(4dx) Designing the Active Centers and Solvating Environments of Heterogeneous Catalysts for Energy, Organic Synthesis, and the Environment

Heterogeneous catalysis plays a pivotal role in modern society, from feeding the world (NH₃ synthesis), to enabling transportation (fluid catalytic cracking), to cleaning the air (automotive catalytic converters). This notable history and current technological significance reflects the important role that heterogeneous catalysis can play in solutions to grand challenges facing our society today, such as global climate change and sustainable production of fuels and chemicals that improve human health and quality of life. The milieu of the heterogeneous catalyst surface consisting of active centers and their solvating environments provides a rich design space to control and harness fundamental intermolecular and interfacial interactions to direct molecules through kinetically favorable and selective conversion pathways, over the course of many turnovers. My independent research group will synthesize heterogeneous catalysts with well-defined active centers and solvating environments, in order to elucidate the fundamental principles of structure-reactivity relationships, guided by quantitative kinetic measurements and in situ or operando characterizations of the catalysts. Such synthesis–structure–function relationships will contribute to the development of new catalytic technologies that address challenges in energy, organic synthesis, and the environment.

Graduate Research (Purdue University, Chemical Engineering; Advisor: Rajamani Gounder)

Dissertation Title: “Structure and Solvation of Confined Water and Alkanols in Zeolite Acid Catalysis”

My graduate studies centered on the relationship between function and structure of zeolite acid catalysts relevant to conversion of emergent feedstocks such as biomass. I described how the catalytic versatility of Lewis acid zeolites arises from structurally diverse active sites located at defective crystal grain boundaries,¹ and from their confinement within pore environments of different polarity that influence the stabilization of reactive intermediates.² I developed molecular descriptions of the kinetic effects of solvent structures within Brønsted acid zeolites, including the clustered nature of alkanols³ and hydrogen-bonded networks formed by water,⁴ which can be described by non-ideal thermodynamic formalisms that apply generally for many reactions solvated by condensed phases confined in micropores.⁵ This work was also enriched by fruitful collaborations with theoreticians (Prof. Jeffrey Greeley).

Postdoctoral Research (University of Wisconsin–Madison, Chemistry; Advisor: Shannon S. Stahl)

Project Title: “Chemoselective Heterogeneous Catalysts for Oxidative Amide Coupling”

As an NIH postdoctoral fellow, I studied the chemistry of aerobic oxidations catalyzed by heterogeneous catalysts consisting of earth-abundant metals incorporated into nitrogen-doped carbon (M–N–C). These materials, and their applications, reside at the interface between electrocatalysis, thermal catalysis, and organic synthesis. Using M–N–C as a model system, I discovered that the electrochemical half-reaction steps typically considered in aerobic oxidations can be supplanted by previously unrecognized thermochemical steps when certain organic molecules are employed. In a parallel project, I combined knowledge of the surface chemistry of N-doped carbons with molecular coordination chemistry to synthesize M–N–C materials with solely mononuclear active centers by developing new methods that are more selective and general than state-of-the-art synthetic routes. Through this training, I have developed technical expertise in liquid-phase aerobic oxidation catalysis, electrochemistry, and inorganic synthesis; and broadened my knowledge of electrocatalysis and organic synthesis. These skills acquired in the “molecular world” of chemistry will pair well with my chemical engineering expertise in quantitative kinetics, zeolite synthesis, and in situ spectroscopy, to bring fresh insights to challenges that increasingly require multidisciplinary solutions.

Teaching Interests

Teaching and mentorship are integral to the practice of science and have been formative in my scientific training and in my motivation to pursue a career in academia. My background in heterogeneous catalysis requires understanding several fundamental subject areas of chemical engineering (kinetics, thermodynamics, and transport), and I am prepared to teach these and any other chemical engineering course, though my preference is to teach chemical reaction engineering. I have experience facilitating discussion sections and guest-lecturing as a teaching assistant for chemical reaction engineering and material and energy balances courses, in addition to guest-lecturing in graduate-level heterogeneous catalysis elective courses at Purdue. I also deepened my knowledge of pedagogy and honed my teaching craft by earning the Graduate Teacher Certificate awarded by the Center for Instructional Excellence at Purdue. This experience included a graduate-level course in Educational Methods in Engineering taught by Prof. Philip C. Wankat, which improved my approaches to designing course objectives, fairly evaluating students, and fostering an inclusive classroom environment. I also received critical observation and feedback on my lecturing from Prof. Wankat and other chemical engineering faculty as part of this certification. At UW–Madison, I mentored three graduate students and was recognized with a mentoring award from the Chemistry Department. I am committed to furthering the principles of diversity, equity, and inclusion by mentoring graduate students from under-represented backgrounds; promoting a research group culture with clearly delineated expectations, equitable distribution of responsibilities, and democratic decision-making; and encouraging the admittance and recruitment of a diverse graduate student population.

Selected Publications (complete list at https://sites.google.com/site/jasonsbates/publications)

(1) Bates, J. S., Bukowski, B. C., Harris, J. W., Greeley, J., Gounder, R., “Distinct Catalytic Reactivity of Sn Substituted in Framework Locations and at Defect Grain Boundaries in Sn-Zeolites.” ACS Catalysis, 9 (2019) 6146–6168.

(2) Bates, J. S., Gounder, R., “Influence of Confining Environment Polarity on Ethanol Dehydration Catalysis by Lewis Acid Zeolites.” Journal of Catalysis, 365 (2018) 213–226.

(3) Bates, J. S., Gounder, R., “Clustering of Alkanols Confined in Chabazite Zeolites: Kinetic Implications for Dehydration of Methanol-Ethanol Mixtures.” Journal of Catalysis, 390 (2020) 178–183.

(4) Bates, J. S.^†, Bukowski, B. C.^†, Greeley, J., Gounder, R., “Structure and Solvation of Confined Water and Water-Ethanol Clusters within Microporous Brønsted Acids and their Effects on Ethanol Dehydration Catalysis.” Chemical Science, 11 (2020) 7102–7122. ^†Equal contributions.

(5) Bates, J. S., Gounder, R., “Kinetic Effects of Molecular Clustering and Solvation by Extended Networks in Zeolite Acid Catalysis.” Chemical Science, 12 (2021) 4699­–4708.