Solvent‐Free Chemical Approach to Synthesize Co Nanoparticles Supported on N‐doped Porous Carbon for Efficient Electrocatalytic Oxygen Reduction

Abstract Transition metal/N‐doped carbon materials are the most promising alternative to expensive Pt‐based electrocatalysts for oxygen reduction reaction (ORR). In this paper, we design hierarchical three‐dimensional (3D) Co nanoparticles supported on N‐doped carbon (Co/N−C) with abundant defects using a simple solvent‐free strategy. With the help of templates, Co nanoparticles are embedded in the interconnected porous carbon network derived from phenolic resin, and Co/N−C is obtained after the introduction of N atoms. Benefitting from the coupling effect of Co and N in carbon matrix, Co/N−C exhibits better electrocatalytic performance than porous N‐doped carbon (N−C) for ORR in alkaline medium. The Co/N−C shows a dominant four‐electron transfer toward oxygen reduction with a rather high half‐wave potential of 0.82 V versus relative hydrogen electrode (vs. RHE), as well as good stability and methanol tolerance. The crumpled porous 3D structure of Co/N−C with a high specific surface area facilitates the formation of N‐contained defects as active sites, and boosts the transport of electrons and ions. Our work provides a feasible way to design non‐noble metal electrocatalysts with satisfied properties for ORR.