镍基上羟基活化催化CH4-CO2重整的理论计算

摘要

The mechanism of methane's hydroxyl-activate-reforming with carbon dioxide on nickel has been investiga ted by DFT, MP2/6-311 + G(2d,p) method, Comparison of the reforming reaction mechanism and explore the vari ous channels. The results have showed that the reforming reaction divided into 22 steps, the activation enthalpy of important five steps were: 44. 718,201.353,265. 713,104.603,61.739 and 99. 331 kJ ? mol-1. The rate-controlling step was the generation of hydroxyl process, and the most decomposition of methane was took off one hydrogen at om, CH3Ni has more high activity. There are two ways in the reaction between hydroxyl and CH3 Ni. The product is CH2OH , which could cleaved into formaldehyde.%采用DFT(B3LYP)结合二级微扰MP2/6-311+G(2d,p)方法计算镍基催化剂上羟基活化催化CH4-CO2 重整制合成气的反应机理,比较并探究了重整反应机理中的各种通道.计算结果表明,重整反应包含22步,关键反应式1-1,2,3,4-1,4-2,6-4的正反应活化能分别为44.718,201.353,265.713,104.603,61.739和99.331kJ·mo1-1.重整的速控步是式3表示的羟基的产生过程,甲烷的分解以脱1个H为主,基团CH3Ni具有较高的活性,可以通过2种方式与羟基反应,生成CH2OH基团继而裂解成甲醛.