Polydopamine-assisted construction of cobalt phosphide encapsulated in N-doped carbon porous polyhedrons for enhanced overall water splitting

Abstract Electrochemical water splitting is widely recognized as an effective strategy for economical both hydrogen and oxygen production. Herein, a facile carbonization-oxidation-phosphidation strategy is proposed to construct a novel nanocomposite consisting of Co x P (a mixture of Co 2 P and CoP) nanoparticles encapsulated in N-doped carbon porous polyhedrons based on surface functionalized ZIF-67, which serves as a high-performance electrode material for overall water splitting. With the merits of highly active Co x P nanoparticles and distinct structure characteristics, the resultant composite exhibits superior catalytic behaviors toward both the hydrogen evolution reaction and oxygen evolution reaction in alkaline electrolytes. When the as-prepared hybrid is adopted as both the cathodic and anodic catalysts in an alkaline medium, the electrolyzer can deliver a current density of 10 mA cm −2 at a low cell voltage of ∼1.71 V. More importantly, this work sufficiently proves that surface engineering route is feasible to develop high-efficiency bifunctional electrocatalysts toward overall water splitting application.