Catalyst Support in Oxygen Electrocatalysis: A Case Study with CoFe Alloy Electrocatalyst

Abstract

Synthesis of a highly efficient oxygen electrocatalyst is of significant interest for the development of energy storage devices. The electronic and surface structure, shape, size, and catalyst support largely control the electrocatalytic activity. We demonstrate the synthesis of bifunctional CoFe alloy electrocatalysts encased in nitrogen-doped graphitic carbon (N-C-CoFe) and supported on nitrogen-doped reduced graphene oxide (N-rGO-CoFe) for the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) and the influence of catalyst support on the electrocatalytic performance. N-C-CoFe and N-rGO-CoFe were synthesized from a single-source precursor, potassium cobalt hexacyanoferrate multimetal complex, by thermal annealing. Both catalysts efficiently catalyze ORR and OER at low overpotential. The benchmark current density of 10 mA/cm2 for OER is obtained at very low overpotentials of 0.22 and 0.29 V with N-rGO-CoFe and N-C-CoFe, respectively. The N-C-CoFe catalyst is highly durable toward OER and...