γ-Al2O3表面Co物种状态对苯催化燃烧性能的影响研究  

Study of States of Co Species on γ-Al_2O_3 and Activities for Catalytic Combustion of Benzene

作　　者：李志鲲[1] 吕功煊[1] 陈建平[2] 杨宝军[1] 焦天恕[2] 靳志良[1] 邹利鹏[2] 

机构地区：[1]中国科学院兰州化学物理研究所羰基合成与选择氧化国家重点实验室,甘肃兰州730000 [2]中国酒泉卫星发射中心,甘肃兰州732750

出　　处：《分子催化》2008年第1期70-74,共5页Journal of Molecular Catalysis(China)

摘　　要：采用浸渍法在γ-Al2O3载体上制备了不同形态的Co物种,并利用苯的催化燃烧反应考察了各不同物种对苯催化燃烧活性差别.研究结果表明:Co在γ-Al2O3载体表面的分散形态表现出显著的阈值效应.当担载量处于在分散阈值以下时,Co以氧化物形式单层分散于载体表面;当担载量大于分散阈值时,Co团聚为团簇或者多层结晶体形式存在于γ-Al2O3表面.分散阈值效应直接影响着催化剂的催化燃烧活性.焙烧温度对Co在γ-Al2O3表面的存在状态也起着决定性作用.高温焙烧主要导致CoAl2O4尖晶石相生成,而低温焙烧有利于Co3O4物相生成.对于苯催化燃烧反应而言,Co3O4表现出比CoAl2O4高的多的催化活性.The different Co species were prepared on γ-Al2O3 support by wet impregnation method, and the catalytic activities of these Cobalt species were investigated for catalytic combustion of benzene. The results show that obvious effects of dispersion threshold in dispersion of Co on γ-Al2O3. Below the dispersion threshold, Cobalt oxide is dispersed on in monolayer state. Above the dispersion threshold, Co exists in crystals or cluster state on alumina surface. Effect of dispersion threshold affects the activity of catalytic combustion of benzene remarkably. In addition, high temperature treatment resulted in formation of COAl2O4 spinel, which showed lower activity. Co3O4 was identified as the main active phase for catalytic combustion of benzene.

关 键 词：Co/γ-Al2O3 催化燃烧 单层分散 苯 

分 类 号：O643.32[理学—物理化学]