Developing Schottky high-controductivity Ti3C2TX MXene/Ni2P/NF heterojunction with modulating surface electron density to boost hydrogen evolution reaction

Abstract

Nickel-based transition metal electrocatalysts for water electrolysis are promising alternatives to precious metal based electrocatalysts, due to their high activity, low cost, and relatively high stability, offering broad prospects for application in hydrogen production via water electrolysis. Modifying nickel-based transition metal electrocatalysts with phosphorus elements and Schottky heterojunction interfaces can influence the electronic state of the metal, thus enhance the electrocatalytic performance of the catalyst. In this study, a phosphor modified nickel-based electrocatalyst, i.e. MXene/Ni₂P/NF electrode material was obtained by assembling Ni₂P nanosheets on a nickel foam (NF) substrate and then depositing MXene nanosheets onto the surface of Ni₂P/NF via electrophoretic deposition. Water droplets can wet the interior of the electrode material within 150 ms (below the detection limit), demonstrating excellent hydrophilicity, which facilitates the wettability of the electrolyte and the adsorption/desorption of reaction intermediates. Electrochemical tests revealed that the MXene/Ni₂P/NF electrode exhibits an overpotential of only 94 mV at a current density of 10 mA cm⁻², with a Tafel slope of 83.7 mV dec⁻¹, in the hydrogen evolution reaction. The overpotential remains virtually unchanged after a 24-h stability test.