CdS/TiO_2复合纳米管制备和光催化性能的研究

Study on preparation and visible light photocatalytic ability of composited CdS/TiO_2 nanotubes

采用阳极氧化法在纯钛箔上制备TiO2纳米管,再通过连续离子层沉积法在TiO2纳米管上沉积CdS粒子,沉积3层CdS后,进行退火处理,退火后再沉积3层CdS.利用透射电子显微镜(TEM)、X射线衍射(XRD)、X射线光电子能谱(XPS)和拉曼光谱对纳米管的形貌、物相结构和元素价态等特性进行分析.结果表明:经阳极氧化法制备的TiO2纳米管为锐钛矿结构,随后沉积的CdS同时出现了立方相与六方相晶格结构,400℃退火可以显著增加立方相CdS的结晶程度;纳米管中CdS粒子的直径均小于5 nm,CdS粒子由一大一小2个纳米粒子组成,大粒子由退火过程形成.光催化实验表明:经过退火处理的CdS/TiO2复合纳米管的可见光光催化能力约是未退火样品的3倍,说明退火处理可以有效提高TiO2可见光光催化能力.

TiO2 nanotubes were prepared on pure titanium by anodic oxidation method,and CdS was deposited on TiO2 nanotubes by successive ionic layer adsorption and reaction（SILAR） technique.The deposition process was as follows：（1） After 3 layers CdS was deposited,CdS/TiO2 was annealed at 400 ℃ for 30 min,and then more 3-layer was resedimentated（S1）.（2） 6 layers CdS was deposited continuously（S2）.Morphology,phase structure,element valence state and other characteristics of the film were analyzed by using TEM,XRD,XPS and Raman spectroscopy.The results showed that the diameter of deposited CdS was less than 5 nm,CdS nano-particles on sample S1 was composed of a large particle and a small particle.The large particle was formed by the 400 ℃ annealing process.TiO2 prepared by anodic oxidation was anatase structure.The deposited CdS was mainly in the form of ions,which exhibited cubic phase and hexagonal lattice structure of CdS.400 ℃ annealing process could significantly increase the crystallization of cubic phase CdS.Photocatalytic experiments showed that CdS/TiO2 composited structure effectively improve the visible light photocatalysis ability of TiO2,the photocatalytic capacity of sample S1 is three times as high as sample S2.