Interfacial engineering strategies and sustainability assessment for direct electrolysis of dilute CO₂ streams

The continuous decreasing in the levelized cost of renewable electricity has promoted the accelerated development of electrocatalysis, particularly electrochemical CO₂ reduction (CO₂R) using dilute CO₂ concentrations (5-15%), which offers a sustainable pathway to convert waste CO₂ into fuels and chemicals. However, dilute CO₂ introduces substantial concentration overpotentials, leading to unsatisfactory selectivity and energy efficiency. Here, we develop effective approaches (pH control, amine addition, gas compression) to enrich the interfacial CO₂ availability, steering the CO₂R selectivity towards the desired products. We further conduct techno-economic analysis and cradle-to-gate life cycle assessments to evaluate their economic and environmental performance. For instance, HCOOH production cost drops from 1.11 to 0.47 $ kg^-1, lower than the 0.58 $ kg^-1 of the pure CO₂ scenario. Moreover, environmental burdens such as climate change and cumulative energy demand decrease by 38.2%-72.0% relative to the flue-gas scenario without these strategies. Overall, although variations in the electricity mix influence the absolute values reported in this study, our work provides critical implications and design principles for dilute CO₂R.