(232h) Process Intensification for Electrochemical Utilization of CO2 | AIChE

(232h) Process Intensification for Electrochemical Utilization of CO2


Liu, K., University of Kentucky
Thompson, J., University of Kentucky
Conversion of anthropogenic CO2 emissions to useful chemical fuels or feedstocks is a desirable strategy for reducing atmospheric CO2 concentration. Formic acid is a diverse product currently used in the textile and agricultural sectors, as well as a component in cleaning products and preservatives. Formic acid is also valuable as chemical fuel, a potential liquid H2 carrier in the “centralized de-carbon economy”. Production of formic acid with intermittent renewable energy sources would allow for excess energy produced during low demand load to be stored and used during peak load times, while also reducing CO2 emissions. Progress toward the development of an electrochemical “one-step” CO2 utilization process to produce formic acid will be discussed. The proposed CAER-ECUS process combines three previously developed components, a protective redox hydrogel, a CO2 reducing catalyst, and the CAER proprietary Xerogel® electrode, to synthesize formic acid directly from CO2 in a flexible process that can be modified based on changing economics and market conditions. These three key components work in concert to make the CAER-ECUS process a potentially disruptive technology by: 1) directly producing a viable and flexible chemical feedstock that can be sold or used for energy storage, 2) protecting valuable catalyst against deactivation by overpotentials and faradaic inefficiencies from the electrode or oxidation from flue gas contaminants, and 3) preforming the reaction on a large surface area (> 200 m2/g) electrode with large pore structures reduce mass transport issues. We show that the redox-active hydrogel increases electrochemically-active surface area, and that the effective charge carrier has a redox potential within the desirable range for CO2 reduction. Hydrogel properties, catalyst selection, process design and integration, as well as future directions for the CAER-ECUS process will we discussed.