Chinese Journal of Applied Chemistry ›› 2023, Vol. 40 ›› Issue (6): 896-903.DOI: 10.19894/j.issn.1000-0518.220341

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Preparation of PCN-6(M) Bimetallic Organic Framework Materials by Steam-assisted Method and Their CO2 and CH4 Adsorption Performance

Ning YUAN1, Jie MA1, Jin-Ling ZHANG1, Jian-Sheng ZHANG1,2()   

  1. 1.Shanxi Research Institute for Clean Energy,Tsinghua University,Taiyuan 030032,China
    2.Department of Energy and Power Engineering,Tsinghua University,Beijing 100084,China
  • Received:2022-10-20 Accepted:2023-03-09 Published:2023-06-01 Online:2023-06-27
  • Contact: Jian-Sheng ZHANG
  • About author:zhang-jsh@tsinghua.edu.cn

Abstract:

In this work, a steam-assisted method is used to prepare bimetallic organic framework materials (bimetallic MOFs). Co, Fe, Mn, Zn, and Ni as the secondary metals are exchanged in the structure of PCN-6 which has large specific surface area and high porosity, and a series of PCN-6(M) (M=Co/Fe/Mn/Zn/Ni) bimetallic materials are obtained. Their structure, morphology, composition, and adsorption properties are characterized by powder X-ray diffraction(PXRD), scanning electron microscopy(SEM), energy dispersive spectroscopy(EDS), inductively coupled plasma-atomic emission spectroscopy(ICP-OES), and gas adsorption methods. The results show that the diffraction peaks and morphology of the PCN-6(M) series bimetallic materials are consistent with the parent material PCN-6, and the exchanged metals content reaches 12.1% for Co, 22.0% for Fe, 16.1% for Mn, 17.5% for Zn, and 16.8% for Ni, respectively,which is much higher than the metal exchange capacity of solvothermal method (about 5.0%) under the same conditions. In terms of gas adsorption performance, PCN-6(Zn), PCN-6(Ni) and PCN-6(Co) have better adsorption capacity for CH4 and CO2 than the parent material, especially at low pressure. In addition, the adsorption selectivity of V(CO2)∶V(CH4)=50∶50, PCN-6(Fe) is superior to the parent material by theoretical ideal adsorption solution theory (IAST) calculation. The preparation of bimetallic MOFs by steam-assisted method can improve the exchange capacity of metals and change the affinity of MOFs to different gas molecules, thereby improving the gas adsorption performance and selectivity of materials. The steam-assisted method provides a new idea for the preparation of bimetallic MOFs, which is expected to be used in the preparation of other materials.

Key words: Gas adsorption, CO2/CH4 separation, Steam-assisted method, Bimetallic organic framework materials

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