Hierarchical Crystalline/Amorphous Heterostructure MoNi/NiMoOx for Electrochemical Hydrogen Evolution with Industry-Level Activity and Stability

The design of cheap, efficient, and durable electrocatalysts for high-throughput H₂ production is critical to give impetus to hydrogen production from fundamental to practical industrial applications. Here, a hierarchical heterostructure hydrogen evolution reaction (HER) electrocatalyst (MoNi/NiMoO_x) with 0D MoNi nanoalloys nanoparticles embedded on well-assembled 1D porous NiMoO_x microrods in situ grown on 3D nickel foam (NF) is successfully constructed. The synergetic effect of different building units in the unique hierarchical structure endows the MoNi/NiMoO_x composites with the highly active heterogeneous interface with low water dissociation energy (ΔG_diss = −1.2 eV) and optimized hydrogen adsorption ability (ΔG_H* = −0.01 eV), fast electron/mass transport, and strong catalyst-support binding force. As a result, optimal MoNi/NiMoO_x exhibits an ampere-level current density of 1.9 A cm⁻² at an ultralow overpotential of 139 mV in 1.0 м KOH and 289 mV in 1.0 м PBS solution, respectively. Particularly, scaled-up MoNi/NiMoO_x electrodes in a 10 × 10 cm² membrane electrode assembly (MEA) electrolyzer reach a high H₂ production rate of 12.12 L h⁻¹ (12.12 times than that of commercial NF) and exhibit ultralong stability of 1600 h, verifying its huge potential for industrial hydrogen production.