阶梯Cu(221)面催化还原CO制甲醇反应机理及其电子效应的理论研究  

Theoretical study on reaction mechanisms and electron effects of CO catalytic reduction to methanol on stepped Cu(221)surface

作　　者：刘婷婷[1] 白慧 白冰[1] 徐慧凯 刘勇军[1] 黄伟[1] LIU Tingting;BAI Hui;BAI Bing;XU Huikai;LIU Yongjun;HUANG Wei(State Key Laboratory of Clean and Efficient Coal Utilization,Taiyuan University of Technology,Taiyuan 030024,Shanxi,China)

机构地区：[1]太原理工大学省部共建煤基能源清洁高效利用国家重点实验室,山西太原030024

出　　处：《低碳化学与化工》2025年第4期29-37,54,共10页Low-Carbon Chemistry and Chemical Engineering

基　　金：山西省科技合作交流项目(202304041101027);山西省基础研究计划(202103021224044,202203021212264)。

摘　　要：Cu基催化剂是一种高效还原CO制甲醇的绿色催化剂,其不同晶面的甲醇合成性能不同,因此明确其反应机理对催化剂设计及开发具有重要意义。目前稳定性最高的阶梯Cu(221)面的CO加氢制甲醇反应机理尚不明确。基于密度泛函理论,通过对比阶梯Cu(221)面CO加氢制甲醇过程中相关基元反应的活化能和反应热,明确了甲醇合成的最优路径。系统对比了活性Cu位点配位数较高的露台Cu(100)、Cu(111)面与活性Cu位点配位数较低的阶梯Cu(110)、Cu(211)、Cu(611)和Cu(221)面上CO加氢制甲醇最优反应路径中的决速步能垒(Cu(221):0.77 eV、Cu(611):0.88 eV、Cu(211):0.99 eV、Cu(110):1.04 eV、Cu(100):1.05 eV和Cu(111):1.21 eV),证实了阶梯Cu(221)面具有最优的甲醇合成性能。结合Bader电荷、态密度、差分电荷密度和晶体轨道哈密顿布居分析,从微观电子层面进一步揭示了CO活化转化过程,发现电负性更强的台阶边缘位点与关键物种之间的强静电相互作用是阶梯Cu(221)面具有较高催化活性的本质原因。Cu based catalysts are one of efficient green catalysts for catalytic CO reduction to methanol,and different crystal surfaces of Cu based catalysts exhibit different catalytic performances.Therefore,clarifying the reaction mechanisms on different surfaces is crucial for design and development of catalysts.At present,the reaction mechanisms of stepped Cu(221)surface with the highest stability for CO hydrogenation to methanol are not clear.Based on density functional theory,the optimal pathway for methanol synthesis on the stepped Cu(221)surface was determined via compared activation energies and reaction heats of related elementary reactions.The rate determining step energy barriers during the optimal pathways of methanol synthesis over the terrace Cu(100)and Cu(111)surfaces with higher coordination numbers and stepped Cu(110),Cu(211),Cu(611)and Cu(221)surfaces with lower coordination numbers of Cu active sites were systematically compared(Cu(221):0.77 eV,Cu(611):0.88 eV,Cu(211):0.99 eV,Cu(110):1.04 eV,Cu(100):1.05 eV and Cu(111):1.21 eV).It is confirmed that stepped Cu(221)surface has the best methanol synthesis performance.Combined with Bader charge,density of state,differential charge density and Crystal Orbital Hamiltonian Popution,the CO activation and conversion process was further revealed at the microscopic electronic level.It is found that the strong electrostatic interaction between the step edge site with stronger electronegativity and key species is the essential reason for the high catalytic activity of the stepped Cu(221)surface.

关 键 词：密度泛函理论 阶梯Cu(221)面 CO活化 甲醇 反应机理 

分 类 号：TQ072[化学工程]