溶胶-凝胶法制备CdS/TiO_2光催化剂及其催化分解H_2S制氢的研究

Photodecomposition of H_2S to produce H_2 over CdS/TiO_2 composite photocatalysts prepared by Sol-gel method

以钛酸四丁酯为钛源、以硫脲为硫源,采用溶胶-凝胶法制备CdS/TiO_2复合光催化剂,采用X射线衍射、紫外-可见漫反射光谱对催化剂进行表征,考察CdS与TiO_2的摩尔比对CdS/TiO_2复合光催化剂光催化(>400 nm)分解硫化氢制氢性能的影响。表征结果显示,该方法制得的复合光催化剂的X射线衍射峰中TiO_2的特征峰并不明显,CdS的特征峰随摩尔比的变化比较明显,紫外-可见漫反射光谱中,复合催化剂在可见光区的吸收边蓝移。在制氢反应中,该复合光催化剂的产氢性能优于纯CdS,当CdS与TiO_2摩尔比为1/2时,产氢速率为822.92μmol/(h·g)。

The CdS/TiO_2 composite photocatalysts were synthesized by sol-gel method using etrabutyl titanate and thiourea as reactants and characterized by XRD,UV-Vis. In this paper,we also studied the influence of the molar ratios of CdS/TiO_2 to the performence of composite photocatalysts on decomposing H_2S into H_2 under visible light(λ > 400 nm). Characterization showed that TiO_2 characteristic peaks in the X-ray diffraction peak of the composite photocatalysts is not obvious,that characteristic peaks of CdS varied significantly with the molar ratio. UV-Vis showed that the absorption edge of composite photocatalysts exhibited blue-shift in visible region. The photocatalytic avtivity of CdS/TiO_2 composite catalyst was higher than that of CdS,when the molar ratio of CdS/TiO_2 was 1 ∶ 2,and the hydrothermal temperature was 200℃,the composite photocatalyst exhibited better activity: the hydrogen production rate was 4955. 36μmol/h g.