CAREER: Freeze-frame Spectroscopy, a technique for elucidation of fundamental interactions underlying nanocatalytic reactions

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This CAREER award by the Chemical Catalysis Program of the Chemistry Division supports the work of Professor David T. Moore of Lehigh University to develop freeze-frame spectroscopy (FFS), an experimental method to directly probe interactions of reactant molecules with nanocatalysts. Freeze-frame spectroscopy is explicitly designed to stabilize the pre-reactive complexes of interest in cryogenic matrices so that they may be structurally characterized using vibrational spectroscopy. The high-resolution afforded by this matrix-isolated spectroscopic technique allows detection of the characteristic shifts in vibrational bands associated with the interaction of the reactant molecules and the catalyst material. The FFS approach also explores nanocatalytic reaction pathways. Resonant laser pumping is used to rapidly deposit energy into the stabilized pre-reactive complexes so that they can cross activation barriers to form reactive intermediates or product complexes that are then trapped and characterized. Professor Moore's research focuses on carbon monoxide (CO) oxidation on gold nanoparticles in order to better understand how trends in nanoparticles size and charge correlate to trends in reactivity. Laser pumping experiments are carried out at the free-electron laser facility (FELIX) in Nieuwegein, Netherlands, in order to verify the pre-reactive nature of the detected complexes and to further characterize the potential energy surfaces of the catalytic reaction pathways. A new partnership with South Mountain College has been developed to provide immersive learning experiences in scientific research to non-science majors.This CAREER award by the Chemical Catalysis Program of the Chemistry Division supports the work of Professor David T. Moore of Lehigh University to develop freeze-frame spectroscopy (FFS), an experimental method which looks at interactions between reactant molecules and nanometer-sized catalysts. Catalysts are used to increase the speed of chemical reactions. Direct examinations of reactant-catalyst complexes are rarely possible because good catalysts do not bind reactants very strongly or for very long. FFS overcomes this hurdle by using very low temperatures to slow the catalytic reactions and then employing light to take a "snapshot" of the reactant-catalyst interaction. The FFS experiments are verified by additional laser studies conducted in the Netherlands. Professor Moore's graduate students travel to Nieuwegein to perform these measurements and to gain an appreciation for international culture. Initials studies examine the catalytic oxidation of carbon monoxide (CO) by oxygen (O2) on gold nanoparticles. This reaction has relevance in the alternative energy arena, since CO is a potent poison for the catalysts used in hydrogen fuel cells. The broader impacts of this work include the development of new methods for teaching science to humanities and social science majors within the liberal arts curriculum. Instructors will work with students to develop short, focused research projects with relevance to the students' primary areas of interest. These projects provide the undergraduates with insight into vital aspects of the scientific method.