A density functional theory study of methane activation on MgO supported Ni_(9)M_(1) cluster:role of M on C-H activation  

作　　者：Juntian Niu Haiyu Liu Yan Jin Baoguo Fan Wenjie Qi Jingyu Ran 

机构地区：[1]College of Electrical and Power Engineering,Taiyuan University of Technology,Taiyuan 030024,China [2]Key Laboratory of Advanced Manufacturing Technology for Automobile Parts,Ministry of Education,Chongqing University of Technology,Chongqing 400050,China [3]Key Laboratory of Low-grade Energy Utilization Technologies and Systems,Ministry of Education,Chongqing University,Chongqing 400044,China

出　　处：《Frontiers of Chemical Science and Engineering》2022年第10期1485-1492,共8页化学科学与工程前沿（英文版）

基　　金：supported by the National Natural Science Foundation of China(Grant No.52106179);the Fundamental Research Program of Shanxi Province,China(Grant No.20210302124017);the Natural Science Foundation of Chongqing,China(Grant No.cstc2020jcyj-msxmX0454);the Scientific and Technological Activities for Overseas Students of Shanxi Province,China(Grant No.20200016).

摘　　要：Methane activation is a pivotal step in the application of natural gas converting into high-value added chemicals via methane steam/dry reforming reactions.Ni element was found to be the most widely used catalyst.In present work,methane activation on MgO supported Ni–M(M=Fe,Co,Cu,Pd,Pt)cluster was explored through detailed density functional theory calculations,compared to pure Ni cluster.CH_(4)adsorption on Cu promoted Ni cluster requires overcoming an energy of 0.07 eV,indicating that it is slightly endothermic and unfavored to occur,while the adsorption energies of other promoters M(M=Fe,Co,Pd and Pt)are all higher than that of pure Ni cluster.The role of M on the first C–H bond cleavage of CH_(4)was investigated.Doping elements of the same period in Ni cluster,such as Fe,Co and Cu,for C–H bond activation follows the trend of the decrease of metal atom radius.As a result,Ni–Fe shows the best ability for C–H bond cleavage.In addition,doping the elements of the same family,like Pd and Pt,for CH_(4)activation is according to the increase of metal atom radius.Consequently,C–H bond activation demands a lower energy barrier on Ni–Pt cluster.To illustrate the adsorptive dissociation behaviors of CH_(4)at different Ni–M clusters,the Mulliken atomic charge was analyzed.In general,the electron gain of CH_(4)binding at different Ni–M clusters follows the sequence of Ni–Cu(–0.02 e)<Ni(–0.04 e)<Ni–Pd(–0.08 e)<Ni–Pt(–0.09 e)<Ni–Co(–0.10 e)<Ni–Fe(–0.12 e),and the binding strength between catalysts and CH_(4)raises with the CH_(4)electron gain increasing.This work provides insights into understanding the role of promoter metal M on thermal-catalytic activation of CH_(4)over Ni/MgO catalysts,and is useful to interpret the reaction at an atomic scale.

关 键 词：CH_(4) dissociation Ni-M C-H bond activation charge transfer 

分 类 号：O64[理学—物理化学]