(6bh) Elucidating Atomic Dances through Reaction Landscapes

The vision of my research group will be the discovery and elucidation of relationships between catalysts and the reactions they catalyze. How do atoms come together and why do they come together the way they do? Transformation of molecules is at the core of energy and environmental chemistry. An understanding of how they transform at the atomic level accelerates progress in catalyst development. Research projects will be chosen due to environmental impact, industrial importance, and potential for the ideas and theories of the chemistry to be generalized and applicable across disciplines. My research group will collaborate with other research groups whose expertise deviates from our own - for instance, with computational groups and synchrotron facilities at national laboratories. Themes my research group will focus on are:

• Discovery of active sites and Elucidation of catalytic mechanisms at the atomic level
• Design and Validation of in-situ and operando reactors

PhD Research: (Purdue University, School of Chemical Engineering, Advisor: Fabio H. Ribeiro)

“Synthesis and Characterization of Copper-Exchanged Zeolite Catalysts and Kinetic Studies on NO_x Selective Catalytic Reduction (SCR) with Ammonia”

My PhD research involved unraveling atomic details of the mechanism for model Cu-SSZ-13 zeolite solids to reduce NO_x from diesel engine exhaust with NH₃ and O₂ to environmentally benign H₂Oand N₂ at 200°C. This research involved collaboration with computational groups (Schneider Group from the University of Notre Dame and Greeley Group at the Purdue University), industrial partners (Cummins Incorporated), Argonne National Laboratory, and international partners (Universidad de Antioquia, Colombia). Both experimental and computational groups paved the road to discovery. We first determined from kinetic and spectroscopic evidence that precursors to the active sites were Cu²⁺ ions, and that even though the material is a solid catalyzing a gas phase-reaction, the Cu²⁺ behaves as if it is on a leash in a liquid solution. Additional quantitative spectroscopy, titration experiments, and density functional theory (DFT) computation presence of two types of active Cu²⁺, namely bare Cu²⁺ and (CuOH)¹⁺. Computational insight in addition to operando, in-situ, and ex-situ x-ray absorption spectroscopy (XAS) experiments at the Advanced Photon Source at Argonne National Laboratory gave oxidation-state and coordination information, which were used to piece together how these active Cu²⁺catalyzed the reaction.

Postdoctoral Research: (Leiden University, Leiden Institute of Chemistry, Advisor: Marc T.M. Koper)

“Understanding Atomistic Details of the Hydrogen Evolution Reaction (HER) on Pt(111) and Graphene/Pt(111) in H₂SO₄”

My postdoctoral research involves unraveling atomic details for the mechanism of the hydrogen evolution reaction (HER) in aqueous H₂SO₄ on Pt(111) and Graphene/Pt(111) electrodes under ambient temperatures and pressures. A monolayer of graphene was grown on a Pt(111) surface using chemical vapor deposition (CVD) and characterized using scanning electron microscopy (SEM) and Raman spectroscopy. Cyclic Voltammogram (CV) sweeps indicated that the graphene monolayer is selectively permeable to H⁺ ions in the electrolyte, allowing only H⁺ ions into the confined layer between Pt(111) and graphene. The impact of this confinement on the HER mechanism was probed using reaction kinetics (rates, Tafel slopes, reaction orders).

During my postdoc, I refined my skillset in collecting kinetics in both gaseous and aqueous systems and contemplated differences in the theories between thermal-activated and electron-activated catalysis. In both my PhD and postdoctoral research, probing and understanding how flow of electrons affected the local active site environment and vice versa under catalytic conditions was essential in rationally piecing together mechanistic details.

Teaching Interests:

My teaching experience includes being a teaching fellow twice for the undergraduate fluid mechanics course at Purdue University, a structured study group leader for the undergraduate general chemistry course at the University of Michigan and a tutor for the undergraduate material and energy balances course, also at Michigan. During my studies at Michigan, I developed educational materials with Professor H. Scott Fogler for his books “Elements of Chemical Reaction Engineering, 5th Edition”, and “Strategies for Creative Problem Solving”. I also took a course on educational methods in engineering with Professors Phillip Wankat and Matthew Ohland at Purdue and attended a workshop hosted by Professors Richard Felder and Rebecca Brent. I am competent to teach any core chemical engineering course. In terms of course development, I would like to develop a 1-credit “Design and Construction of Tubing and Piping Systems” course targeted for senior undergraduates and first-year graduate students if facilities and funds are available. To tie my research into teaching, I am enthusiastically willing to teach or develop a course in materials characterization and reaction kinetics in catalysis targeted for first and second-year graduate students. I believe that a display of enthusiasm and joy of learning will engage and motivate students throughout courses. Giving students more responsibility will increase my teaching efficiency without coping out while ensuring that the students are challenged, simultaneously allowing me to retain time required to maintain my research group and scientific output.

Diversity Viewpoint:

Diversity supports resilience and facilitates work where several perspectives combine to create something strong and robust. Though diversity about gender and race dominate headlines, other forms of diversity such as skillset, nationality, generation, and much more are also important. In an increasingly globalized world, the need to be proactive in fixing the leaky pipeline for all those who wish to explore the world through science is ever so strong. During my PhD, I mentored two students from the Universidad Nacional de Colombia (one of whom is earning her PhD in Paris) in addition to four high school teachers (three from Indiana and one from a Native American reservation in New Mexico). From these experiences, I observed first hand that different viewpoints from a diverse group of scientists not only challenge outdated assumptions, but also ask questions that would otherwise been overlooked. I have hope, but the one thing we need more than hope is action. Portions of the pipeline are improving, but certain portions are still abysmal. Policies are a good start, but what really changes things are consistent actions.