Continuous Gas-to-Liquid Conversion for Carbon-Efficient Electroreduction of CO2

Addressing climate change necessitates scalable Carbon Capture, Utilization, and Storage (CCUS) technologies including the efficient electrochemical CO2 reduction process. This study unveils a novel CO2 electrolysis system optimized for continuous gas-to-liquid electroreduction of CO2. Unlike traditional single-pass systems, the devised setup circulates CO2 gas for multiple passes through the cathode, bolstering carbon-conversion efficiencies (CCEs) and enriching product concentrations in the flowing electrolyte. Two operational modes were studied, with the “regeneration” mode activated upon byproduct accumulation, leading to an increase of CO2 concentration inside the gas loop. This mode oxidizes H2 and CO for energy and carbon recovery, eliminating the need for additional gas separation processes, thereby enhancing the practicality and economic viability of distributed carbon utilization systems. Remarkably, a 312-hour continuous operation was demonstrated with >90% carbon efficiency, underscoring the system's robustness and long-term operational stability. Continuous conversion of CO2 to formate, a versatile industrial chemical, further accentuates the potential of this system in advancing carbon-neutral or carbon-negative chemical and fuel production, marking a significant stride towards the practical deployment of CCUS technologies.