Engineering of surface metal–nitrogen moieties in Fe–V based hybrid electrocatalysts for enhanced water oxidation

Abstract

Surface metal–nitrogen moieties, combining the advantages of structural and electronic properties, have been promising for electrocatalytic water oxidation. Here, we report a highly efficient Fe–V based hybrid electrocatalyst by fabricating active metal nitrides (FeN, Fe₃N and VN) on the Fe–V oxide surface. Structural and chemical state characteristics reveal that the Fe–N and V–N moieties are confined to the Fe–V oxide surface lattice, which not only gives rise to electrochemically active sites, but also facilitates electron transfer for the oxygen evolution reaction (OER). More importantly, the metal–nitrogen moieties undergo surface reconstruction to form an iron (oxy)hydroxide active layer during the OER process, which promotes electron flow from V to Fe sites via the bridging oxygen, greatly benefiting the O₂ release from the Fe sites.