Confinement of Pt ₃ Co by Carbon Nanomesh to Accelerate H–OH Cleavage in Alkaline Hydrogen Evolution

Supported alloys can lower alkaline water dissociation barrier via dual‐metal synergy. However, weak support‐alloy interactions usually bottleneck interfacial charge transfer and thus impede water dissociation. Herein, metal‐support interfacial engineering is exploited to construct a microporous carbon nanomesh (MCN) that tightly bridges Pt 3 Co nanoparticles to carbon nanotubes (CNT@Pt 3 Co‐MCN) by confinement. Computation indicates that this confinement effect of MCN endows Pt with additional electrons, thereby enhancing its electrostatic attraction toward the hydrogen atoms of water molecules. This significantly promotes water activation by facilitating hydrogen abstraction, accelerating the cleavage of the H–OH bond. Thus, the CNT@Pt 3 Co‐MCN achieves a low voltage (1.939 V) and excellent stability in alkaline membrane electrode assemblies. This work offers a general interfacial‐engineering paradigm to tailor support‐metal interaction for efficient water dissociation over alloy catalysts in alkaline.