Discipline: Chemistry and Chemical Sciences
Subcategory: Chemistry (not Biochemistry)
Room: Park Tower 8209
Jacob M. Garcia - Arizona State University
Co-Author(s): Ryan Shaffer, and Scott G. Sayres, Arizona State University, Tempe, AZ
Environmental, economic, and societal concerns over energy and fuels continue to drive the need for catalysts of increased reactivity and decreased negative impact. Molecular clusters have gained increased attention due to their ability to model bulk materials, ease of production, and high reactivity. Iron oxides have been used in a multitude of different essential industrial techniques including the production of ammonia via the Haber-bosh process, synthesis of molecular hydrogen via the water-gas shift reaction, and numerous medical uses. Recently, the catalytic oxidation of CO and the dehydrogenation of methanol using iron oxide clusters have been experimentally studied, but have not identified critical intermediate steps in a complex catalytic process. Using laser ablation in tandem with femtosecond pump-probe spectroscopy, the gas-phase reactions of iron oxide clusters with gases of industrial or environmental interest can be elucidated. Using 400/800 nm pump-probe laser pulses, we have observed the excitation-relaxation dynamics of neutral iron clusters in the presence of oxygen gas. A current trend of decreased relaxation time of the 1:1 stoichiometry in neutral iron clusters from (FeO)n (n = 1-10) has been observed. This ability to stabilize electronic stimuli may be due to an induced caging effect from atomic oxygen. Interestingly, there is also a fast decay in the (FeO)6O molecule, which is quicker than any other FenOm neutral observed. Current experiments look to elucidate the precise molecular binding and time-resolved excitation-relaxation, and dissociative properties of neutral iron oxides with industrially relevant molecules such as CO and CO2. The information gained will provide a more comprehensive understanding of future catalysts, creating materials of increased reactivity and decreased impact.
References: 1) Schlogl, Robert. ngew. Chem. Int. Ed. 2003, 42, 2004-8. 2) Rhodes, C.; Hutchings, G. J.; and Ward, A. M. Catalysis Today. 1995, 23, 43-58. 3) Jones, N. O.; Reddy, B. V.; Rasouli, F.; and Khanna, Shiv N. Phys. Rev. B. 2005, 72, 165411-4. 4) Xue, Wei; Wang, Zhe-Chen; et al. J. Am. Chem. Soc. 2008, 130, 15879-88. 5) Xie, Yan; Dong, Feng; Heinbuch, Scott; Rocca, Jorge J. and Bernstein, Elliot R. J. Chem. Phys. 2009, 130, 114306-11.
Funder Acknowledgement(s): This research was supported in part by the Western Alliance to Expand Student Opportunities (WAESO) Louis Stokes Alliance for Minority Participation (LSAMP) Bridge to Doctorate (BD) National Science Foundation (NSF) Grant No. HRD-1702083.
Faculty Advisor: Scott G. Sayres, firstname.lastname@example.org
Role: I have conducted all parts of this research, from construction to data analysis.