A MOF derived hierarchically porous 3D N-CoP /Ni2P electrode for accelerating hydrogen evolution at high current densities

Hydrogen evolution reaction is a critical reaction in water splitting for hydrogen production. However, developing effective and stable non-noble-metal electrocatalysts which work well at high current densities demanded by industry still remain great challenge. Herein, taking advantage of the highly tunable metal-organic framework (MOF) templates, nitrogen doped binary transition metal phosphides electrocatalysts (N-CoPx/Ni2P) with three-dimensional (3D) conductive network structure were successfully synthesized. The 3D open porous channels could expose more catalytically active sites; nitrogen doping and the synergistic effect between CoP and Ni2P can increase the electron density of Co atoms at active sites, further optimizing the Gibbs free energy of hydrogen (ΔGH*) and water (ΔGH2O*). As a result, the obtained N-CoPx/Ni2P catalyst exhibits extraordinary electrocatalytic activity in a wide pH range. Especially, it requires an extremely low overpotential of 152 mV to deliver a high current density of 650 mA cm–2 in alkaline media. This work may shed some light on the rational design of cheap electrocatalysts and electrode materials that work well at high current densities.