Ultrafine Fe2C in porous N-doped carbon by Polydopamine−Silane Co-deposition for efficient oxygen reduction reaction and zinc-air battery

Pt-based electrocatalysts in oxygen reduction reaction (ORR) have notably frustrated the large-scale application in the relevant energy technologies. Alternatively, polydopamine (PDA)-based materials have displayed great potential due to its adhesive uniqueness, componential and structural tailorability, but the inferior surface area due to the intrinsically dense coating of PDA is an imperfection. Herein, with 3-aminopropyltriethoxysilane (APTS), one mutual deposition method with organic PDA and inorganic APTS was proposed for ultrafine Fe2C embedded into porous N-doped carbon (Fe/PNC), benefitting from synergistic effect of the PDA-derived carbon and APTS-derived SiO2 components produced from the pyrolysis of PDA-APTS hybrid, which can confine metal species more robustly than single PDA, together with the internal pore-making capacity. Accordingly, the as-obtained sample exhibits superior alkaline ORR activity with a half-wave potential of 0.87 V as well as robust long-time durability and strong poison tolerance. Additionally, the constructed zinc–air battery using Fe/PNC as cathode presents higher peak power density and much stronger long-time charge-discharge stability than Pt/C. Such strategy would be generally applicable for the rational design of highly-quality metal-based functional composites.