Bridge‐Evolution in Heteronuclear Clusters Triggers Atomically Precise Alloy Heterojunctions for Electrocatalytic Ethanol Oxidation

ABSTRACT Conventional single‐source precursors for electrocatalysts lack tailored topological features and adjustable bridge species, failing to directionally induce the formation of specific heterojunctions. To address these challenges, a heteronuclear cluster [(Co 8 Ni 1 )( µ 4– Cl)(H 3 L 1 ) 8 Cl] with a windmill‐like topological structure is designed, and its pyrolytic catalyst is first discovered to exhibit excellent catalytic proficiency for the electrochemical oxidation of ethanol. X‐ray absorption spectroscopy combined with thermogravimetry–mass spectrometry reveals the pyrolysis‐induced evolution of the central µ 4 –Cl bridge toward a more thermodynamically favored µ 4 –O coordination environment, which promotes coordination vacancies and facilitates the in situ formation of CoNi/CoO alloy heterojunctions. As expected, the prepared Co 8 Ni 1 ‐700 catalyst exhibits excellent bifunctional electrocatalytic activity: for EOR (1.396 V vs. RHE with acetate selectivity exceeding 90%), for HER (53 mV), and AEMWE (2.089 V and stably operating for 400 h). Density functional theory calculations indicate that the CoNi/CoO heterointerface strengthens ethanol adsorption relative to isolated CoO or CoNi phases and lowers the reaction barrier for EOR intermediates. The novel cluster and its bridge evolution mechanism developed in our work establish an innovative conceptual framework for engineering atomically controllable heterojunction multifunctional electrocatalysts.