Fastening Br– Ions at Copper–Molecule Interface Enables Highly Efficient Electroreduction of CO₂ to Ethanol

Developing advanced electrocatalysts to convert CO 2 into liquid fuels such as ethanol is critical for utilizing intermittent renewable energy. The formation of ethanol, however, is generally less favored compared with the other hydrocarbon products from Cu-based electrocatalysts. Herein, we construct an efficient electrocatalyst for ethanol formation based on dodecanethiol-modified CuBr, which in situ generates a robust Br-doped Cu–thiol interface. The obtained electrocatalyst shows a significantly enhanced C2+ Faradaic efficiency of 72%, among which the Faradaic efficiency of ethanol is 35.9%. Notably, the ratio of ethanol to ethylene significantly increases from 0.32 for pristine CuBr to 1.08 for dodecanethiol-modified CuBr. The improved electrocatalytic activity is related to the modulated adsorption energy of key intermediates on the Br-doped Cu–thiol interface as verified by density functional theory (DFT) calculations. The present study highlights the great potential of utilizing hybrid metal–molecule interfaces for improving electrocatalytic CO 2 conversion.