Single‐Atom Mediated d‐Band Engineering of Platinum Nanocatalysts for High‐Efficiency Acidic Hydrogen Evolution

The rational construction of single‐atom‐mediated Pt catalysts with optimized electronic structures and robust stability remains a grand challenge for hydrogen evolution reaction (HER). Herein, spatial confinement coupled with a d ‐band engineering strategy is pioneered to fabricate cobalt single‐atom coordinated Pt nanocatalysts (Pt@Co‐SAs/NC), achieving exceptional HER activity with ultralow Pt loading (0.94 wt%). The Pt@Co‐SAs/NC exhibits an overpotential of 15 mV at 10 mA cm −2 (η 10 ) and 21.8‐fold enhanced mass activity at 20 mV versus commercial Pt/C, surpassing most reported Pt‐based systems. Synchrotron X‐ray absorption spectroscopy and theoretical studies reveal that the atomically dispersed CoN 4 sites adjacent to Pt NPs serve as electronic modulators, inducing a 0.36 eV downshift of the Pt d ‐band center through interfacial charge redistribution. This electronic engineering weakens hydrogen adsorption strength (Δ G H* = −0.17 eV) while accelerating H 2 desorption kinetics. Furthermore, the CoN 4 ‐anchored carbon matrix suppresses nanoparticle aggregation and ensures exceptional durability through strong metal‐support interactions, maintaining 94.2% activity after 130 h operation. This work establishes an atomic‐level electronic modulation paradigm for designing highly efficient, cost‐effective, and durable electrocatalysts.