Energy‐Efficient Electrocatalytic Semi‐Hydrogenation of Alkynols by Synergistic Ni‐Fe Pairs and Ni Clusters on N‐Doped Carbon

Abstract

ABSTRACT Electrocatalytic semi‐hydrogenation (ECSH) of alkynes using water as a hydrogen source is expected to provide a revolutionary solution for upgrading the traditional hydrogenation process. An ingenious design of the electrocatalyst is required to break the tradeoff between activity, selectivity, and Faradaic efficiency (FE). Herein, a non‐noble metal catalytic system, containing well‐defined Ni‐Fe atom pairs and Ni clusters on N‐doped carbon, is constructed by a two‐step annealing method for energy‐efficient ECSH of alkynols. The optimized catalyst with collaborative Ni‐Fe pairs and Ni clusters effectively suppresses hydrogen evolution reaction (HER) competition and C═C over‐hydrogenation, and simultaneously accomplishes three critical objectives at ultra‐low applied potential (−0.125 V vs. RHE): nearly 100% conversion, 100% selectivity, and high FE of up to 98% (for 2 h). Joint experiments and theoretical calculations demonstrate that adjacent Ni‐Fe pairs electronically tune the neighboring Ni clusters, and the resulting synergy enables complementary functions of the two sites: Ni‐Fe pairs accelerate H 2 O dissociation, whereas Ni clusters regulate alkynol/alkenol adsorption for selective semi‐hydrogenation. The excellent stability, wide substrate universality, ultrahigh TOF, and low energy consumption of this low‐cost catalyst distinguish it from noble‐metal‐based systems with poor FE, offering a promising strategy for designing efficient polymorphic component catalysts.