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

The design of cheap, efficient, and durable electrocatalysts for high‐throughput H 2 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 (Δ G diss = −1.2 eV) and optimized hydrogen adsorption ability (Δ G 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 cm 2 membrane electrode assembly (MEA) electrolyzer reach a high H 2 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.