(Invited) Design, Assessment, and Performance Evaluation of an Fully-Integrated Electrochemical Process for Direct Capture of CO2 from Flue Gas and Its Conversion to High-Purity Ethylene

Abstract

Ethylene (C2H4) is a hydrocarbon of extensive societal, environmental, and industrial importance. Therefore, synthesizing C2H4 sustainably via the electrochemical CO2 reduction reaction (CO2RR) is an attractive area to explore. Even though many existing CO2RR systems have reached industrially relevant current densities (~1A/cm^2), almost all use a gas diffusion electrode (GDE)-based electrochemical system with a single-pass CO2 conversions less than 10%. Low conversion leads to a low C2H4 concentration in the gaseous product stream which mainly comprises CO2, contributing to costly post-CO2RR separation of products, rendering even processes with high CO2RR current densities unfit for scale up. In this talk, I will present an automated and fully-integrated system that combines CO2 capture and conversion into a single, sustainable, and more energy-efficient process. In particular, our technology captures CO2 from the exhaust of natural-gas combustion power plants and converts it to high-purity ethylene. The patented CO2 capture process utilizes novel migration-assisted moisture gradient (MAMG) process, with record performances of over 99% selectivity and over 0.3 mmol/m2s of capture flux. Our team has recently discovered electrocatalysts based on mixed Cu/CuOx with performance far exceeding state-of-the-art catalysts for CO2 conversion with 600 mA cm-2 and Faradaic efficiency to C2H4 over 58%. The system will be scaled up as a supplementary process to existing C2H4 production plants or for inclusion in new plants meeting carbon intensity reduction targets.