Integrated manufacturing of REciclable multi-material COmposites for the TRANSport sector

A bifunctional gas diffusion electrode is reported for integrated CO2 separation and electrochemical conversion to ethylene from low concentration CO2 stream (10 vol%), bypassing the prerequisite of energy?intensive incumbent CO2 capture and regeneration, compression, and transportation steps.The requirement of concentrated carbon dioxide (CO2) feedstock significantly limits the economic feasibility of electrochemical CO2 reduction (eCO2R) which often involves multiple intermediate processes, including CO2 capture, energy?intensive regeneration, compression, and transportation. Herein, a bifunctional gas diffusion electrode (BGDE) for separation and eCO2R from a low?concentration CO2 stream is reported. The BGDE is demonstrated for the selective production of ethylene (C2H4) by combining high?density?polyethylene?derived porous carbon (HPC) as a physisorbent with polycrystalline copper as a conversion catalyst. The BGDE shows substantial tolerance to 10 vol% CO2 exhibiting a Faradaic efficiency of ?45% toward C2H4 at a current density of 80 mA cm?2, outperforming previous reports that utilized such partial pressure (PCO2 = 0.1 atm and above) and unaltered polycrystalline copper. Molecular dynamics simulation and mixed gas permeability assessment reveal that such selective performance is ensured by high CO2 uptake of the microporous HPC as well as continuous desorption owing to the molecular diffusion and concentration gradient created by the binary flow of CO2 and nitrogen (CO2|N2) within the sorbent boundary. Based on detailed techno?economic analysis, it is concluded that this in situ process can be economically compelling by precluding the C2H4 production cost associated with the energy?intensive intermediate steps of the conventional decoupled process.

» Publication Date: 29/04/2023

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