Metal Oxynitrides: Tuning Metal-N and Metal-O Interactions for Improved Electrocatalytic Properties at the Liquid/Solid Interface

University Of North Texas, Denton TX

Investigators

Abstract

Non-technical Summary Ammonia production is vital to agriculture but is currently produced by an energy-intensive process that also produces significant amounts of CO2. Earth-abundant transition metal oxides and oxynitrides are the primary materials used as catalysts for synthesis of ammonia from dinitrogen, which comprises 78% of Earth’s atmosphere. Widespread use of these materials for such technologically important applications poses a significant challenge, however, as the atomic-level understanding of oxynitride surface chemistry at the complex electrolyte/solid interface is not well understood. With this project, supported by the Solid State and Materials Chemistry and Ceramics programs in the Division of Materials Research, Profs. Cundari, D’Souza and Kelber and their research groups at the University of North Texas (UNT) will investigate fundamental chemical interactions relevant to the conversion of dinitrogen to ammonia via more energy-efficient routes. The studies will help in understanding the chemical and material factors that are most important for optimizing new materials for ammonia production from dinitrogen, and applications to other important industrial reactions. Involved student researchers will learn a wide range of experimental and computational skills and the PIs will collaborate with other UNT faculty and students to develop brief presentations – in English and Spanish – on important chemistry topics to heighten interest of high school students in pursing Chemistry and other STEM careers. Technical Summary The production of NH3 from N2 relies on the high temperature Haber-Bosch process which consumes much energy and produces significant CO2 and the design of new materials to provide an environmentally/energetically friendly alternative to produce N2 can have significant impact on agriculture, energy saving, and the environment. Earth-abundant transition metal oxides and oxynitrides are rapidly growing in interest for energy and environmental applications, but the fundamental roles of N, O and metal centers in N2 reduction are, however, not well understood. This project, supported by the Solid State and Materials Chemistry and Ceramics programs in the Division of Materials Research, will investigate fundamental interactions at the electrolyte/solid interface relevant to the reduction of dinitrogen to ammonia, and to other electrocatalytic processes, such as the formation of hydrogen and oxygen. Electrochemical methods, combined with in situ and operando surface science probes, will probe the fundamental interactions at the electrolyte/oxynitride interface governing both catalytic efficiency and selectivity. Experimental studies will be both supported and guided by theoretical efforts focused on the energetics of reaction pathways at N-supported vs. O-supported metal centers. Students involved will learn both experimental and theoretical methods, which will enhance their capabilities in both academic and industrial research environments. 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.