Abstract: We are exploring the direct air capture of CO2 by mimicking crucial functions of single cell organisms that enable selective and kinetically efficient uptake under the small thermodynamic driving force created by low partial pressures of CO2 in the atmosphere. We hypothesize that by tuning the binding affinity of the amines of a CO2 capture solvent and functionalized electrodes, we can facilitate CO2 delivery to a redox site where it can be bound and transiently stored under a bias and easily released by a pH swing or removal of bias. Our current project strives to achieve this by utilizing a CO2 selective membrane (the ionone polymer membranes developed at U. Alabama to remove H2O, O2 and N2), kinetically coupled to a CO2 capture solvent (designed by PNNL) for enhanced uptake selectivity and favorable transport and an electrochemically generated transient site for strong binding and reversible conversion to carbonates/bicarbonates. We are taking a holistic approach to overcome the thermodynamic/kinetic limitations imposed by the low driving force for CO2 uptake, successively increasing CO2 sorption to create a free energy gradient to funnel CO2 towards a strongly binding electrochemically generated active site. Conversely, the extensive energy penalties for CO2 release can be mitigated by either electrochemical switching or a pH swing, the latter of which opens the potential for a high throughput flow system. In this presentation, an overview of the concept and our initial findings in the first year of funding will be presented.

Bio: Roger Rousseau is currently a group Leader and Lab Fellow at PNNL. He has an honors Bachelors in Science from the University of Windsor and a PHD in chemistry from the University of Michigan.