High‐Density Hydrogen Pump Channels Enable Efficient Alkaline Hydrogen Evolution for Pt Catalysts at High Current Densities

In alkaline electrolytes, the sluggish water dissociation at Pt sites, particularly under high current densities, leads to scarce adsorbed hydrogen ( ∗ H) and inferior hydrogen evolution reaction (HER) activity, making adequate ∗ H supply critical yet challenging for optimizing the HER performance of Pt‐based catalysts. By constructing high‐valent Ru within the Pt (111) facet, we successfully constructed high‐density Ru‐Pt hydrogen‐pump channels in Ru‐Pt/C catalyst, which effectively promotes the rapid transfer of abundant ∗ H generated at Ru sites toward Pt. In situ X‐ray absorption fine structure and theoretical simulations reveal that Ru maintains a higher oxidation state than Pt during the HER process, which ensures the persistent existence of the built‐in electric field between Ru and Pt and the spontaneous replenishment of ∗ H to Pt sites. Consequently, Ru‐Pt/C delivers markedly enhanced HER activity relative to Pt/C, and this enhancement becomes more pronounced with the current density increase (from 10 to 1000 mA cm −2 ). Meanwhile, the assembled anion exchange membrane water electrolyzer achieves 1 A cm −2 at only 1.77 V with 300 h of stable operation. This work demonstrates the key role of high‐density hydrogen‐pump channels in the design of high‐performance Pt‐based catalysts under high‐current‐density conditions in alkaline environments.