Cobalt Phosphide Hollow Polyhedron as Efficient Bifunctional Electrocatalysts for the Evolution Reaction of Hydrogen and Oxygen

Abstract

The development of efficient and low-cost hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) electrocatalysts for renewable energy conversion techniques is highly desired. A kind of polyhedral cobalt phosphide (CoP Polyhedrons) is developed as efficient bifunctional electrocatalysts for HER and OER templated by Co-centered metal-organic frameworks (MOFs). The as-prepared CoP Polyhedrons, which have large specific surface area and high porosity providing rich catalytic active sites, show excellent electrocatalytic performances for both HER and OER in acidic and alkaline media, respectively, with onset overpotentials of 35 and 300 mV, Tafel slopes of 59 and 57 mV dec-1 and current densities of 10 mA cm-2 at overpotentials of 159 and 400 mV for HER and OER, respectively, which are remarkably superior to particulate CoP (CoP Particles) and comparable to commercial noble metal catalysts. In addition, the CoP Polyhedrons also show good durability after long-term operations.