SCI和EI收录∣中国化工学会会刊

中国化学工程学报 ›› 2022, Vol. 45 ›› Issue (5): 78-89.DOI: 10.1016/j.cjche.2021.06.018

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Syngas to ethanol on MoCu(2 1 1) surface: Effect of promoter Mo on C—O bond breaking and C—C bond formation

Lijuan He1,2, Cuimei Zhi3, Lixia Ling4, Riguang Zhang1,2, Baojun Wang1,2   

  1. 1 State Key Laboratory of Clean and Efficient Coal Utilization, Taiyuan University of Technology, Taiyuan 030024, China;
    2 Key Laboratory of Coal Science and Technology (Taiyuan University of Technology), Ministry of Education and Shanxi Province, Taiyuan 030024, China;
    3 College of Chemistry and Bioengineering, Taiyuan University of Science and Technology, Taiyuan 030024, China;
    4 College of Chemistry and Chemical Engineering, Taiyuan University of Technology, Taiyuan 030024, China
  • 收稿日期:2021-02-22 修回日期:2021-06-01 出版日期:2022-05-28 发布日期:2022-06-22
  • 通讯作者: Baojun Wang,E-mail:wangbaojun@tyut.edu.cn
  • 基金资助:
    This work is financially supported by the Key Projects of National Natural Science Foundation of China (21736007) and the National Natural Science Foundation of China (21776193, 21476155).

Syngas to ethanol on MoCu(2 1 1) surface: Effect of promoter Mo on C—O bond breaking and C—C bond formation

Lijuan He1,2, Cuimei Zhi3, Lixia Ling4, Riguang Zhang1,2, Baojun Wang1,2   

  1. 1 State Key Laboratory of Clean and Efficient Coal Utilization, Taiyuan University of Technology, Taiyuan 030024, China;
    2 Key Laboratory of Coal Science and Technology (Taiyuan University of Technology), Ministry of Education and Shanxi Province, Taiyuan 030024, China;
    3 College of Chemistry and Bioengineering, Taiyuan University of Science and Technology, Taiyuan 030024, China;
    4 College of Chemistry and Chemical Engineering, Taiyuan University of Technology, Taiyuan 030024, China
  • Received:2021-02-22 Revised:2021-06-01 Online:2022-05-28 Published:2022-06-22
  • Contact: Baojun Wang,E-mail:wangbaojun@tyut.edu.cn
  • Supported by:
    This work is financially supported by the Key Projects of National Natural Science Foundation of China (21736007) and the National Natural Science Foundation of China (21776193, 21476155).

摘要: The mechanism of syngas to ethanol on MoCu(2 1 1) surface has been researched by density functional theory (DFT) calculation, and the effects of Mo as a promoter on C—O bond breaking and C—C bond formation have been discussed. Calculations show that Cu-Mo atoms constitute the active sites on MoCu(2 1 1) surface after Mo atom being served as a promoter of Cu catalyst. Compared with Cu(2 1 1), MoCu(2 1 1) has two improvements. Firstly, CH3 is the most advantageous monomer on the MoCu(2 1 1) surface, which provides abundant CH3 intermediate for syngas to ethanol. Secondly, the C—C bond is formed mainly by inserting CHO into the abundant CH3, and the generated CH3CHO through multiple steps of hydrogenation to generate C2H5OH. The key of the promoter Mo on the MoCu(2 1 1) surface also has been verified by the analysis of its electronic properties. Differential charge density shows that the massive electron transfer from Mo to Cu, projected density of states (pDOS) shows that the electron transfer from Mo to Cu makes the d-band center of MoCu(2 1 1) nearer to the Fermi level, these indicate that the MoCu(2 1 1) catalytic capacity increased. The addition of Mo in the Cu-based catalyst not only can effectively solve the problem of C—O bond breaking, but also promote C—C bond formation. About the influence of Mo content on C—O bond breaking and C—C bond formation, compared with MoCu(2 1 1), the DFT results and the d-band center of Mo2Cu(2 1 1) show that the increase of Mo content could not promote the synergistic effect of Cu/Mo on the generation of ethanol more effectively.

关键词: Syngas, Ethanol, DFT, Cu catalyst, Promoter Mo

Abstract: The mechanism of syngas to ethanol on MoCu(2 1 1) surface has been researched by density functional theory (DFT) calculation, and the effects of Mo as a promoter on C—O bond breaking and C—C bond formation have been discussed. Calculations show that Cu-Mo atoms constitute the active sites on MoCu(2 1 1) surface after Mo atom being served as a promoter of Cu catalyst. Compared with Cu(2 1 1), MoCu(2 1 1) has two improvements. Firstly, CH3 is the most advantageous monomer on the MoCu(2 1 1) surface, which provides abundant CH3 intermediate for syngas to ethanol. Secondly, the C—C bond is formed mainly by inserting CHO into the abundant CH3, and the generated CH3CHO through multiple steps of hydrogenation to generate C2H5OH. The key of the promoter Mo on the MoCu(2 1 1) surface also has been verified by the analysis of its electronic properties. Differential charge density shows that the massive electron transfer from Mo to Cu, projected density of states (pDOS) shows that the electron transfer from Mo to Cu makes the d-band center of MoCu(2 1 1) nearer to the Fermi level, these indicate that the MoCu(2 1 1) catalytic capacity increased. The addition of Mo in the Cu-based catalyst not only can effectively solve the problem of C—O bond breaking, but also promote C—C bond formation. About the influence of Mo content on C—O bond breaking and C—C bond formation, compared with MoCu(2 1 1), the DFT results and the d-band center of Mo2Cu(2 1 1) show that the increase of Mo content could not promote the synergistic effect of Cu/Mo on the generation of ethanol more effectively.

Key words: Syngas, Ethanol, DFT, Cu catalyst, Promoter Mo