Chinese Journal of Catalysis ›› 2020, Vol. 41 ›› Issue (12): 1818-1825.DOI: 10.1016/S1872-2067(20)63624-5

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Low-temperature synthesis of ultrasmall spinel MnxCo3-xO4 nanoparticles for efficient oxygen reduction

Chengxiang Shia, Sana Ullaha, Ke Lia, Wei Wanga, Rongrong Zhanga, Lun Pana,b, Xiangwen Zhanga,b, Ji-Jun Zoua,b   

  1. a Key Laboratory for Green Chemical Technology of the Ministry of Education, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China;
    b Collaborative Innovative Center of Chemical Science and Engineering(Tianjin), Tianjin 300072, China
  • Received:2020-02-19 Revised:2020-03-27 Online:2020-12-18 Published:2020-08-14
  • Supported by:
    This work was supported by the National Natural Science Foundation of China (21676193, 51661145026).

Abstract: Spinel-type manganese-cobalt oxides have been regarded as important class of electrocatalysts for oxygen reduction reaction (ORR). However, they are usually synthesized through oxidation-precipitation under aqueous ammonia and then crystallization at high temperature (150-180 ℃), which not only increases the energy consumption but also induces the growth of particles that is unfavorable for ORR. Herein, through a facile precipitation-dehydration method, ultrasmall spinel manganese-cobalt oxide nanoparticles (~5 nm) homogeneously dispersed on conductive carbon black (MnxCo3-xO4/C) were fabricated at low temperature (60 ℃). And the bimetallic composite oxide (Mn1.5Co1.5O4/C) with cubic spinel structure and high Mn content exhibits remarkable enhancement of ORR activity and stability compared with single metal oxide (both Mn3O4/C and Co3O4/C). The essential reason for the enhancement of activity can be attributed to the presence of the mixed Mn3+ and Mn4+ cations in Mn1.5Co1.5O4/C. Moreover, the ORR activity of Mn1.5Co1.5O4/C is comparable to that of commercial 20 wt% Pt/C, and the relative current density only decreases 1.4% after 12 h test, exceeding that of Pt/C and most reported manganese-cobalt oxide electrocatalysts.

Key words: Oxygen reduction reaction, Spinel Mn1.5Co1.5O4, Low-temperature, Precipitation-dehydration method, Ultrasmall nanoparticle