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First-Principles Microkinetic Study of Methanol Synthesis on Cu(221) and ZnCu(221) Surfaces
Sha-sha Wang,Min-zhen Jian,Hai-yan Su,Wei-xue Li*
Author NameAffiliationE-mail
Sha-sha Wang State Key Laboratory of Catalysis, State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 110623, China;University of Chinese Academy of Sciences, Beijing 100049, China  
Min-zhen Jian School of Chemistry and Materials Science, Hefei National Laboratory for Physical Sciences at Microscales, University of Science and Technology of China, Hefei 230026, China  
Hai-yan Su State Key Laboratory of Catalysis, State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 110623, China  
Wei-xue Li* State Key Laboratory of Catalysis, State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 110623, China;School of Chemistry and Materials Science, Hefei National Laboratory for Physical Sciences at Microscales, University of Science and Technology of China, Hefei 230026, China wxli70@ustc.edu.cn 
Abstract:
First-principle based microkinetic simulations are performed to investigate methanol synthesis from CO and CO2 on Cu(221) and CuZn(221) surfaces. It is found that regardless of surface structure, the carbon consumption rate follows the order:CO hydrogenation > CO/CO2 hydrogenation > CO2 hydrogenation. The superior CO hydrogenation activity mainly arises from the lower barriers of elementary reactions than CO2 hydrogenation. Compared to Cu(221), the introduction of Zn greatly lowers the activity of methanol synthesis, in particularly for CO hydrogenation. For a mixed CO/CO2 hydrogenation, CO acts as the carbon source on Cu(221) while both CO and CO2 contribute to carbon conversion on CuZn(221). The degree of rate control studies show that the key steps that determine the reaction activity of CO/CO2 hydrogenation are HCO and HCOO hydrogenation on Cu(221), instead of HCOOH hydrogenation on CuZn(221). The present work highlights the effect of the Zn doping and feed gas composition on methanol synthesis.
Key words:  Methanol synthesis  Cu(221)  CuZn(221)  Density functional theory  Microkinetic simulations
FundProject:This work was supported by the National Key R&D Program of China (No.2017YFB0602205, No.2017YFA0204800), the National Natural Science Foundation of China (No.91645202, No.91421315), the Chinese Academy of Sciences (No.QYZDJ-SSWSLH054, No.XDA09030101).
Cu(221)和CuZn(221)表面甲醇合成的基于第一性原理微观动力学的理论研究
王莎莎,简敏珍,苏海燕,李微雪*
摘要:
本文基于第一性原理的微观动力学模拟方法,对Cu(221)和CuZn(221)上一氧化碳和二氧化碳加氢到甲醇进行了系统的理论计算研究.研究发现,碳转化率在两个表面上均表现出相同的活性顺序:CO加氢活性 > CO/CO2混合加氢活性 > CO2加氢活性.CO的高转化活性源于其基元反应能垒低于CO2甲醇合成的基元反应能垒.相比于Cu(221)表面,Zn的掺杂显著降低了甲醇合成活性,尤其是CO加氢的活性.对于CO和CO2共存的情况,研究发现CO是Cu(221)甲醇合成的主要碳源,而CuZn(221)上的碳源则由CO和CO2共同提供.反应速控度分析表明,CO/CO2混合气甲醇合成的速控步在Cu(221)表面是HCO、HCOO的加氢,而在CuZn(221)表面速控步则是HCOOH的加氢.这些研究结果表明铜基催化剂上Zn的表面合金效应、以及合成气组分对甲醇合成的活性和反应通道具有重要的影响.
关键词:  甲醇合成  铜锌催化剂  微观动力学  第一性原理
DOI:10.1063/1674-0068/31/cjcp1803038
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