High-Power CO₂-to-C₂ Electroreduction on Ga-Spaced, Square-like Cu Sites

The electrochemical conversion of CO₂ into multicarbon (C₂) products on Cu-based catalysts is strongly affected by the surface coverage of adsorbed CO (*CO) intermediates and the subsequent C-C coupling. However, the increased *CO coverage inevitably leads to strong *CO repulsion and a reduced C-C coupling efficiency, thus resulting in suboptimal CO₂-to-C₂ activity and selectivity, especially at ampere-level electrolysis current densities. Herein, we developed an atomically ordered Cu₉Ga₄ intermetallic compound consisting of Cu square-like binding sites interspaced by catalytically inert Ga atoms. Compared to Cu(100) previously known with a high C₂ selectivity, the Ga-spaced, square-like Cu sites presented an elongated Cu-Cu distance that allowed to reduce *CO repulsion and increased *CO coverage simultaneously, thus endowing more efficient C-C coupling to C₂ products than Cu(100) and Cu(111). The Cu₉Ga₄ catalyst exhibited an outstanding CO₂-to-C₂ electroreduction, with a peak C₂ partial current density of 1207 mA cm^-2 and a corresponding Faradaic efficiency of 71%. Moreover, the Cu₉Ga₄ catalyst demonstrated a high-power (∼200 W) electrolysis capability with excellent electrochemical stability.