Highly dispersed CoP on three-dimensional ordered mesoporous FeP for efficient electrocatalytic hydrogen production

Abstract

Electrocatalytic hydrogen production is hindered by the high cost or low efficiency of electrocatalysts. In this work, we synthesized a highly dispersed CoP on 3-dimensional ordered mesoporous FeP (CoP@3DOM-FeP) for efficient electrocatalytic hydrogen evolution reaction (HER). The uniform surface decoration of CoP on a 3D porous iron framework is achieved by delicately embedding ZIF-67 in polystyrene (PS) nanospheres, followed by the removal of templates and chemical vapor deposition (CVD) of phosphorus. Owing to the well dispersed active site CoP and the excellent 3D FeP substrate with high porosity and conductivity, the present CoP@3DOM-FeP demonstrated high efficiency in the electrocatalytic HER, with overpotentials as low as of 67.2, 71.1 and 76.5 mV at a current density of 10 mA cm⁻² in alkaline, neutral, and acidic electrolytes. Moreover, low Tafel slopes ranging from 66.3–77.5 mV dec⁻¹ of the as-prepared electrocatalyst indicate that the Volmer–Heyrovsky mechanism dominated the surface hydrogen generation process with fast electron transfer kinetics. The developed nano-engineering strategy for surface decoration of active sites on a 3D porous substrate enables an extremely low amount of cobalt usage but a maximized exposure of active sites. Hence, this work not only proposes a cost-effective, efficient, and robust cobalt-based electrocatalyst in all-pH HER, but also paves the way for developing next-generation nano-engineered electrocatalysts.