(661g) A MOF-derived hierarchically porous 3D N-CoPx/Ni2P electrode for accelerating hydrogen evolution at high current densities

Hydrogen evolution reaction (HER) 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 (TMPs) electrocatalysts (N-CoP_x/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_x and Ni₂P can increase the electron density of Co atoms at active sites, further optimizing the Gibbs free energy of hydrogen (ΔG_H*) and water (ΔG_H2O*). As a result, the obtained N-CoP_x/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.