Electrocatalytic upcycling of high-pressure captured CO2 to ethylene

Electrochemical upcycling of captured CO2 under high pressure holds significant potential to bridge between CO2 emissions and hydrocarbon commodities, yet it remains underexplored. Here we convert gas-phase high-pressure captured CO2 into ethylene (C2H4) 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 CO2 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 CO2, the system delivers industrial-grade 99.9% purity C2H4, creating an opportunity to turn the otherwise costly CO2 capture into a profit. Energy analysis suggests that directly valorizing high-pressure captured CO2, instead of depressurizing and repressurizing, is essential to minimize energy consumption. Electrocatalytic CO2 conversion offers opportunities for producing sustainable fuels and chemicals, but achieving strong performance with realistic CO2 sources remains a challenge. Here a system is designed to use high-pressure captured CO2, and achieves 85% Faradaic efficiency and high-purity C2H4 for over 1,500 h.