Molybdenum carbide promotion on Fe–N-doped carbon nanolayers facilely prepared for enhanced oxygen reduction

Abstract

The catalysts towards the oxygen reduction reaction (ORR) are the key materials for fuel cells and have stimulated continuous investigations on rational designs. Apart from the popular strategies reported, we demonstrate here a facile method resulting in a nanocomposite composed of molybdenum carbide (Mo₂C) nanoparticles embedded and buried in Fe–N-doped carbon nanolayers by directly pyrolyzing the mixture of Fe₂(MoO₄)₃ and dicyandiamide. The underlying Mo₂C donates electrons of higher energy to the exterior N-containing carbon nanolayers (NC) and strongly couples with the active sites induced by Fe in the NC layer, leading to significant improvement at half-wave potential with respect to the control sample without Mo₂C. The catalyst as a whole exhibits a fairly good ORR performance comparable to commercial Pt/C. Moreover, the method is extremely simplified and the material shows better long-term stability and tolerance to the methanol crossover in comparison with Pt/C.