介孔Al_2O_3负载纳米Au催化剂用于低温催化氧化CO  

Mesoporous Alumina-Supported Nano-Au Catalysts for Carbon Monoxide Oxidation at Low Temperature

作　　者：秦亮生[1] 银董红[1] 刘建福[1] 黎成勇[1] 

机构地区：[1]白沙集团长沙卷烟厂博士后科研工作站,湖南长沙410014

出　　处：《催化学报》2005年第8期714-718,共5页

基　　金：教育部留学回国人员科研启动基金(2003(406)号)资助项目.

摘　　要：用不同模板剂合成了具有较高比表面积和较多表面碱性位的介孔Al2O3载体,并采用均相沉积沉淀法制备了Al2O3负载纳米Au催化剂,对制备的介孔Al2O3载体及相应催化剂采用低温N2吸附法、TEM和XPS等手段进行了表征,考察了载体表面碱性对纳米Au粒子在载体表面的沉积及相应催化剂在CO氧化反应中催化性能的影响.以CO2TPD法测定载体表面碱性,结果表明,介孔氧化铝的表面碱性与其合成过程中所用的模板剂有关.以表面碱性位较丰富的介孔Al2O3为载体制备的催化剂表面Au粒子分布较均匀且粒径(3.1～3.2nm)较小,在CO完全氧化反应中催化活性最高,表明载体表面的碱性位有利于稳定其表面沉积的纳米Au粒子.XPS分析结果表明,催化剂表面的Au主要以Au0金属态形式存在,它在CO氧化反应中表现出较高的催化活性.Three kinds of mesoporous alumina supports denoted as meso-Al2O3-x （x = a, b, c） with different surface basicity were synthesized using P123, cetyltrimethylammonium bromide and chitosan as the templates, respectively. The surface of the mesoporous alumina and the commercial γ-Al2O3 was measured by CO2-TPD. The mesoporous alumina owned more surface basic sites than γ-Al2O3. Au nanoparticles were deposited on meso- Al2O3-x and γ-Al2O3 by homogeneous deposition-precipitation using urea as the precipitation agent. The TEM observation showed that the number of surface basic sites on the supports had obvious effect on the dispersion of the gold particles. The gold particles could be uniformly distributed with average size of 3.1 - 3.2 nm on meso- Al2O3-b and meso-Al2O3-c which had more surface basic sites. The catalytic activity of the supported gold cata- lysts for CO oxidation at low temperature depended on the size of Au particles. The meso-Al2O3-b or meso- Al2O3-c catalysts showed the best catalytic activity at ambient temperature. The XPS results indicated that metallic gold on the reduced catalysts played a great role in the catalytic oxidation of CO.

关 键 词：金 一氧化碳 氧化 介孔氧化铝 负载型催化剂 表面碱性位 

分 类 号：O643.36[理学—物理化学]