SCI和EI收录∣中国化工学会会刊

中国化学工程学报 ›› 2022, Vol. 50 ›› Issue (10): 254-263.DOI: 10.1016/j.cjche.2022.06.023

• Catalysis, Kinetics and Reaction Engineering • 上一篇    下一篇

Concentration fluctuation caused by reaction-diffusion coupling near catalytic active sites

Haolei Zhang1,2, Mingcan Zhao1, Yanping Li1, Chengxiang Li1,3, Wei Ge1,2,4   

  1. 1 State Key Laboratory of Multiphase Complex Systems, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China;
    2 School of Chemical Engineering, University of the Chinese Academy of Sciences, Beijing 100049, China;
    3 Dalian National Laboratory for Clean Energy, Chinese Academy of Sciences, Dalian, Liaoning 116023, China;
    4 Innovation Academy for Green Manufacture, Chinese Academy of Sciences, Beijing 100049, China
  • 收稿日期:2022-02-27 修回日期:2022-06-02 出版日期:2022-10-28 发布日期:2023-01-04
  • 通讯作者: Chengxiang Li,E-mail:licx@ipe.ac.cn;Wei Ge,E-mail:wge@ipe.ac.cn
  • 基金资助:
    This work was supported by the National Natural Science Foundation of China (92034302 and 22178347), the Dalian National Laboratory for Clean Energy (DNL) Cooperation Fund, the Chinese Academy of Sciences (DNL201905), the "Transformational Technologies for Clean Energy and Demonstration", Strategic Priority Research Program of the Chinese Academy of Sciences (XDA21030700), the National Science and Technology Major Project (2017-I-0004-0005).

Concentration fluctuation caused by reaction-diffusion coupling near catalytic active sites

Haolei Zhang1,2, Mingcan Zhao1, Yanping Li1, Chengxiang Li1,3, Wei Ge1,2,4   

  1. 1 State Key Laboratory of Multiphase Complex Systems, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China;
    2 School of Chemical Engineering, University of the Chinese Academy of Sciences, Beijing 100049, China;
    3 Dalian National Laboratory for Clean Energy, Chinese Academy of Sciences, Dalian, Liaoning 116023, China;
    4 Innovation Academy for Green Manufacture, Chinese Academy of Sciences, Beijing 100049, China
  • Received:2022-02-27 Revised:2022-06-02 Online:2022-10-28 Published:2023-01-04
  • Contact: Chengxiang Li,E-mail:licx@ipe.ac.cn;Wei Ge,E-mail:wge@ipe.ac.cn
  • Supported by:
    This work was supported by the National Natural Science Foundation of China (92034302 and 22178347), the Dalian National Laboratory for Clean Energy (DNL) Cooperation Fund, the Chinese Academy of Sciences (DNL201905), the "Transformational Technologies for Clean Energy and Demonstration", Strategic Priority Research Program of the Chinese Academy of Sciences (XDA21030700), the National Science and Technology Major Project (2017-I-0004-0005).

摘要: The coupling of reaction and diffusion between neighboring active sites in the catalyst pore leads to the spatiotemporal fluctuation in component concentration, which is very important to catalyst performance and hence its optimal design. Molecular dynamics simulation with hard-sphere and pseudo-particle modeling has previously revealed the non-stochastic concentration fluctuation of the reactant/product near isolated active site due to such coupling, using a simple model reaction of A → B in 2D pores. The topic is further developed in this work by studying the concentration fluctuation due to such coupling between neighboring active sites in 3D pores. Two 3D pore models containing an isolated active site and two adjacent active sites were constructed, respectively. For the isolated site, the concentration fluctuation intensifies for larger pores, but the product yield decreases, and for a given pore size, the product yield reaches a peak at a certain reactant concentration. For two neighboring sites, their distance (d) is found to have little effect on the reaction, but significant to the diffusion. For the same reaction competing at both sites, larger d leads to more efficient diffusion and better overall performance. However, for sequential reactions at the two sites, higher overall performance presents at a smaller d. The results should be helpful to the catalyst design and reaction control in the relevant processes.

关键词: Molecular dynamics simulation, Concentration fluctuation, Reaction-diffusion coupling, Catalyst

Abstract: The coupling of reaction and diffusion between neighboring active sites in the catalyst pore leads to the spatiotemporal fluctuation in component concentration, which is very important to catalyst performance and hence its optimal design. Molecular dynamics simulation with hard-sphere and pseudo-particle modeling has previously revealed the non-stochastic concentration fluctuation of the reactant/product near isolated active site due to such coupling, using a simple model reaction of A → B in 2D pores. The topic is further developed in this work by studying the concentration fluctuation due to such coupling between neighboring active sites in 3D pores. Two 3D pore models containing an isolated active site and two adjacent active sites were constructed, respectively. For the isolated site, the concentration fluctuation intensifies for larger pores, but the product yield decreases, and for a given pore size, the product yield reaches a peak at a certain reactant concentration. For two neighboring sites, their distance (d) is found to have little effect on the reaction, but significant to the diffusion. For the same reaction competing at both sites, larger d leads to more efficient diffusion and better overall performance. However, for sequential reactions at the two sites, higher overall performance presents at a smaller d. The results should be helpful to the catalyst design and reaction control in the relevant processes.

Key words: Molecular dynamics simulation, Concentration fluctuation, Reaction-diffusion coupling, Catalyst