Synthesis of Fe3C@C core-shell catalysts with controlled shell composition for robust oxygen evolution reaction

Abstract In this study, iron carbide (Fe3C) particles were encapsulated in graphitic carbon shells by a facile carbonation process. These core-shell carbides, in which iron carbide is encapsulated in graphene-like layer (Fe3C@C) and nitrogen doped graphene-like layer (Fe3C@C–N) were investigated as oxygen evolution reaction (OER) catalysts to investigate the effect of the carbon shell on catalyst activity and stability. Due to the protective effect of the graphitic carbon shells, the performance of Fe3C@C and Fe3C@C–N were considerably better than the bare Fe3C nanoparticles. The OER activity of Fe3C@C–N is comparable with that of carbon-supported ruthenium oxide (RuO2/C), and this core-shell carbide has a remarkable stability and high turnover frequency under alkaline conditions. To elucidate the real active sites of these core-shell carbides, the role of the Fe3C core, Fe–Nx active sites, and effect of nitrogen doping in the shell were investigated in detail.