Fe-Induced Electronic Transfer and Structural Evolution of Lotus Pod-Like CoNiFePx@P,N-C Heterostructure for Sustainable Oxygen Evolution

Transition metal phosphides with metallic properties are a promising candidate for electrocatalytic water oxidation, and developing highly active and stable metal phosphide-based oxygen evolution reaction catalysts is still challenging. Herein, we present a facile ion exchange and phosphating processes to transform intestine-like CoNiP_x@P,N-C into lotus pod-like CoNiFeP_x@P,N-C heterostructure in which numerous P,N-codoped carbon-coated CoNiFeP_x nanoparticles tightly anchors on the 2D carbon matrix. Meanwhile, the as-prepared CoNiFeP_x@P,N-C enables a core-shell structure, high specific surface area, and hierarchical pore structure, which present abundant heterointerfaces and fully exposed active sites. Notably, the incorporation of Fe can also induce electron transfer in CoNiP_x@P,N-C, thereby promoting the oxygen evolution reaction. Consequently, CoNiFeP_x@P,N-C delivers a low overpotential of 278 mV (vs RHE) at a current density of 10 mA cm^-1 and inherits excellent long-term stability with no observable current density decay after 30 h of chronoamperometry test. This work not only highlights heteroatom induction to tune the electronic structure but also provides a facile approach for developing advanced and stable oxygen evolution reaction electrocatalysts with abundant heterointerfaces.