CAREER: Surface-Inspired Catalysis via an Updated Cluster-Surface Analogy

University Of Pennsylvania, Philadelphia PA

Investigators

Abstract

Supported by the Chemical Catalysis (CAT) Program in the Division of Chemistry, Professor Neil Tomson of the University of Pennsylvania is developing new chemical routes to make transportation fuels. Transportation accounts for one-quarter of all energy use in the United States. Most transportation fuel comes from petroleum. This project targets fuels from renewable sources that adapt well with current infrastructure. One objective focuses on combining hydrogen with nitrogen to give ammonia, a potentially new "energy storage media". A second project examines new pathways from carbon dioxide (CO2, an industrial waste product) to hydrocarbons. Current methods for such chemical reactions are expensive; to potentially reduce the cost of fuel production from CO2 this research emphasizes the design of new catalysts. These new catalysts feature pairs of metals in a manner that resembles bulk metal catalysts. These particular geometries facilitate the bond making and bond breaking steps required for producing the fuels. Students working on this project gain hands-on experience on advanced chemical synthesis and catalyst evaluation. The young researchers are also trained to communicate scientific results to a broad audience. This training involves lectures as well as the production of videos aimed at high school students. The target audiences include those underserved by traditional educational venues and underrepresented in the STEM disciplines. As of 2018, 92% of the energy used by the transportation sector came from petroleum mining. The anticipated depletion of this resource, along with shifting environmental and national security concerns, motivates the development of fuels that are both derived from renewable resources and compatible with the nation’s existing energy infrastructure. In this project, supported by the Chemical Catalysis Program in the Division of Chemistry, Professor Neil Tomson of the University of Pennsylvania, investigates new catalysts to synthesize ammonia and alkanes. Although solar hydrogen is becoming increasingly available, methods for performing low-energy hydrogenations of small feedstock chemicals remain underdeveloped. Professor Tomson's research is targeting two processes that are likely to be critical for the future energy economy. The first process aims at dehydrogenation of ammonia. The second, but related process, aims to generate hydrocarbons from synthesis gas. The research draws inspiration from heterogeneous catalysis, especially those utilizing metallic surfaces. The new catalysts incorporate electronic and geometric flexibility, which may emulate key characteristics of metallic surfaces. In preliminary experiments, the new catalysts have been shown to stabilize a wide range of intermediates previously proposed for the Mittasch and Fischer-Tropsch catalysts. Finally, this project’s focus on mitigating the nation’s reliance on fossil fuels highlights a need for scientists of the future to be able to think creatively outside their immediate discipline. By reaching high school, undergraduate, and graduate students, including many from minority populations that are underrepresented in the STEM disciplines, the project endeavors to inspire the next generation of scientists, while aiding in the development of the metacognitive skill sets that are known to be critical to this cross-cutting creativity. 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.