Direct oxygen-containing simulated flue gas electrolysis over amine-confined Ag catalyst in a flow cell

High cost of pure CO2 feed constitutes a significant economic obstacle in industrial-scale CO2 electrolysis. Direct CO2 electrochemical conversion from flue gas has emerged as a promising strategy to reduce feed cost, while the O2 in flue gas cannot be ignored due to its strong reactivity. Here, we achieved fast, selective CO electrosynthesis directly fed with simulated oxygen-containing flue gas (95% CO2+5% O2) over the amine-confined Ag catalysts in a flow cell, among which dimethylamine-modified Ag exhibited 80.6% CO Faradaic efficiency with partial current density of 333.7 mA cm−2. In situ spectroscopy demonstrated that dimethylamine confinement endows a robust CO2 adsorption-conversion capacity. Theoretical calculations further elucidated that amine modification could not only mediate CO2 adsorption and ∗COOH intermediate formation but could also block the ∗OOH intermediate pathway in the side reaction of oxygen reduction. These findings pave a new avenue for rational design of amine-confined electrocatalysts for direct flue gas conversion and utilization.