Au/Fe-O催化剂活性组分在CO催化氧化反应中的存在状态  

The State of Active Au Species in Au/Fe-O Catalyst during CO Catalytic Oxidation

作　　者：李常艳[1] 沈岳年[1] 胡瑞生[1] 贾美林[2] 盛世善 

机构地区：[1]内蒙古大学化学化工学院,内蒙古呼和浩特010021 [2]内蒙古师范大学化学与环境科学学院,内蒙古呼和浩特010022 [3]中国科学院大连化学物理研究所催化基础国家重点实验室,辽宁大连116023

出　　处：《催化学报》2006年第3期259-262,共4页

基　　金：国家自然科学基金(20263001);内蒙古大学青年基金(ND412)资助项目

摘　　要：采用传统的共沉淀法制备了Au/Fe-O催化剂,运用X射线衍射、X射线光电子能谱和透射电镜技术对其进行了表征,考察了它们对CO氧化反应的催化活性. 结果表明,虽然负载在Fe-O载体上的金晶粒较大（10～15 nm）, 但由于采用了共沉淀法制备催化剂,金和载体可紧密接触并产生较强的相互作用. 催化剂中Au 5d轨道上的电子流入Fe 3d轨道,使Au 5d轨道处于非全充盈状态,金呈Au^δ＋状态（0＜δ＜1）, 这是该催化剂具有较高催化活性的根本原因. CO催化氧化反应测试结果表明,当金含量较高时, CO的转化率在室温下就能达到100%.A series of Au/Fe-O catalysts have been prepared by a co-precipitation method from a mixture of HAuCl4·4H2O and Fe（NO3）3-9H2O. These catalysts exhibit good catalytic activity for CO oxidation. The most active catalyst has 100 % CO conversion at room temperature. The calcined catalysts were characterized by X-ray diffraction, X-ray photoelectron spectroscopy （XPS）, and transmission electron microscopy （TEM）. TEM observations reveal a homogenous distribution of gold particles between 10 and 15 nm on the iron oxide support. XPS results show that partially oxidized gold species exist in these samples. The difference in binding energies of Au 4f between these samples and bulk gold can be interpreted as that the Au 5d electrons partially flow into the Fe 3d orbit to some extent. So the attraction of nucleus in gold atoms is enhanced, resulting in the increase in the binding energies of Au 4f. This fact reflects that there exists an interaction between the gold nanoparticles and the support. For the CO oxidation on the 10-15 nm Au/Fe-O catalyst, the interaction between nanogold particles and iron oxide has more important influence on catalyst performance than the particle size of nanogold.

关 键 词：纳米金 氧化铁 负载型催化剂 金的存在状态 一氧化碳 催化氧化 

分 类 号：O643.36[理学—物理化学]