Core-double shell templated Fe/Co anchored carbon nanospheres for oxygen reduction

Propelled by the demand of cost-effective and sustainable electrocatalysts, non-precious catalysts are beginning to spark tremendous interest. Among them, carbon-based materials are able to load various active sites ranging from metallic (Ni, Fe, Co, and Mn) and non-metallic elements (B, P, S, and N). In this study, a novel reactive core-double shell template strategy was exquisitely designed to synthesize Fe-C and Co-C hybrids anchored on Nitrogen-doped hollow carbon nanospheres (Fe/Co@NDHC). Fe₃O₄ microsphere plays as the core, and polyaniline (PANI) and zeolitic imidazolate framework-67 (ZIF-67) is the inner and outer shell, respectively. Thanks to the synergistic effect between interconnected multiple active sites and unique porous hollow structure, the as-prepared Fe/Co@NDHC exhibited an outstanding Oxygen Reduction Reaction (ORR) performance with a half-wave potential (E_1/2) of 0.918 V in alkaline media, as well as a superior tolerance to methanol and a long-term stability. The synergetic effects of Fe-C, Co-C and pyridinic-N active sites were further confirmed by density functional theory calculations. This reactive templated method offers a new way to fabricate heteroatom doped materials with a controlled morphology for diverse energy-related applications.