(6cb) Engineering the Catalytic Environment: Synthetic, Mechanistic, and Spectroscopic Approaches for Developing Design Principles

A grand challenge that society faces is satisfying the demand for energy and chemicals using efficient and sustainable carbon resources. Catalysis is inevitable in the solution of this problem; however, viability hinges on the intimate relationship between activity and selectivity. My research will focus on understanding the reaction mechanism for desired and undesired pathways and identifying and manipulating the catalytic active site and reaction environment. My group will combine the controlled synthesis of porous materials (e.g., zeolites and zeotypes), modern in situ and in operando spectroscopic techniques (e.g., Raman, IR, XAS, neutron), and intrinsic kinetic measurements to understand how complex interactions at the catalytic interface can affect the rates and selectivities for a given reaction pathway. To minimize our carbon footprint and contribute to lasting and sustainable solutions, my group will specialize in the conversion of greenhouse gases and the upgrading of emerging (e.g., shale gas) and renewable (e.g., bio-derived) resources. Initial research areas will include: 1) understanding the effects of confinement on thermal and electrochemical CO2 reduction ; 2) the upgrading of bio-derived platform chemicals through thermal- and electrochemical pathways; 3) the development of catalytic systems for low temperature ammonia synthesis; and 4) the discovery of tandem catalytic systems for light alkane upgrading.

Research Experience:

Methods for Understanding Inner- and Outer-Sphere Interactions at the Liquid-Solid Interface: Quantitative Structure-Activity Relationships for Oxidation Reactions; Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign (advised by David W. Flaherty)

Catalytic reactions that proceed at the liquid-solid interface formed between solvent mixtures and the surface of a heterogeneous catalysts possesses all of the complexities of catalysis at the gas-solid interface but are further complicated by interactions with solvent molecules. My Ph.D. research has focused on the development of quantitative relationships that describe the complex interactions between solvent structures, confining surfaces, and reactive intermediates during alkene epoxidation. Through the combination of controlled zeolite synthesis, in situ spectroscopic techniques, and rigorous kinetic measurements, we made several significant contributions to the field of liquid-phase oxidations:

• The functional Lewis acid strength of early transition metal-substituted zeolites is intimately correlated with the electrophilicity of reactive species formed upon activation of hydrogen peroxide. The difference in Lewis acid strength leads to a 100,000-fold difference in rates of alkene epoxidation (and sulfide oxidation) and 100-fold difference in selectivity among groups 4 and 5-substituted zeolites.
• The presence of a confining void (i.e., within a zeolite) selectively stabilizes styrene epoxidation transition states and leads to a 20-fold increase in rates and selectivities. The pore does not, however, influence the electronic structure of the active site or reactive intermediate.
• Polar functional groups within a micropore can spontaneously nucleate small clusters of H₂O that interact with surface intermediates (e.g., transition states, adsorbates), which leads to a 100-fold change in the rates and selectivities of n-alkene epoxidation.

Collectively, our findings have shown experimental evidence for the free-energy relationships that describe these complex interactions and have shown that orthogonal modifications of the solvent, surface, and active site can all be used to control catalysis at the liquid-solid interface.

My postdoctoral research will be performed with an expert in electrochemistry and electrocatalysis. This is by design, so that my independent career research can couple modern thermal- and electro-catalytic methods to study and why reactions proceed in response to chemical- and electrical stimuli.

Selected Publications:

• Bregante, D.T.; Johnson, A.M.;Patel, A.Y.; Ayla, E.Z.; Cordon, M.J.; Bukowski, B.C.; Greeley, J.; Gounder, R.; Flaherty, D.W.; Journal of the American Chemical Society 2019, 141, 7302-7319.
• Bregante, D.T.; Thornburg, N.E.; Notestein, J.M.; Flaherty, D.W.; ACS Catalysis 2018, 8, 2995-3010.
• Bregante, D.T.; Patel, A.Y.; Johnson, A.M.; Flaherty, D.W.; Journal of Catalysis 2018, 364, 415-425.
• Bregante, D.T.; Flaherty, D.W.; Journal of the American Chemical Society 2017, 139, 6888-6898.
• Bregante, D.T.; Priyadarshini, P.; Flaherty, D.W.; Journal of Catalysis, 2017, 348, 75-89.
• Bregante, D.T.;^‡ Wilson, N.M.;^‡ Priyadarshini, P.; Flaherty, D.W.; Catalysis, 2017, 29, 122-212.

