Noble-Metal Nanocrystals in Metastable Phases

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With funding from the Macromolecular, Supramolecular & Nanochemistry Program of the Chemistry Division, Dr. Younan Xia of the Georgia Institute of Technology and Dr. Manos Mavrikakis of the University of Wisconsin-Madison will conduct fundamental research toward controlling the spatial arrangement (i.e. the crystal phase or structure) of atoms in nanocrystals. Such control could provide a versatile means of tailoring the electronic structure and catalytic properties of metal nanocrystals, opening the door to the development of advanced catalytic materials key to energy conversion and key for the production of important chemicals and pharmaceuticals. An important goal is to enable cost-effective and sustainable use of precious metals, some of the scarcest elements in the earth’s crust. The multi-disciplinary and collaborative nature of this project offers a natural vehicle to enrich the education and training experiences of all participants. The results from this project will be adapted to enhance classroom teaching, including the development of demonstrations (animations and experiments) related to key concepts in chemistry and chemical engineering. The investigators will promote diversity in higher education by engaging women, member of underserved groups in this research project. Specifically, Dr. Younan Xia and Dr. Manos Mavrikakis are developing colloidal methods for the synthesis of metal (e.g., ruthenium) nanocrystals in non-conventional, metastable crystal phases, together with well-controlled shapes or surface structures. These nanocrystals may open up avenues for observing new phenomena, enhancing existing processes, and enabling innovative applications. Currently, there are only a very limited number of reports on the synthesis of metal nanocrystals in metastable phases owing to the lack of a mechanistic understanding. Through an integration of experimental studies and computational modeling, the investigators seek to elucidate the trends and mechanisms involved in the synthesis, striving to establish experimental conditions for the reliable production of a specific crystal phase. The ruthenium nanocrystals will be used as seeds to template the deposition of other noble metals for the facile synthesis of core-shell nanocrystals featuring new, metastable crystal structures. In the context of structure-property relationships, the investigators will evaluate the catalytic activities of the metastable nanocrystals toward the oxygen evolution and oxygen reduction reactions.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.