

以光还原法沉积Ag修饰TiO2/SnO2,制备Ag-TiO2/SnO2纳米薄膜,讨论紫外光照时间、光照强度、AgNO3浓度等工艺条件对光催化活性的影响。用XRD和SEM对薄膜的结构、表面形貌和化学组成进行表征,以罗丹明B为模拟污染物对光催化性能进行测定。结果表明,最佳条件下制备的Ag-TiO2/SnO2薄膜,Ag担载量为0.51%(at%),Ag簇直径在30～90nm之间。薄膜具有较高的光催化活性,对罗丹明B的降解率是修饰前TiO2/SnO2薄膜的1.92倍,是相同质量TiO2/ITO薄膜的2.54倍。催化活性的提高,源于反应机制的改变。薄膜中Ag-TiO2异质结的引入,一方面进一步促使光生电荷分离,另一方面加速了氧气与激发电子的还原反应。

Silver-modified TiO2/SnO2 thin films （Ag-TiO2/SnO2 thin films） were prepared by the photodeposition method. The effects of preparation conditions on the photocatalytic activity of Ag-TiO2/SnO2 thin films were discussed. The surface morphology, chemical composition and structure of the films were characterized by SEM and XRD, and its photocatalytic properties were evaluated with Rhodamine B as model compound. The results show that the optimum content of Ag on the film surface was 0.51at% and the diameter of Ag particles was about 30-90 nm. The photocatalytic degradation rate of Ag-TiO2/SnO2 film is 1.92 times and 2.54 times higher than the TiO2/SnO2 film and the TiO2/ITO film, respectively, mainly duo to the change in the reaction mechanism. The heterojunction of Ag-TiO2 in Ag-TiO2/SnO2 film efficiently promoted the separation of charges and accelerated the reaction of excited electrons and oxygen relatively to TiO2/SnO2 film in photocatalytie degradation for Rhodamine B.