Manipulating Alkaline Hydrogen Evolution Reaction by Constructing Layered Interfacial Water

The intrinsically sluggish kinetics of the hydrogen evolution reaction (HER) in alkaline media are a long‐standing challenge in electrocatalysis. Such slow kinetics originated from the water structure at the electrocatalytic interface, yet a general strategy to modulate interfacial water remains elusive. Here, we use C 60 nanorod substrates to construct layered water structure at electrocatalytic interfaces, boosting HER across diverse catalysts. In situ characterizations and electrochemical analysis reveal that the layered interfacial water facilitates rapid K + ‐H 2 O transfer through the electric double layer, cutting the HER energy barrier. When applied to Pt, this design achieves a more than 140% increasement in exchange current density and a 3.19‐fold higher turnover frequency compared to commercial Pt/C, while stably operating at 500 mA cm −2 for over 1000 h in an anion exchange membrane cell. This work establishes interfacial water engineering as a universal lever for manipulating alkaline HER kinetics, with implications for catalyst design beyond hydrogen evolution.