核壳结构CdS/TiO2的制备与表征

通过水热法合成分散性良好的CdS纳米颗粒,并采用声化学法在颗粒外包覆TiO2壳层,获得的复合材料具有更好的光催化特性.讨论了水热反应温度保温时间与晶粒尺寸、结晶性之间的关系以及声化学制备过程中反应条件与陈化时间对壳层生长的影响.采用X射线衍射、透射电镜、漫反射光谱、光催化性能测试等手段表征CdS颗粒的尺寸、形貌及CdS/TiO2的结构与光催化特性.结果表明水热过程中,提高反应温度、保温时间有利于提高产物的结晶性.声化学合成CdS/TiO2复合材料过程中,超声作用能促进核壳结构的形成.提高前驱溶液的浓度,在获得CdS/TiO2核壳结构的同时会析出TiO2纳米粒子.在降解甲基橙的实验中,CdS/TiO2材料表现出比单组分材料更好的催化性能.

Synthesis of Core/Shell Type CdS/TiO2

This paper introduced a two-step method for the synthesis of core/shell type nano-composites,which exhibited superior properties over single material,like photoactivity.The core material,cadium sulfide were prepared via a hydrothermal method,using PVP as surfactant to avoid severe aggregation.We obtained high crystalline nanocrystals with dimensions varied from 10 nm to 12 nm,and the nano-particles cohered together to form clusters.We applied a sonochemical route to improve the dispersion properties during the process of hydrolysation of Ti(OC4H9)4 which coated core material with a layer of stable TiO2.By adjusting molar ratio of precursors,morphopology of CdS/TiO2 transferred from CdS embedded in continuous TiO2 matrix to products with obvious core/shell structure,which validated the unique effects of sonochemical method in the synthesis of nano-materials.And from the absorbance spectra of degraded methyl orange,the nanocomposites showed superior photoactivity over single material due to better separation of opposite carriers.