Synergistic Hydrogen Microenvironment Modulation Enabling Superior Hydrogen Evolution Reaction Activity in Neutral Media

The neutral hydrogen evolution reaction (HER) shows significant development prospects but remains challenging, caused by strong hydrogen-bonding network and low proton supply rate. Taking HER-inert nickel-iron layered double hydroxide (LDH) as an example, we illustrate that Ni nanoparticles (Ni NPs) decoration and tungstate intercalation can synergistically modulate the hydrogen microenvironment of LDH to boost the neutral HER activity. Theoretical simulations and operando electrochemical characterizations validate that the decorated Ni NPs can enhance local electric field, thereby disrupting hydrogen-bonding network to render the accessibility of free water molecules and enriching H₃O⁺, as well as promote water dissociation. By regulating the local electronic structure of LDH, the intercalated-tungstate effectively accelerates the dehydration kinetics of hydrated sodium ions, facilitates the spillover of H^*, optimizes H^* adsorption/recombination, and also intensifies the enrichment of H₃O⁺. As expected, the Ni NPs and tungstate co-modified LDH manifests splendid neutral HER activity with an ultralow overpotential of 14 and 239 mV at 10 and 1000 mA cm^-2, respectively. Moreover, an outstanding stability of 600 h at the industrial current density of 1000 mA cm^-2 is achieved. The synergistic hydrogen microenvironment modulation provides a new insight into the design of efficient neutral HER electrocatalysts.