Key Words:Oxygen reduction reaction;Carbides - Carbon black - Charge transfer - Doping (additives) - Electrocatalysts - Electrolytic reduction - Iron oxides - Magnetite - Nanoparticles - Oxygen - Polypyrroles - Porous carbon - Porous materials - Synthesis (chemical)

Abstract:Iron/nitrogen co-doped carbon materials (Fe/N-C) have been extensively investigated as oxygen reduction reaction (ORR) catalysts in alkaline medium. Here, Fe<inf>3</inf>O<inf>4</inf> nanoparticles decorated carbon black is encapsulated with polypyrrole and subsequently utilized as a precursor to synthesize a highly efficient ORR catalyst through pyrolysis. Interestingly, this catalyst consists of yolk-shell Fe@FeN<inf>x</inf> and N-doped porous carbon, demonstrating a synergistically improved ORR activity. It shows better durability, Pt-comparable activity, and superior tolerance against methanol crossover under alkaline conditions. Control experiments confirm that yolk-shell Fe@FeN<inf>x</inf> nanoparticles provide efficient catalytic sites and facilitate charge transfer in ORRs. Thus, this study provides a new kind of Fe/N-C electrocatalyst synthesized to be nitride rather than carbide simply with a heat-treatment under N<inf>2</inf> atmosphere.<br/> © 2020

Volume:829

Issue:wu

Translation or Not:no