Selected Awards:

• University of Illinois Dissertation Completion Fellowship (2019 – 2020)
• National Defense, Science, and Engineering Graduate Fellowship (2016 – 2019)
• ACS Graduate Student Award in Environmental Chemistry (2018)
• School of Chemical Sciences Graduate Teaching Award (2018)
• Frederic and Edith Mavis Future Faculty Fellowship (2017 – 2018)
• AIChE Catalysis and Reaction Engineering Travel Award (2018)
• Richard J. Kokes Travel Award (2017)
• Samuel Parr Graduate Fellowship (2015 – 2016)

Teaching Interests:

Teaching, both in the classroom and as a mentor in the lab, is a major driving force for my desire to become a professor. As a chemical engineer by training, I am excited and qualified to teach core undergraduate coursework in chemical kinetics and reactor design, thermodynamics, fluid mechanics, heat and mass transfer, and separations, in addition to graduate-level applied mathematics, transport phenomena, and chemical kinetics. I also plan to leverage my research experience and personal interests to develop and teach a senior-undergraduate/graduate elective on the various facets of catalysis (i.e., heterogeneous, homogeneous, electro, and enzyme), which will complement a graduate-level chemical kinetics course.

My teaching experience extends beyond the classroom and into the laboratory, as students and postdoctoral researchers within my research group will utilize an interdisciplinary approach to problem solving that leverages techniques and thought processes from chemistry, materials science, and physics.

Teaching Experience:

• Kinetics and Reactor Design (Olivet Nazarene University; Spring 2019) – Ad hoc Instructor
• Chemical Kinetics and Catalysis (Illinois; Fall 2018) – Teaching Assistant and Guest Lecturer
• Mass Transfer and Operations (Illinois; Fall 2017) – Teaching Assistant and Guest Lecturer
• Chemical Structure and Reactivity (UC Berkeley; Summer 2014) – Teaching Assistant
• Organic Chemistry I (UC Berkeley; Fall 2013) – Teaching Assistant

Service:

I have served as an organizer, abstract reviewer, and session chair for the Catalysis Club of Chicago’s 2019 symposium and the 2019 AIChE National Conference (Section 20a). Aside from this service, I am passionate about developing and encouraging young scientists to pursue careers in STEM to solve some of the world’s most-important problems. A glaring problem within most STEM fields, is the large disparity in the representation of different groups (e.g., gender and racial), which suggests that, as a society, we are not developing or utilizing the population to its full potential. Addressing this issue requires that STEM be made tractable and fun at an early age so that these traditionally-underrepresented groups are encouraged to pursue it. Throughout my undergraduate and graduate career, I have participated in numerous student groups (Berkeley Engineers and Mentors; Girls Adventures in Mathematics, Engineering, and Science) whose goal is to promote science and engineering to young students. In my independent career, I will also serve as a faculty mentor to similar groups (or encourage my students to start one), so that we may increase the pool of young scientists. I also routinely serve on student panels for undergraduate students who are interested in pursuing graduate studies.

At Illinois, I have mentored 4 undergraduate students through a NSF-funded REU that aims to increase female participation in research. Additionally, I have served as a research mentor in the summer pre-doctoral institute here at Illinois, whose mission is to immerse incoming graduate students from underrepresented minorities in research with a senior graduate student to aid in navigating a Ph.D. program. As a professor, I will make it a priority to host or participate in similar programs to develop researchers from all walks of life. Overall, I hope to continue my engagement-with and development-of the scientific community.

For additional information, please see Breganteresearch.org