水热法制备CdS/TiO2及其光活性

研究了CdS/TiO₂光催化的耦合效应.以TiO₂、CdCl₂和Na₂S为原料在200 ℃、6 h水热反应条件下一次合成CdS含量不同的CdS/TiO₂，通过XRD、SEM、EDS和IR对样品进行表征，并通过谢乐公式（Scherrer equation）估算出样品晶粒的粒径.XRD图表明CdS/TiO₂为锐钛矿型TiO₂、立方相和六方相CdS的混合相.SEM表明CdS粒径为20～50 nm，TiO₂粒径为50～100 nm.通过罗丹明B(rhodamine B)光降解脱色，表征了样品的光活性，结果表明当CdS∶TiO₂为1.0时，CdS/TiO₂开始出现耦合效应，当CdS∶TiO₂为1.5时，CdS/TiO₂的光活性最强，在30 min内紫外光降解4 mg•L^-1罗丹明B溶液的降解率达74.3%.

Preparation of CdS/TiO2 by hydrothermal method and its photocatalytic activity

The coupled effect of photocatalytic activity of CdS/TiO₂ composite semiconductor was studied.CdS/TiO₂ nano-powders with different ratios of CdS∶TiO₂ from 0.005 to 2.0 were synthesized by the hydrothermal method at 200 ℃ for 6 h using titania, cadmium chloride and sodium sulfide as reactants. The CdS/TiO₂ powders were characterized by XRD, SEM, EDS, IR and the diameter of the particles was evaluated by Scherrer equation. XRD patterns showed that the crystallinestate of CdS/TiO₂ samples was a mixture of anatase, zinc-blend and wurtzite. SEM micrographs showed that the diameter of CdS particles was 20—50 nm and the diameter of TiO₂ particles was 50—100 nm. The photocatalytic activities of CdS/TiO2 nanopowders were measured by photo-degradation of rhodamine B. When the mole ratio of CdS∶TiO₂ was 1.0, the coupled effect of photocatalytic activities appeared.When the mole ratio of CdS∶TiO2 was 1.5, the coupled effect became the strongest, and the degradation rate of rhodamine B(4 mg•L-1) irradiated by ultraviolet ray for 30 minutes was 74.3%.