CAREER:Elucidating Molecular Level Interplay Between Catalysts and Electrolytes in Electrochemical Reduction of CO2

University Of Delaware, Newark DE

Investigators

Abstract

The project addresses electrochemical reduction of the greenhouse gas carbon dioxide (ERCO2) - a critical step in sustainable strategies for generating fuels and commodity chemicals. More efficient and cost-effective routes for ERCO2 are needed for technological viability. In particular, interactions between the electrolyte and the electrocatalyst in ERCO2 cells are largely responsible for the overall performance of the system, yet are not well understood. The project addresses this need by employing a suite of advanced chemical characterization techniques to gain insight for the design of more effective polymer electrolytes and nanostructured catalysts. The project will also increase education and public awareness of the economic and environmental impact of electrochemical processes for converting CO2 to fuels and chemicals. A combination of in-situ surface-specific spectroscopic, electrokinetic, and isotope labeling techniques will be employed to elucidate the mechanism of the electrode surface-mediated ECRCO2 and its interplay with cations and anions in the electrolyte at the molecular level. Bicarbonate, the most commonly used anion in ECRCO2, is proposed to enhance the reaction rate by increasing the effective CO2 concentration at the electrode surface via the dynamic CO2-bicarbonate equilibrium. Moreover, electrostatically bound cations could reduce the access of reactants to the surface via site blocking at negative electrode potentials. Correlation between the structure of organic cations and the site blocking effect will be established. Insights gained in these mechanistic studies will be used in the design of polymer electrolytes for future ECRCO2 devices. Further, design principles for nanostructured catalysts with minimum transport limitation will be extracted by developing an experimental method to measure the pH, and in turn CO2 concentration, within 10 nm from the electrode surface in-situ. More broadly, special emphasis will be paid to attracting and retaining students from underrepresented groups in science, technology, engineering and mathematics (STEM) programs via a mobile device based software platform (the "GreenTech" app) to provide education and awareness of the need for sustainable and environmentally benign energy utilization.