金的化学状态对Au/CoCeO_x催化剂CO氧化性能的影响  

Influence of Chemical States of Au on CO Oxidation over Au/CoCeO_x Catalyst

作　　者：塔娜[1] 张密林[1] 李娟[2] 李华举[2] 申文杰[2] 

机构地区：[1]哈尔滨工程大学材料科学与化学工程学院,黑龙江哈尔滨150001 [2]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》2008年第8期777-782,共6页

摘　　要：以CoCeOx复合氧化物为载体,采用沉积沉淀法制备了负载型的金催化剂,并通过不同温度的预处理控制Au的化学状态.使用粉末X射线衍射、高分辨透射电子显微镜、程序升温还原和X射线光电子能谱对催化剂进行了表征,考察了在室温条件下该系列催化剂的一氧化碳氧化性能.结果表明,Au/CoCeOx催化剂的CO氧化性能与催化剂表面Au+的含量成正比,Au+可能是反应的主要活性物种.添加水汽对反应有一定的促进作用,但由于Au+不能稳定存在,特别是当催化剂表面Au+的含量过高时,在水汽的作用下Au+迅速发生歧化反应,使得催化剂的性能下降.Au/CoCeOx catalysts were prepared by a deposition-precipitation method. Au chemical states were controlled by varying the temperature of pretreatment in an oxygen-containing atmosphere. The catalysts were characterized by powder X-ray diffraction, high-resolution transmission electron microscopy, temperature-programmed reduction, and X-ray photoelectron spectroscopy. The catalytic performance for CO oxidation was investigated at ambient temperature. It was found that the conversion of CO increased with increasing amount of Au^＋ in the catalyst, and thus the cationic gold （Au^＋） was considered the main active species. Addition of water vapor to the feed gas promoted CO conversion to some degree, but the catalytic performance decreased rapidly due to the disproportionation of Au^＋ to Au^3＋ and Au^0, particularly for the catalyst that contained relatively large amounts of Au^＋ species.

关 键 词：氧化钴 氧化铈 复合氧化物 金 化学状态 一氧化碳 低温氧化 

分 类 号：O643.36[理学—物理化学]