Hydrophobic, Ultrastable Cu⁺ for Robust CO₂ Electroreduction to C₂ Products at Ampere-Current Levels

Copper (Cu) is the only known material that can efficientlyelectrocatalyzeCO(2) to value-added multicarbon products. Owing to the instabilityof the Cu delta+ state and microscopic structure in reactions,Cu catalysts are still facing big challenges with low selectivityand poor durability, particularly at high current densities. Herein,we report a rational one-step surface coordination approach for thesynthesis of Cu dendrites with an ultrastable Cu delta+ state and hydrophobicity (Cu CF), even after exposure to air forover 6 months. As a result, Cu CF exhibited a C-2 FE of90.6% at a partial current density of 453.3 mA cm(-2) in a flow cell. A 400 h stable electrolysis at 800 mA and even aground-breaking stable operation at a large industrial current of10 A were achieved in the membrane electrode assembly (MEA) form.We further demonstrated a continuous production of C2H5OH solution with 90% relative purity at 600 mA over 50 h ina solid-electrolyte reactor. Spectroscopy and computation resultssuggested that Cu-(II) carboxylate coordination species formed on thesurface of Cu CF, which ensured the stability of the Cu delta+ state and hydrophobicity. As a result, rich active sites and a stablethree-phase interface on the catalyst surface were achieved, alongwith the optimized *CO adsorption strength and adsorption configuration.The mixed *CO adsorption configurations on Cu CF made the *CO dimerizationprocess easier, which promoted the conversion of CO2 toC(2) products. This work provides a promising paradigm forthe design and development of Cu-based catalysts with ultrahigh stabilityunder industrial current densities.