Chinese Journal of Catalysis ›› 2018, Vol. 39 ›› Issue (12): 1869-1880.DOI: 10.1016/S1872-2067(18)63153-5

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Effect of the support on cobalt carbide catalysts for sustainable production of olefins from syngas

Xinxing Wanga,b, Wen Chena, Tiejun Lina, Jie Lia, Fei Yua,b, Yunlei Ana,b, Yuanyuan Daia,b, Hui Wanga, Liangshu Zhonga,c, Yuhan Suna,c   

  1. a CAS Key Laboratory of Low-Carbon Conversion Science and Engineering, Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai 201203, China;
    b University of Chinese Academy of Sciences, Beijing 100049, China;
    c School of Physical Science and Technology, ShanghaiTech University, Shanghai 201203, China
  • Received:2018-07-02 Revised:2018-07-31 Online:2018-12-18 Published:2018-09-26
  • Contact: 10.1016/S1872-2067(18)63153-5
  • Supported by:

    This work was supported by the National Key R&D Program of China (2017YFB0602202), the National Natural Science Foundation of China (21573271, 91545112, and 21703278), the Key Research Program of Frontier Sciences, CAS (QYZDB-SSW-SLH035), the Strategic Priority Research Program of the Chinese Academy of Sciences (XDA21020600), and SARI Interdisciplinary Youth Innovation Research Funding (171001).

Abstract:

Co2C-based catalysts with SiO2, γ-Al2O3, and carbon nanotubes (CNTs) as support materials were prepared and evaluated for the Fischer-Tropsch to olefin (FTO) reaction. The combination of catalytic performance and structure characterization indicates that the cobalt-support interaction has a great influence on the Co2C morphology and catalytic performance. The CNT support facilitates the formation of a CoMn composite oxide during calcination, and Co2C nanoprisms were observed in the spent catalysts, resulting in a product distribution that greatly deviates from the classical Anderson-Schulz-Flory (ASF) distribution, where only 2.4 C% methane was generated. The Co3O4 phase for SiO2-and γ-Al2O3-supported catalysts was observed in the calcined sample. After reduction, CoO, MnO, and low-valence CoMn composite oxide were generated in the γ-Al2O3-supported sample, and both Co2C nanospheres and nanoprisms were identified in the corresponding spent catalyst. However, only separated phases of CoO and MnO were found in the reduced sample supported by SiO2, and Co2C nanospheres were detected in the spent catalyst without the evidence of any Co2C nanoprisms. The Co2C nanospheres led to a relatively high methane selectivity of 5.8 C% and 12.0 C% of the γ-Al2O3-and SiO2-supported catalysts, respectively. These results suggest that a relatively weak cobalt-support interaction is necessary for the formation of the CoMn composite oxide during calcination, which benefits the formation of Co2C nanoprisms with promising catalytic performance for the sustainable production of olefins via syngas.

Key words: Fischer-Tropsch to olefins, Cobalt carbide, Supported catalyst, Olefin, Syngas