Au3催化甲酸分解反应机理的密度泛函研究  

A density functional study on the formic acid decomposition mechanism with Au_3 catalyst

作　　者：刘雪云 刘子忠 刘红霞 LIU Xueyun;LIU Zizhong;LIU Hongxia(Chemistry and Environment Science College,Inner Mongolia Normal University,Hohhot 010022,China;Inner Mongolia Key Laboratory of Green Catalysis Hohhot 010022,China)

机构地区：[1]内蒙古师范大学化学与环境科学学院内蒙古自治区绿色催化重点实验室,呼和浩特010022

出　　处：《功能材料》2017年第8期142-150,共9页Journal of Functional Materials

基　　金：内蒙古自然科学基金资助项目(2012MS218)

摘　　要：采用密度泛函理论对trans-HCOOH在有无催化剂条件下的各反应通道进行了研究,在B3LYP/6-311+G(d,p)水平上优化了反应通道上各驻点的几何构型,并计算其振动频率和零点能,通过零点能校正计算了各反应通道的活化能。结果表明,trans-HCOOH分解存在着脱氢与脱水两种途径。在无催化剂条件下,脱氢及脱水路径最佳反应通道速控步骤活化能分别高达319.0和302.2kJ/mol,分子很稳定,很难分解。在Au3催化下,两条路径最佳反应通道速控步活化能明显降低,分别为43.6和82.5kJ/mol,trans-HCOOH更易按照生成CO2和H2的途径来进行分解,Au3催化剂的加入活化了C—H键及O—H键,使速控步骤的活化能显著降低。The density functional theory is performed to investigate each reaction channel of the trans-HCOOH with the condition of the exist/absence of catalyst.Geometry configurations of each stationary points are optimized under the B3LYP/6-311+G(d,p)level.The vibrational frequency and zero-point energy(ZPE)are calculated,and the activation energy of each reaction channelis simulated by ZPE correction.The results indicate that there are two ways in the disintegration process of trans-HCOOH,including dehydrogenation and dehydration,respectively.In the condition of the absence of catalyst,the activation energy in rate controlling step of optimum reaction channel of the two ways are 319.0and 302.2kJ/mol,respectively,which indicate that HCOOH molecular is too stable to disintegrate.After the treatment of Au_3,the significantly reduction of the activation energy can be obvious in the rate controlling step of optimum reaction channel of the two ways,being 43.6and82.5kJ/mol,respectively.This phenomenon can be attributed to the introduction of Au_3,which activate the C—H and O—H bond to reduce the activation energy in rate controlling step.The disintegration ways of transHCOOH prefer to produce the CO_2/H_2 and CO/H_2O,while the former is the main reaction pathway.

关 键 词：Au3催化剂 甲酸 反应机理 密度泛函理论 NBO分析 

分 类 号：O641.12[理学—物理化学]