2025 AIChE Annual Meeting

(119e) Theoretical Study of Electrocatalytic Nitrate Reduction on Dilute Atom Alloys

Author

Kasun Gunasooriya - Presenter, Technical University of Denmark
Nitrate (NO3−) pollution of aquatic ecosystems and drinking water disrupts the global nitrogen cycle and poses a significant threat to human health and the environment, which has been labeled as a grand challenge by the National Academy of Engineering. Electrocatalytic nitrate reduction (NO3RR) is a promising way to remove nitrate from contaminated groundwater due to the use of renewable electricity, reduction of waste, and production of value-added products. NO3RR converts nitrate ions in water to benign or valuable products, such as nitrogen gas, ammonia, hydroxylamine, or ammonium nitrate. The rate of conversion and selectivity towards each product depends on a complex reaction mechanism involving many surface reaction intermediates. Previous and recent studies have been primarily focused on pure transition metals and identified initial NO3− reduction to nitrite (NO2−) as the rate-determining step. Recently, dilute atom alloy (DAA) catalysts consisting of catalytically active metal atoms atomically dispersed in a second, typically more inert, host metal, have attracted increasing attention due to their atom-utilization efficiency and superior catalytic performance. In this work, we evaluated NO3RR performance on single and dual-atom alloys in Ag(111), Cu(111), and Au(111) hosts. Our calculations identified a selected number of DAAs that catalyze NO3RR while inhibiting hydrogen evolution reaction (HER). We further developed a mean-field microkinetic model to gain key mechanistic insights. Finally, we established rational catalyst design principles for next-generation NO3RR.