Electrocatalytic upcycling of high-pressure captured CO2 to ethylene

Electrochemical upcycling of captured CO 2 under high pressure holds significant potential to bridge between CO 2 emissions and hydrocarbon commodities, yet it remains underexplored. Here we convert gas-phase high-pressure captured CO 2 into ethylene (C 2 H 4 ) using a high-pressure membrane electrode assembly equipped with In/Cu catalysts, affording up to 85% Faradaic efficiency and 750 mA cm −2 partial current density under 20 bar. Theoretical calculations and operando studies link enhanced C–C coupling to the pressure-modulated *CO adsorption configuration and elevated CO 2 coverage. High pressure also mitigates salt precipitation by relocating bicarbonate formation to the catalyst–membrane interface, enabling stable electrolysis for over 1,500 h at 600 mA cm −2 . As a proof of concept, by recapturing residual CO 2 , the system delivers industrial-grade 99.9% purity C 2 H 4 , creating an opportunity to turn the otherwise costly CO 2 capture into a profit. Energy analysis suggests that directly valorizing high-pressure captured CO 2 , instead of depressurizing and repressurizing, is essential to minimize energy consumption.