Engineering CObridge adsorption in Cu(II)/Cu(I) interfaces modulated by ionic liquid for enhanced CO2 electroreduction to ethylene

Electrochemical CO 2 reduction to highly selective ethylene is particularly desirable yet challenging. The competition between methane and ethylene in the CO 2 RR process underscores the critical necessity of designing the catalyst for ethylene by suppressing the methane pathway. Herein, we introduced controllable Cu(II)/Cu(I) interfaces by regulating the ratio of ionic liquids (ILs) and H 2 O. The Cu x O-IL4 catalyst with main CuO/Cu 2 O structure, exhibits a high Faraday efficiency toward C 2 H 4 (∼54 %) and less CH 4 (∼1 %) under 250 mA·cm −2 current density at −1.18 V (vs RHE). Experimental and theoretical analyses demonstrate that Cu(I) sites favor CO bridge formation, while Cu(II) sites preferentially generate CO atop on Cu x O-IL4 catalysts. The Cu(II)/Cu(I) interface in Cu x O-IL4 facilitates the generation of CO bridge intermediates, thereby lowering the energy barrier for *CO dimerization and also preventing *CO hydrogenation to CH 4 formation, thus enhancing the selectivity of CO 2 -to-ethylene conversion. The study provides a novel approach for precisely controlling CO adsorption configurations to enhance CO 2 RR selectivity toward high-value multicarbon products formation.