Mn-CaO催化剂上甲烷-二氧化碳共活化制C_2烃研究II.催化剂表征及反应机理研究  

Selective Conversion of CH_4 and CO_2 to C_2 Hydrocarbons over Mn-CaO catalysts II.Catalysts Characterization and Mechanism Deduce

作　　者：蔡迎春[1] 丑凌军[1] 张兵[1] 赵军[1] 李树本[1] 

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

出　　处：《分子催化》2005年第5期327-331,共5页Journal of Molecular Catalysis(China)

基　　金："甲烷及液化石油气选择氧化制高级烃"(Grant20373081)

摘　　要：在Mn-CaO催化剂开展了一系列的表征,包括XRD,XPS,CO2-TPD.结合催化剂评价、表征结果,对催化反应机理进行了推测,指出Mn组分与催化剂的活性相关联而Ca组分的主要作用是提供吸附型的CO2(a)*,反应过程中形成的Mn3+/Mn2+离子对在CO2和CH4的活化过程中扮演了重要角色.XRD, XPS, CO2-TPD were employed for characterization of Mn-CaO catalysts. Combine the results of catalyst characterization and catalyst evaluation, the following conclusions were drawn： Mn component is the active phase of Mn-CaO catalysts while the role of the Ca component is to provide adsorbed CO2; The possible mechanism for CH4 and CO2 to produce C2 hydrocarbons over Mn-CaO catalysts were deduced as follows： CO2 may first be adsorbed on CaO sites and then may be dissociated at high reaction temperature to produce CO2（a）^＊, CO2（a）^＊ was activated by Mn^2＋, CO and O^- was formed, the surface reactive oxygen species O^- abstract hydrogen from methane to give methyl radicals, which in turn are converted to C2 hydrocarbons. At the same time, Mn^3＋ was reduced to Mn^2＋.

关 键 词：Mn-CaO 甲烷 二氧化碳 C2烃 Mn^3+/Mn^2+ 机理研究 

分 类 号：O643.32[理学—物理化学]