Coupling electrochemical CO₂ conversion with CO₂ capture

Abstract

Electrochemical CO₂ conversion into fuels or chemicals and CO₂ capture from point or dilute sources are two important processes to address the gigaton challenges in reducing greenhouse gas emissions. Both CO₂ capture and electrochemical CO₂ conversion are energy intensive, and synergistic coupling between the two processes can improve the energy efficiency of the system and reduce the cost of the reduced products, via eliminating the CO₂ transport and storage or eliminating the capture media regeneration and molecular CO₂ release. We consider three different levels to couple electrochemical CO₂ reduction with CO₂ capture: independent (Type-I), subsequent (Type-II) and fully integrated (Type-III) capture and conversion processes. We focus on Type-II and Type-III configurations and illustrate potential coupling routes of different capture media, which include amine-based solutions and direct carbamate reduction, redox active carriers, aqueous carbonate and bicarbonate solutions, ionic liquids CO₂ capture and conversion mediated by covalent organic frameworks.