碱土金属氧化物阳离子~2MO^+(M=Ca,Sr,Ba)参与N_2O与CO反应的理论研究  

Theoretical Study for the Reduction of N_2O with CO Mediated by alkaline-earth metal oxide cations ~2MO^+(M=Ca,Sr,Ba)

作　　者：张建辉[1,2] 冷艳丽[1] 王永成[2] 

机构地区：[1]兰州资源环境职业技术学院冶金工程系,兰州730021 [2]西北师范大学化学化工学院,兰州730070

出　　处：《原子与分子物理学报》2013年第4期525-530,共6页Journal of Atomic and Molecular Physics

摘　　要：本文采用UB3LYP/6-311G(2d)+SDD//CCSD(T)/6-311+G(2d)+SDD方法,计算研究了气相中碱土金属氧化物阳离子2 MO+(M=Ca,Sr,Ba)参与N2O(X1∑+)+CO(X1∑+)→N2(X1∑g+)+CO2(X1∑g+)的反应机理.通过计算亲氧性得到在三种氧化物阳离子中只有2 CaO+从N2O得到O原子并传递给CO的过程是热力学允许的.碱土金属氧化物阳离子2 MO+参与主题反应的机理通过以下两种方式进行,其一为2 MO+从N2O获取O原子生成2 MO2+,进而向CO提供O原子得到2 MO+和CO2,该过程为催化反应机理;其二为2 MO+先与N2O复合生成中间体IM1,之后IM1继续与CO复合生成中间体IM2′,经过一系列反应过程最终生成2 MO+,N2和CO2.通过对两种反应过程的热力学性质和动力学因素分析得到,2 MO+(M=Ca,Sr,Ba)参与反应N2O(X1∑+)+CO(X1∑+)→N2(X1∑g+)+CO2(X1∑g+)的机理为后一路径,所得结果与实验观测相符.The reaction mechanism of the reaction N2O（1∑＋） ＋ CO（1∑＋） → N2（1∑＋g） ＋ CO2（1∑＋g） mediated by alkaline-earth metal oxide cations 2MO＋（M=Ca,Sr,Ba） have been investigated by using the UB3LYP and CCSD（T） levels of theory.The O-atom affinities（OA） testified that only the 2CaO＋ can capture O from N2O and transfer O to CO is thermodynamically allowed in three ions.The processes can be expressed as channels 1 and 2 for the reaction of N2O and CO mediated by 2MO＋（M=Ca,Sr,Ba）.For the former,the main reaction processes in a two-step manner to products,the 2MO＋,as a catalyzer,transports an oxygen atom from N2O to CO.For the latter,firstly,the N2O interact with the 2MO＋ to form IM1,then IM1 interact with the CO to form IM2′,along the reaction pathway the intermediate species convert into products 2MO＋,N2 and CO2.From above results,the following conclusion was drawn.The channel 2 is kinetically and thermodynamically feasible.Our calculated results show the title reactions are accord with the experiment.

关 键 词：2MO+(M=Ca+ Sr+ Ba+) N2O和CO 反应机理 

分 类 号：O643.12[理学—物理化学]