CoP nanoparticles embedded in P and N co-doped carbon as efficient bifunctional electrocatalyst for water splitting

Abstract

Noble-metal-free hydrogen/oxygen evolution reaction (HER/OER) electrocatalysts, especially bifunctional electrocatalysts, are essential for overall water splitting, but their performance is impeded by many factors like poor electrical conductivity. Herein, we fabricated cobalt phosphide (CoP) nanoparticles embedded in P and N co-doped carbon (PNC) matrix (CoP@PNC) to fully realize the high activity of CoP by maximizing its conductivity. Simply a carbonization coupled phosphidation approach was utilized where Co ions and organic ligands of Co-MOF were transferred into CoP and P and N co-doped carbon. The synthesized material shows an ideal electrical conductivity, excellent HER (overpotential of −84 mV and −120 mV @10 mA cm−2 in acidic and alkaline medias, respectively) and OER (overpotential of 330 mV@10 mA cm−2 in alkaline media) performances. Further, CoP@PNC acts as a superior catalyst for both anode and cathode to catalyze overall water splitting and only requires an voltage of 1.52 V to deliver a current density of 10 mA cm−2, superior to the noble-metal catalysts system (Pt/C//IrO2) and the reported noble-metal-free bifunctional electrocatalysts.