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 CO 2 reduction (CO 2 R) using dilute CO 2 concentrations (5-15%), which offers a sustainable pathway to convert waste CO 2 into fuels and chemicals. However, dilute CO 2 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 CO 2 availability, steering the CO 2 R 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 CO 2 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 CO 2 R.