CAREER: Tuning Interfacial Ion Assembly to Engineer Electrochemical Reactions for a Sustainable Future

University Of Wisconsin-Madison, Madison WI

Investigators

Abstract

Electrochemical devices play a critical role in lowering carbon emissions in the energy and chemical sectors. These devices are typically composed of two electrodes joined by an electrolyte. While significant research has focused on the effect and evolution of electrodes during device operation, a detailed understanding of the role of electrolytes remains unresolved. Carbon dioxide (CO2) reduction reactions are energy-intensive and must compete with undesirable parasitic reactions which reduce both energy and carbon efficiency. There is a pressing need for new ways to tune electrolytes for the selective conversion of CO2 to carbon monoxide (CO), a key specialty chemical that can be used to make a wide range of chemical products. This project aims to explore how ion self-assembly in electrolytes at interfaces could revolutionize the performance of CO2 electrocatalysis into chemical feedstocks to mitigate the carbon footprint of chemical production. The project addresses how the self-assembly of organic ions promotes electrocatalytic reactions and connects these insights to reaction mechanisms and interfacial properties. This research will provide the fundamental basis for molecular level design of electrolytes that will advance technologies needed to address key sustainability challenges, such as CO2 recycling. Further, this project aims to catalyze growth of a diverse domestic STEM workforce by launching educational programs, including an Electrocatalysis Workshop for high school teachers and a public Water Splitting Challenge. Educational activities aim to foster an inclusive workforce in electrochemistry. The objective of this project is to understand how collective ion assembly influences electrochemical properties and electron transfer at interfaces. CO2 reduction in ionic liquid electrolytes will be used as a model system, since ionic liquids provide opportunities to tune interfacial properties and catalytic reactivity via molecular assembly. The driving hypothesis is that electrocatalytic reactivity is dictated by electric field strengths immediately adjacent to electrode surfaces in a region where ions assemble, called the electric double layer. Further, this project aims to study how electric field strengths can be enhanced by modulating collective ion assembly, which will accelerate reactions involving polar intermediates, such as CO2 reduction. The key objectives are: (1) understand how collective ion assembly influences CO2 reduction, (2) reveal how ion assembly governs electrochemical properties of interfaces, and (3) study how ion aggregation can confine co-ions at interfaces to tune reactivity. The research will bridge catalysis science with a unique set of surface forces and spectroscopy tools to determine how structural, chemical, and electrochemical properties intersect to govern electrocatalytic reactions. By systematically studying how ion molecular structures influence assembly and electrochemical reactivity, this project promises to develop mechanistic insights into how interfacial microenvironments can be influenced at the molecular level to address growing challenges in sustainable energy and chemical manufacturing. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.