Nanocomposite of Graphene-Phosphorene Structures with Cobalt Phosphide as Effective Electrocatalyst for Hydrogen Evolution Reaction in Acidic Medium

Abstract

Materials containing cobalt phosphide nanoparticles are among the most promising electrocatalysts for the hydrogen evolution reaction in terms of the ratio of activity, cost and durability. This work presents a simple and effective approach for obtaining a nanocomposite of graphene-phosphorene structures decorated with CoP nanoparticles 2–5 nm in size. The nanocomposite was obtained by electrochemical exfoliation of black phosphorus followed by solvothermal synthesis carried out in the presence of few-layer graphene structures doped with nitrogen atoms in a solution containing Co2+ ions. It has been established that the obtained electrocatalyst demonstrates high activity and stability towards hydrogen evolution reaction in an acidic medium. In order to achieve a current density of 10 mA cm–2, an overpotential of ~220 mV is required, while the Tafel slope is ~63 mV dec–1. It has been suggested that this result is due to both the synergistic effect of the interaction between graphene and phosphorene structures and the electrocatalytic activity of nanosized CoP particles present at the edges of phosphorene structures.