Interfacial-Free-Water-Enhanced Mass Transfer to Boost Current Density of Hydrogen Evolution

The advancement of water electrolysis highlights the growing importance of electrolyzers capable of operating at high current densities, where mass transfer dynamics plays a crucial role. In the electrode reactions, the interfacial water is a key factor in regulating these dynamics. However, the potential of utilizing interfacial-free water (IFW) to modulate electrode behavior remains underexplored. Herein, we investigate the effect of interfacial water structure on hydrogen evolution reaction (HER) performance across different current density ranges, using designed platinum-coated nickel hydroxide on nickel foam (Pt@Ni(OH)2-NF) electrodes. We reveal that with increasing current density, changes in interfacial water structure alter the rate-determining step of the HER. Pt@Ni(OH)2-NF exhibited excellent performance in alkaline electrolytes, achieving 1000 mA cm-2 at 114 mV overpotential. This study provides a novel approach to optimizing alkaline water electrolysis dynamics by enhancing mass transfer, further paving the way for more efficient and energy-saving hydrogen production.