Mn doping of cobalt oxynitride coupled with N-rGO nanosheets hybrid as a highly efficient electrocatalyst for oxygen reduction and oxygen evolution reaction

Abstract

The oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) have aroused extensive concern in recent years due to their attractive energy storage and conversion efficiency. However, the energy conversion efficiency was largely restricted by the sluggish kinetics and the high cost of the catalysts. In this regard, developing non-precious metal materials as low-cost, highly efficient, and durable catalysts is extremely urgent topic. In this work, Mn doping of cobalt oxynitride (Co1-xMnxON) coupled with nitrogen-doped reduced graphene oxide (N-rGO) nanosheets hybrids was created as a bifunctional and highly efficient catalyst toward the ORR and OER. The electrochemical tests indicated that the catalytic performance for the CoMnON/N-rGO has been greatly improved after Mn and N doping. For ORR, the onset potential and half-wave potential are 0.91 V and 0.83 V, respectively. Meanwhile, it manifests a low overpotential of 350 mV at 10 mA cm−2, Tafel slope of 70 mV dec−1 in 1.0 M KOH solution towards OER. The charge transfer rate and specific surface area for the hybrid catalyst dramatically increase with the incorporation of Mn and N. Our work provides a new strategy for developing highly efficient and durable electrocatalysts.