Chinese Journal of Catalysis ›› 2018, Vol. 39 ›› Issue (7): 1228-1239.DOI: 10.1016/S1872-2067(18)63055-4

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Surface density of synthetically tuned spinel oxides of Co3+ and Ni3+ with enhanced catalytic activity for methane oxidation

Zeshu Zhanga,b,c, Jingwei Lia,b, Ting Yia,b,d, Liwei Suna,b,c, Yibo Zhanga,b, Xuefeng Hua,b,c, Wenhao Cuid, Xiangguang Yanga,b   

  1. a State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, Jilin, China;
    b Jilin Province Key Laboratory of Green Chemistry and Process, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, Jilin, China;
    c University of Science and Technology of China, Hefei 230026, Anhui, China;
    d University of Chinese Academy of Sciences, Beijing 100049, China
  • Received:2018-01-08 Revised:2018-02-10 Online:2018-07-18 Published:2018-06-07
  • Contact: 10.1016/S1872-2067(18)63055-4
  • Supported by:

    This work was supported by the National Key Research and Development Program of China (2016YFC0204301).

Abstract:

Spinel oxides containing Co and Ni are a promising substitute as a noble metal catalyst for methane combustion. Achieving a complete oxidation of methane under 400℃ remains challenging, and whether Ni3+ or Co3+ is the active center for the catalytic combustion of methane is a controversial issue. Therefore, we designed a series of spinel oxide catalysts by exposing different amounts of Ni3+ and Co3+ deposited on the surface by hydrothermal and co-precipitation methods in order to study the influence of high oxidation state (Ni3+ and Co3+) on surface and catalytic activity. The catalytic performance increased almost linearly with increasing Ni3+ + Co3+ on the surface of the catalyst. Thus, we are convinced that Ni3+ and Co3+ both act as active centers. The amount of Ni3+ + Co3+ on a hydrothermal 60 h NiCo2O4 nanosheet surface is the highest, and reveals the best catalytic performance with T50 (50% methane conversion) at about 280℃. 10 vol% H2O added to the system has little impact on activity, especially at high space velocities due to the long hydrothermal time with less absorbed oxygen species and crystal defects. Overall, these results help clarify methane activation mechanisms and aid the development of more efficient low-cost catalysts.

Key words: Spinel oxides, Catalytic combustion of methane, Porous nanosheets, Active center, Hydrothermal stability