Chinese Journal of Catalysis ›› 2016, Vol. 37 ›› Issue (8): 1249-1256.DOI: 10.1016/S1872-2067(16)62462-2

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Co3O4 supported on N, P-doped carbon as a bifunctional electrocatalyst for oxygen reduction and evolution reactions

Yingbin Huanga,b, Min Zhanga, Peng Liua, Faliang Chenga, Lishi Wangb   

  1. a. Guangdong Engineering and Technology Research Center for Advanced Nanomaterials, Dongguan University of Technology, Dongguan 523808, Guangdong, China;
    b. School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou 510640, Guangdong, China
  • Received:2016-01-21 Revised:2016-05-03 Online:2016-07-29 Published:2016-08-01
  • Contact: Faliang Cheng, Lishi Wang
  • Supported by:

    This work was supported by the National Natural Science Foundation of China (21375016, 20475022 and 21505019).

Abstract:

Noble metals, such as platinum, ruthenium and iridium-group metals, are often used as oxygen reduction or evolution reaction (ORR/OER) electrocatalysts. To reduce the cost and provide an application of bifunctional catalysis, in this work, cobalt oxide supported on nitrogen and phosphorus co-doped carbon (Co3O4/NPC) was fabricated and examined as a bifunctional electrocatalyst for OER and ORR. To prepare Co3O4/NPC, NPC was pyrolyzed from melamine and phytic acid supported on carbon, followed by the solvothermal synthesis of Co3O4 on NPC. Linear sweep voltammetry was used to evaluate the activity for OER and ORR. For OER, Co3O4/NPC showed an onset potential of 0.54 V (versus the saturated calomel electrode) and a current density of 21.95 mA/cm2 at 0.80 V, which was better than both Co3O4/C and NPC. The high activity of Co3O4/NPC was attributed to a synergistic effect of the N, P co-dopants and Co3O4. For ORR, Co3O4/NPC exhibited an activity close to commercial Pt/C in terms of the diffusion limited current density (-4.49 vs -4.76 mA/cm2 at -0.80 V), and Co3O4 played the key role for the catalysis. Chronoamperometry (current versus time) was used to evaluate the stability, which showed that Co3O4/NPC maintained 46% current after the chronoamperometry test for OER and 95% current for ORR. Overall, Co3O4/NPC exhibited high activity and improved stability for both OER and ORR.

Key words: Cathode catalyst, Oxygen reduction reaction, Oxygen evolution reaction, Doped carbon, Cobalt