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.
The compound semiconductor photocatalyst CdS / TiO_(2) 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 / TiO_(2) respectively. The results indicated that sulfur in the samples existed in the form of CdS covered with a layer of CdSO_(4), 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 TiO_(2). Powder conductivity method was applied to measure the surface state of the samples, and the activities of CdS / TiO_(2) were evaluated with the photocatalytic decoloration of Reactive Brilliant Red X-3B aqueous solution as model. Compared with pure TiO_(2), the surface state energy levels of CdS / TiO_(2) were closer to the conduction band energy level of TiO_(2), 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.
出处
《河南大学学报（自然科学版）》
CAS
2004年第2期28-32,共5页
Journal of Henan University:Natural Science
基金
国家自然科学基金项目(20071010)
关键词
表面态
CdS/TiO2复合半导体
粉末电导法
光催化活性
surface state
compound semiconductor CdS / TiO_(2)
powder conductivity method
photocatalytic activity
