Facile synthesis of cobalt cluster-CoNx composites: synergistic effect boosts electrochemical oxygen reduction

Abstract

Cobalt-based electrocatalysts have been well exploited in oxygen reduction reactions (ORR) for potential applications in alkaline-based fuel cells. In this study, we report a one-pot protocol to prepare facile Co/CoN_x–C electrocatalysts, which are comprised of metallic Co⁰ clusters simultaneously integrated with Co^IIN_x species on N-doped carbon matrixes. The optimized Co/CoN_x–C exhibits high ORR activity in terms of E_onset (0.926 V vs. RHE) and E_1/2 (0.853 V) and shows good stability and methanol tolerance compared with the benchmark Pt/C in an alkaline electrolyte. The enhanced ORR performance arises from the unique integration and synergetic effect of Co clusters with adjacent single-atomic CoN_x sites in the resultant Co/CoN_x–C electrocatalysts, which is further substantiated by density functional theory simulations. This scalable synthesis strategy provides a perspective for design of highly efficient non-noble metal electrocatalysts, encouraging extensive utilization for electrochemical energy conversion.