Molten salt electrochemical modulation of Ni/Co nanoparticles onto N-doped carbon for oxygen reduction

Activation of oxygen over non-precious materials has been an imperative task to develop efficient electrochemical energy storage and conversion such as fuel cells and metal-air batteries. Herein, a molten salt electrochemical modulation of metal-nitrogen-carbon based compounds (M–N–C) is achieved. By electrochemical treatment of polydopamine-coated NiCo2O4 (NiCo2O4@PDA) in molten Li2CO3-Na2CO3-K2CO3 at 500 °C, Ni/Co bimetal-nitrogen-carbon catalyst (denoted as Ni/[email protected]) consisting of Ni-Co nanoparticles anchoring on porous nitrogen-doped carbon is constructed and evaluated as electrocatalysts towards the oxygen reduction reaction (ORR). Experimental and calculation results confirm that alloying of Ni-Co and nitrogen doping to carbon enhances the rate-determining transformation of *OH intermediate during ORR. The Ni/[email protected] hence shows an ORR activity comparable with the commercial Pt/C.