热处理对Cu/Ag-OMS-2催化剂中铜物种表面状态的影响  

Effects of calcination treatment on surface state of copper species in Cu / Ag-OMS-2 catalysts

作　　者：王锐[1,2] 余甜雨 曾琴[1,2] 李艳[1,2] 刘慧[1,2] 邓尉[1,2] 杨小俊[1,2] 

机构地区：[1]绿色化工过程教育部重点实验室(武汉工程大学),湖北武汉430074 [2]武汉工程大学化工与制药学院,湖北武汉430074

出　　处：《武汉工程大学学报》2015年第9期18-23,共6页Journal of Wuhan Institute of Technology

基　　金：湖北省自然科学基金(2013CFB322);湖北省教育厅青年人才项目(Q20131503);绿色化工过程教育部重点实验室开放基金项目(GCP201301);武汉工程大学青年基金项目(10112061)

摘　　要：对Cu/Ag-OMS-2(OMS-2为锰氧八面体分子筛)催化剂中铜物种在热处理过程中的分散情况和存在形式进行了研究,通过X射线衍射、扫描电子显微镜表征手段分别考察了焙烧温度、焙烧时间和活性组分负载量不同时催化剂中铜物种的表面状态,并分析了铜物种表面状态对催化氧化羰基化合成碳酸二甲酯反应的影响.结果表明,在热处理过程中,铜物种以片状形式均匀排列堆积,有利于反应物的吸附,有利于催化剂活性的提升;活性组分主要以氯化铜(Cu Cl)形式存在,受热部分分解为含有Cu+和Cu2+的铜氧化物6Cu O·Cu2O,两种不同价态的铜物种的存在促进反应物的解离吸附,有利于提升催化活性.较适宜的催化剂热处理条件为:Cu Cl的负载量为25%,焙烧温度为500℃,焙烧时间为5 h,催化合成碳酸二甲酯的收率最高可达85%.The dispersion state and the existence form of copper species in Cu / Ag-OMS-2 catalysts were investigated. The surface states of copper species at different calcination temperatures, different calcination times and different Cu Cl loadings were studied by X-ray diffraction and scanning electron microscope. The effects of surface state of copper species on catalytic performance of Cu / Ag-OMS-2 in oxidative carbonylation of methanol were also determined. The results show that the copper species existed in thin slice form and disperse well on the catalyst surface after calcination treatment,which is beneficial to adsorption of the reactants and catalytic activities; the active species exist mainly in the form of Cu Cl, and partly decompose into 6Cu O·Cu2O including Cu＋and Cu2＋species; the mixed valence of copper species is advantageous to good catalytic performance. The optimal preparation condition of Cu / Ag-OMS-2 catalysts is calcined at 500 ℃ for 5 h and the Cu Cl loading of 25%, and the yield of dimethyl carbonate for corresponding catalyst reaches 85%.

关 键 词：碳酸二甲酯 甲醇 氧化羰基化 锰氧八面体分子筛 铜催化剂 

分 类 号：TQ225.52[化学工程—有机化工]