p-n复合半导体CoO/CdS敏化TiO2可见光催化分解水制氢

项目名称： p-n复合半导体CoO/CdS敏化TiO2可见光催化分解水制氢

项目编号： No.50876047

项目类型： 面上项目

立项/批准年度： 2009

项目学科： 金属学与金属工艺

项目作者： 刘福生

作者单位： 南京林业大学

项目金额： 35万元

中文摘要： 以钛酸四丁酯、氯化镉、硫化钠和醋酸钴为前驱体，制备了p-CoO/n-CdS和p-CoO/n-CdS/TiO2光催化剂。用XRD、SEM、TEM和BET对制备产物进行了结构表征，用UV-Vis DRS进行了光吸收性能研究。用可见光催化分解水制氢和降解甲基橙进行光催化性能研究。探讨了p-CoO/n-CdS和p-CoO/n-CdS/TiO2的组成与其光催化性能的关系，优化了光催化分解水制氢反应和光催化降解反应的工艺条件。结果表明，宽带隙半导体TiO2和窄带隙半导体CdS复合，既可有效吸收可见光，又能有效提高电子-空穴对的分离效率，再与p型半导体CoO复合，可以通过形成p-n结，进一步提高电子-空穴对的分离效率，显著提高光催化性能。光催化活性大小的顺序是CoO/CdS/TiO2>CoO/CdS>CdS。 CdS的光腐蚀研究结果表明，CoO和CdS接触表面形成的p-n结使光生空穴由CdS向CoO迁移，TiO2与CdS复合使得光生电子由CdS向TiO2迁移，两者都有利于降低CdS表面的光腐蚀反应，研究结果表明，光腐蚀速率顺序为：CdS>CoO/CdS>CoO/CdS/TiO2。

中文关键词： p-n复合半导体；CoO/CdS；TiO2；光催化；制氢

英文摘要： In this paper, p-n type composite semiconductor photocatalyst p-CoO/n-CdS and p-CoO/n-CdS/TiO2 were prepared by tetrabutyl titanate, cadmium chloride, sodium sulphide and cobalt acetate. The structural and optical properties of p-CoO/n-CdS and p-CoO/n-CdS/TiO2 were characterized by XRD, SEM, TEM, BET and UV-Vis DRS. The photocatalytic activities of the photocatalysts were evaluated by photocatalytic hydrogen production by water splitting and photocatalytic decomposition of methyl orange irradiated with visible light. The relation between the composition of p-CoO/n-CdS and p-CoO/n-CdS/TiO2 and the photocatalytic activity was investigated to obtain the optimal conditions. The results showed that wide band-gap semiconductor TiO2 coupled with narrow band-gap semiconductor CdS could not only generate electron-hole pairs under visible light irradiation, but also effectively separate photogenerated electrons and holes. When p-type CoO and n-type CdS/TiO2 integrated, a p-n junction would be formed between p-CoO and n-CdS, which could further separate electron-hole pairs to avoid recombine and enhance the photocatalytic activity. So, the order of photocatalytic activity was CoO/CdS/TiO2>CoO/CdS>CdS. The the leakage of cadmium by photocorrosion in CoO/CdS and CoO/CdS/TiO2 was also discussed. The results showed that photogenerated holes would flow from CdS surface to CoO surface by p-n junction formed between p-CoO and n-CdS.And photogenerated electrons would move from CdS surface to TiO2 surface when TiO2 coupled with CdS.All these reduced the possibility of reaction with photogenerated holes and CdS on CdS surface.Therefore, the order of preventing the leakage of cadmium is CoO/CdS/TiO2>CoO/CdS>CdS.

英文关键词： P-n coupled semiconductor; CoO/CdS; TiO2; Photocatalysis; Hydrogen production