CAREER: Engineering Electrolytes and Active Sites for Efficient Nitrogen Cycle Electrocatalysis

Nitrate is an ion composed of nitrogen and oxygen that is used in agricultural and industrial processes. Nitrate accumulation in water poses a serious threat to ecosystems and human health. A promising solution uses electricity to convert nitrate into chemical products. The conversion involves catalytic reactions at the surface of an electrode. Current technologies for nitrate conversion are inefficient because multiple reactions occur at once and processes at the electrode surface are not well understood. This project will find new ways to study reactions at the electrode surface and improve nitrate conversion. The results will help new developments for water treatment and chemical manufacturing. The project will engage high-school and undergraduate students in hands-on research and design-based learning that will stimulate interest in STEM careers. Electrocatalytic nitrate reduction and competing hydrogen evolution collectively involve a complex reaction network that is strongly influenced by catalyst structure and the surrounding solution environment. This project will combine quantitative kinetic analysis with time-resolved operando infrared spectroscopy to identify key surface intermediates and solvent structures during catalysis. Kinetic models that account for non-ideal electrolyte behavior will be used to quantify how electrolyte composition modifies the energetics of kinetically relevant elementary steps. These insights into the mechanisms of nitrate reduction and hydrogen evolution will enable designing new electrolyte formulations and catalysts that improve efficiency and selectivity to desired products. The project will establish broadly applicable strategies for linking interfacial structure, solvation, and reactivity in electrocatalysis, with relevance to a wide range of electrochemical reactions beyond nitrate conversion. 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.