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CdS/TiO2复合半导体的表面态及光催化性能
Study on Surface State and Photocatalytic Property of the Compound Semiconductor CdS / TiO2
【摘要】 采用浸渍法制备了CdS/TiO2复合半导体光催化剂.使用XPS和UV Vis扩散—反射谱对样品的表面组成及光吸收特性进行了分析.结果表明,样品中的硫主要以CdS形式存在,其外层包裹了一层CdSO4;由于在TiO2表面修饰了CdS,使样品的吸收带边由400nm(3.1eV)红移至530nm(2.3eV).采用粉末电导装置对CdS/TiO2薄膜的表面态能级进行了测试,并以活性艳红X 3B水溶液的光催化脱色为指标反应,对CdS/TiO2的活性进行了评价.与单一TiO2相比,CdS/TiO2的表面态更靠近TiO2的导带,有利于电子在表面的捕获,从而提高了样品中自由电荷的浓度,加速了活性艳红X 3B水溶液的光催化脱色反应.
【Abstract】 The compound semiconductor photocatalyst CdS / TiO2 was prepared by dipping method. XPS and UV-Vis diffusing-reflecting spectra were applied to analyze the surface composite and the optical properties of as-prepared CdS / TiO2 respectively. The results indicated that sulfur in the samples existed in the form of CdS covered with a layer of CdSO4, and that the threshold of the samples shifted from 400 nm (3.2 eV) to 530 nm (2.3 eV) because of the modification of CdS on the surface of TiO2. Powder conductivity method was applied to measure the surface state of the samples, and the activities of CdS / TiO2 were evaluated with the photocatalytic decoloration of Reactive Brilliant Red X-3B aqueous solution as model. Compared with pure TiO2, the surface state energy levels of CdS / TiO2 were closer to the conduction band energy level of TiO2, which means that more excited electrons were trapped at the surface of the sample, and finally resulted in the promotion of the photocatalytic decoloring rate of Reactive Brilliant Red X-3B aqueous solution.
【Key words】 surface state; compound semiconductor CdS / TiO2; powder conductivity method; photocatalytic activity;
- 【文献出处】 河南大学学报(自然科学版) ,Journal of Henan University (Natural Science) , 编辑部邮箱 ,2004年02期
- 【分类号】TN304
- 【被引频次】76
- 【下载频次】632