高分子模板对CdS量子点制备及其光催化性能的影响  

Effect of Polymer Templates on the Preparation and Photocatalytic Activity of CdS Quantum Dots

作　　者：丛日敏[1,2] 罗运军[2] 于怀清[1] 

机构地区：[1]北京理工大学材料科学与工程学院,北京100081 [2]山东理工大学材料科学与工程学院,淄博255049

出　　处：《化学学报》2010年第19期1971-1976,共6页Acta Chimica Sinica

基　　金：北京理工大学基础研究基金(No.BIT-UBF-200504E4203);山东理工大学科技博士基金(No.4041-406038)资助项目

摘　　要：分别以球形聚酰胺-胺(PAMAM)树形分子和线形聚乙烯吡咯烷酮(PVP)两种结构不同的高分子为模板,原位制备了分散良好的CdS量子点(CdSQDs),并以甲基橙为降解对象,研究了高分子模板结构对CdS量子点的制备和光催化性能的影响.结果表明,以PAMAM树形分子为模板制备的CdS量子点(CdSQDs/PAMAM)比以PVP为模板制备的CdS量子点(CdSQDs/PVP)的尺寸分布更窄,激子吸收峰更明显,光致发光(PL)强度更高;并且在量子点尺寸接近的情况下,CdSQDs/PAMAM的催化效率明显高于CdSQDs/PVP.这是由于PAMAM树形分子独特的结构有利于生成尺寸均匀的CdS量子点,且不易钝化量子点表面的活性位点;而线性的PVP分子量分布较宽,使制备的量子点的尺寸分布较宽,且PVP分子链缠绕在CdS量子点表面,钝化了部分活性位点,降低催化效率.此外,CdSQDs/PAMAM的催化能力随粒径减小而增大.Well dispersed CdS quantum dots （QDs） were in-situ prepared using poly（amidoamine） （PAMAM） dendrimers and poly（N-vinyl-2-pyrrolidone） （PVP） as templates respectively, and effects of both polymer templates on the preparation and photocatalytic properties of CdS QDs were studied through methyl orange degradation. The results show that the size distribution of PAMAM dendrimers-stabilized CdS QDs （CdS QDs/PAMAM） is much narrower than that of PVP stabilized CdS QDs （CdS QDs/PVP）, and the exci-ton absorption peak and PL intensity of the former are much stronger. At the similar size, the photocatalytic efficiency of CdS QDs/PAMAM is much higher than that of CdS QDs/PVP. Differences in molecular struc-ture between PAMAM and PVP are the major influence factors to the above contrast. PAMAM dendrimers are excellent templates for preparing CdS QDs with controlled size and narrow size-distribution. And most of the catalytic active sites in the surface of CdS QDs are not passivated by PAMAM dendrimer branches, which act as porous channels for methyl orange. However, many catalytic active sites in the surface of CdS QDs/PVP are passivated by the long twining PVP chains, which decrease the photocatalytic efficiency of CdS QDs/PVP. Besides, the narrower size-distribution of CdS QDs/PAMAM contributes to their high photocatalytic efficiency to some degree. In addition, the photocatalytic efficiency of CdS QDs increases when the size becomes smaller because of the larger specific surface area, stronger quantum confinement effect, and higher photo-production electron and hole energy of smaller QDs.

关 键 词：CDS量子点 PAMAM树形分子 聚乙烯吡咯烷酮 光催化 甲基橙 

分 类 号：O643.36[理学—物理化学]