Continuous Capture and Reduction of CO2 in an Electrochemical Molten-Salt System with High Efficiency

Electrochemical reduction of carbon dioxide (CO2) into high-value fuels has been considered as a promising and economic method to mitigate the global warming issue. However, it is still a challenge to realize the simultaneous capture and conversion of CO2 in an efficient way, which is essential for direct applications in high-carbon-emission plants. Herein, we demonstrate the novel design of a molten-salt-based electrolyzer featured with partitioned electrolysis chambers, which can continuously capture and convert CO2 into CH4 with 100% conversion efficiency. Systematic studies are conducted based on this electrolyzer to boost the CH4 production, including the composition tuning of Li-Na-K ternary eutectic carbonates as the electrolyte, the choice of anode and cathode electrocatalysts, and the optimization of electrochemical parameters (i.e., the current density, temperature, and CO2 flow rate). The highest selectivity of methane (33.26%) is obtained at 400 mA<middle dot>cm(-2) using a commercial cupronickel (CuNi18) sheet as the cathode and a corrosion-resistant nickel (Ni) sheet as the anode in the molten Li1.427Na0.359K0.214CO3 similar to 0.15LiOH at 650 degrees C. This work could provide a feasible and efficient strategy toward the development of integrated CO2 capture and utilization techniques..