Electrochemical CO2 conversion offers a direct route to decarbonized fuels, but its deployment on industrial flue gas remains hindered by the low CO2 content, high O2 levels, and the resulting parasitic oxygen reduction. Binary solvent electrolytes offer a lever to tune the local reaction environment under such dilute and impurity-rich conditions. Here we show a direct reactive capture (DRC) strategy that converts CO2 from dilute streams into CO with near-quantitative Faradaic efficiency in organic electrolytes under moderate pressure. We identify hydrogen-bond donation ability (HBD) as a decisive parameter governing competing hydrogen evolution and oxygen reduction reactions. Employing low-HBD electrolytes disrupts the hydrogen-bond network, suppresses competing reactions, and enables selective CO2 conversion even at 1% CO2 in the presence of O2. When fed with 15% CO2 and 8% O2 balanced with N2, the optimized system sustains >100 h operation with an energy consumption of 30.7 GJ ton−1 CO, and achieves a solar-to-fuel efficiency of ~5.5%. This impurity-tolerant strategy addresses a key barrier for industrial CO2 electrolysis and establishes a scalable route to solar-driven fuel production directly from flue gas. Electrochemical CO2 conversion from flue gas is hindered by low CO2 concentration and competing oxygen reduction. Here, the authors report the control over hydrogen-bond donation in binary organic electrolytes for selective CO production from O2-containing streams and suppressed side reactions.
Liu et al. (Tue,) studied this question.