A coupled electrochemical system for CO2 capture, conversion and product purification

Abstract

The efficient utilization of carbon dioxide (CO₂) as a resource, comprises three key processes: CO₂ capture, catalytic conversion and product purification. Using the renewable electricity to drive these processes provides a promising pathway for mitigating the ever-increasing atmospheric CO₂ concentration whilst simultaneously addressing the growing energy demand. Although each of the three individual processes has been extensively investigated during the past decade, the rapid and economically viable reduction of CO₂ emissions still calls for the development of an integrated electrochemical system driven by the renewable electricity to achieve carbon neutrality. Herein, we report a systematic protocol to bridge the three individual CO₂ utilization processes into one coupled electrochemical system: a bipolar membrane electrodialysis (BPMED) cell generating alkaline and acidic solutions for the capture and recovery of CO₂, a flow cell with an Ag gas diffusion electrode (GDE) for the selective electrocatalytic reduction of the recovered CO₂, and an alkaline solution container for the purification of the gaseous products and recycle of the unreacted CO₂. Consequently, the coupled electrochemical system successfully captured CO₂ from the simulated flue gas and converted it into a pure syngas stream.