Single-Atom Catalysts with Microenvironment Tuned by High Entropy for Efficient and Stable Alkaline Hydrogen Evolution Reaction

Conventional non-noble hydrogen evolution reaction catalysts are plagued by excessive hydrogen adsorption and instability. To overcome this, we pioneer a high-entropy single-atom (HESA) catalyst via precise anchoring of multiple transition metals on carbon supports. The HESA catalyst achieves record-breaking alkaline HER performance of 44 mV@10 mA cm −2 (matching commercial Pt/C catalyst) and 300 h stability, resolving the persistent activity-stability trade-off. Systematical characterizations reveal that low-coordination metal sites induce significant metal-support charge redistribution. Electronegative supports withdraw electrons from metal centers, while π-back-donation downshifts metal d-band centers, optimizing the Gibbs free energy of intermediate H atoms (ΔG H* ). Atomic-scale imaging further confirms uniform charge distribution and Ångström-level electric field response. Crucially, adjacent multi-metal sites synergistically lower energy barriers for both water dissociation and hydrogen desorption through a synergistic electronic buffering effect. This work establishes entropy-driven microenvironment engineering as a paradigm for cooperative optimization of active sites and electronic structures, opening avenues for durable non-precious catalysts.