Au/CeO_2/SiO_2催化CO低温氧化反应过程中CeO_2的作用(英文)  

Role of CeO_2 in Three-Component Au/CeO_2/SiO_2 Composite Catalyst for Low-Temperature CO Oxidation

作　　者：张慧丽[1] 任丽会[1] 陆安慧[1] 李文翠[1] 

机构地区：[1]大连理工大学化工与环境生命学部化工学院精细化工国家重点实验室,辽宁大连116024

出　　处：《催化学报》2012年第7期1125-1132,共8页

基　　金：国家自然科学基金(20973031);教育部新世纪优秀人才支持计划(NCET-08-0075);国家教育部博士点基金(20100041110017)~~

摘　　要：采用具有分等级孔道结构的SiO2(HMS)为载体,通过润湿浸渍引入少量CeO2,经焙烧得到CeO2/HMS复合载体,然后采用沉积沉淀法负载上Au纳米粒子,得到Au/CeO2/HMS三元复合催化剂.通过X射线衍射、程序升温还原和原位红外光谱等手段表征了催化剂的结构.结果表明,CeO2的存在可控制Au颗粒的沉积并稳定载体上的纳米Au颗粒.Au/CeO2/HMS上CO低温氧化反应完全转化温度为60oC.高度分散的Au0可以活化CO,CeO2颗粒则可以提供反应需要的氧.稳定性测试结果显示,反应48h催化剂活性维持不变.Hierarchical composite nanostructure composed of Au, CeO2, and SiO2 was fabricated by sequentially depositing ceria nanoparticles through impregnation and calcination, and then gold nanoparticles through a deposition-precipitation method on hierarchical monolithic silica （HMS） with multi-length scale pore structure. The Au/CeO2/HMS composite nanostructure was characterized by X-ray diffraction, temperature-programmed reduction, and diffuse reflectance infrared Fourier transform spectroscopy. The results indicate that the presence of ceria had a significant effect on targeted deposition and stabilization of small metallic gold nanoparticles on the support. The temperature for complete conversion of CO to CO2 over Au/CeO2/HMS is ca. 60 oC at a space velocity of 80000 ml/（g·h）. The highly dispersed metallic gold nanoparticles can activate CO and the small ceria nanoparticles supply oxygen in the reaction. The catalytic activity remains considerably stable during 48 h stability testing. The interaction between gold and ceria contributed greatly to CO oxidation and the presence of silica improved the stability of the gold catalyst.

关 键 词：二氧化硅 一氧化碳氧化 金 二氧化铈 稳定性 

分 类 号：O643.36[理学—物理化学]