Hydrogen Evolution Performance of a Co-Doped MoNi4 Electrode Prepared by Laser Direct Writing Technology

Abstract

The alkaline hydrogen evolution reaction (HER) is a promising pathway for the large-scale production of green hydrogen. Due to the high water dissociation energy barrier in alkaline media, high energy consumption is required. In this work, a Co-doped MoNi4 self-supported electrode (Co-MoNi4/NM) prepared by laser direct writing (LDW) is reported as an efficient electrocatalyst for HER. The introduction of Co hinders the long-range ordered growth of the MoNi4 single phase, creating a MoNi4/Mo/Ni multiphase heterostructure with rich geometric defects. The electron-rich catalyst weakens the O–H bonds of water molecules, increasing the proportion of free water to provide reactants for subsequent water dissociation. As a result, Co-MoNi4/NM exhibits high HER catalytic performance with an overpotential of 131.2 mV at a current density of 100 mA cm–2. Under simulated industrial conditions (6 M KOH, 60 °C), the electrode demonstrates exceptional HER kinetics with a low overpotential of 227.8 mV at 1 A cm–2 and robust chronopotentiometric durability for 100 h. Furthermore, the assembled two-electrode electrolyzer (Co-MoNi4/NM || Co-MoNi4/NM) delivers a high current density of 1 A cm–2 at a low cell voltage of 1.74 V with long-term operational stability. This study elucidates the mechanism of interfacial water reconstruction driven by electronic modulation, offering a technological paradigm for developing highly efficient industrial-grade electrodes for hydrogen production.