(Invited) Challenges and Opportunities in the Integration of CO2 Capture and Conversion

Abstract

Over the past 15 years or so, the electroreduction of CO2 for the synthesis of intermediates for the chemical industry as well as for the synthesis of small molecule fuels has become a very active area of research. Activities span the whole value chain from electro-catalyst synthesis and characterization, to electrode and cell design and optimization, as well as studies on techno-economic feasibility and life cycle assessment of envisioned overall processes. In the vast majority of these studies, >98% pure CO2 is being used as the feed. In reality, CO2 feeds captured from industrial flue gasses or even those captured from air may not be close to 100% in CO2.This presentation will explore the integration of a nanomembrane-based CO2 capture method with different CO2 electrolysis approaches. The nano-membrane-based CO2 capture is based on work by Fujikawa and Selyanchyn (Polymer J. 2021, 53, 111), using polydimethylsiloxane-derived membranes that are preferentially permeable to CO2 over nitrogen. Multistage arrangement of modules comprised of arrays of membranes allows for efficient concentration of CO2 from air, from 420 ppm to tens of percent, using just vacuum pumps to drive the process. We explore the use of these concentrated CO2 streams that still contain nitrogen and some oxygen as the feed in subsequent CO2 electrolysis conversions to CO, to methane, or to other products, depending on catalyst choice. We study the effects of feed composition, catalyst chosen, and cell configuration on product speciation, conversion efficiency, etc.