Shell Seminar Series

Bio

Dr. Sarah Perry is an Associate Professor of Chemical Engineering at the University of Massachusetts Amherst. She received BS degrees in Chemical Engineering and Chemistry, as well as an MS degree from the University of Arizona, and a PhD in Chemical and Biomolecular Engineering from the University of Illinois at Urbana-Champaign. Sarah was also a postdoctoral fellow at the University of California Berkeley and the University of Chicago. Her research interests are highly interdisciplinary, and utilize self-assembly, molecular engineering, and microfluidic technologies to understand the fundamental principles behind materials design to inform solutions to real-world challenges. She has been recognized with a number of teaching awards, along with the 3M Non-Tenured Faculty Award, the NSF CAREER Award, and 2024 ACS MacroLetters/Biomacromolecules/Macromolecules Young Investigator Award.

Abstract

Polyelectrolyte Complex Materials

Electrostatic interactions and polyelectrolyte complexation can be used in the self-assembly of a wide range of responsive, bioinspired soft materials ranging from dehydrated thin films, fibers, and bulk solids to dense, polymer-rich liquid complex coacervates, as well as more complex hierarchical structures such as micelles and hydrogels. This responsiveness can include swelling and dissolution or solidification, which can be harnessed to facilitate encapsulation and the subsequent fabrication of functional materials. In particular, we draw inspiration from nature, including membraneless organelles in cells which utilize liquid-liquid phase separation to create transient compartments, and the protein-based adhesives used by marine organisms. These materials are all formed due to weak, multivalent interactions involving intrinsically disordered proteins which can be thought of as analogous to unstructured polymers. We study how polymer chemistry, as well as the patterning of charge and other chemical functionalities can modulate both the potential for liquid-liquid phase separation via complex coacervation and the ability of these same materials to transform into solid polyelectrolyte complexes for use in a range of applications.

Bio

Dr. Nicholas (Nick) Thornburg is a Senior Reaction Engineer in the Energy Conversion and Storage Systems (ECaSS) Center. Nick joined ECaSS last summer after four and a half years in the Center for Integrated Mobility Sciences, and before then he began his NREL career in the Bioenergy Science and Technology Directorate as a postdoctoral researcher. His current research interests lie in multiphase reaction engineering for renewable small-molecule chemical syntheses facilitated by multiple renewable energy reactor inputs (e.g., electrons, photons, heat, hydrogen) for deep decarbonization of the chemical industry and heavy transportation sectors. Nick leads research and development projects in the following areas: renewable ammonia (NH₃) synthesis, separation, and utilization; electrochemical CO_x conversion, scale-up, and energy systems integration for the synthesis of valuable commodity chemicals; onboard fuel and hydrogen carrier reforming; and catalyst deactivation in integrated chemical process environments. Nick also holds a highly unique certificate in Management for Scientists and Engineers from Northwestern University’s Kellogg School of Management. His valuable combination of business and technical expertise is frequently sought by the NREL Innovation & Entrepreneurship Center’s technology incubation programs (West Gate, Shell GCxN, Chevron Studio and the NREL Investor Advisory Board) to help internal and external leaders identify compelling climate technologies and their corresponding market adoption solutions. Before joining NREL, Nick gained industrial research and development experience at The Dow Chemical Company and 3M. Nick holds a Bachelor of Science in Chemical Engineering from Washington University St. Louis and a Doctorate in Chemical Engineering from Northwestern University. His doctoral research focused on heterogeneous transition metal oxide catalysts in sustainable chemical manufacturing applications. Finally, outside of NREL, he is an Adjunct Professor of Chemical Engineering at the Colorado School of Mines, where he teaches an original course entitled “Advanced Reactor Design” offered to seniors and graduate students each spring semester. Nick is passionate about industrial decarbonization, mindfulness, entrepreneurship and student development.

Abstract

Reaction engineering: a lost (and found) art in science, technology and education

The heart (or, perhaps more appropriately, the stomach) of any chemical manufacturing process is the reactor, where chemical and physical transformations occur under precisely controlled conditions. For traditional industrial processes, the design, optimization and operation of chemical reactors are extremely well developed, drawing upon the principles of chemistry, physics, calculus and economics. However, new-age process concepts proposing to use “exotic” reactors and/or sustainable inputs (e.g., renewable carbon resources, electrons, photons, plasma) face a dearth of well documented reaction engineering principles and design practices that eclipses their rapid adoption. This presentation features three vignettes of (the return of) reaction engineering in sustainable process science: the first in the valorization of lignin from biomass; the second in understanding multimodal catalyst deactivation in industrial-scale reactors within the Catofin process for propane dehydrogenation; and the third in discovering an energy-advantaged ammonia reactive separation technology for Haber-Bosch plants. Lastly, inspiration from these examples manifests in a final brief plug for my senior- and graduate-level course entitled Advanced Reactor Design, now offered in spring semesters at the Colorado School of Mines. Overall, this seminar seeks to educate student researchers on practical means of advancing laboratory reactor technologies towards commercial practice.

Bio

Dr. Ambar Kulkarni is an Associate Professor in the Department of Chemical Engineering at UC Davis. After receiving his B.S. from the Institute of Chemical Technology (formerly UDCT), Mumbai (India), he moved to the U.S. to complete his Ph.D. (Georgia Tech, with David Sholl) and postdoc (Stanford, with Jens Nørskov). Since 2018, his research group has focused on combining advances in multiscale molecular modeling and machine learning with multifaceted experimental collaborations to address the challenges in catalysis, separations, and chemical sensing. His research group has experience with a variety of functional materials (e.g., zeolites, metal-organic frameworks (MOFs), metals, oxides), simulation methodologies, and automated analyses of experimental results (e.g., X-ray absorption spectroscopy, NMR spectroscopy, surface-enhanced Raman spectroscopy). Research in the Kulkarni group is supported through grants from the National Science Foundation (NSF), the Department of Energy (DOE),and several industry partnerships.

Kulkarni’s interdisciplinary research and teaching were recognized with the UC Davis College of Engineering Outstanding Junior Faculty Award for Excellence in Research and UC Davis College of Engineering Best Teaching Award in 2021. He received a 2021 NSF CAREER award for his work in designing MOFs for electrochemical applications. As the Inaugural UC Davis Graduate Mentor Fellow (2020 – present), Kulkarni has developed a series of mentorship workshops for UC Davis faculty aimed at improving the graduate student mentorship experience. When he is not staring at molecules on the computer screen, Ambar and his wife enjoy traveling to different countries, snowboarding, and photography.

Since 2020, Dr. Xun Tang joined the Cain Department of Chemical Engineering at Louisiana State University as a tenure track Assistant Professor. The current focus of research in his lab is on machine learning, optimal control, molecular self-assembly, and synthetic biology.

Abstract

How to Overcome the “Valley of Death” in Developing New Functional Materials?

The democratization of machine learning (ML) and access to growing supercomputing resources are revolutionizing the fields of materials science and heterogeneous catalysis. These advances have enabled high-throughput screening of catalyst libraries at unprecedented scales. However, compared to numerous reports of in-silico discoveries of novel catalysts for various reactions, the anticipated acceleration in lab-scale synthesis and testing, pilot-scale validation, and downstream development of novel processes has been relatively lackluster. In light of the growing severity of the climate change crisis and the changing national security landscape, there is an urgent need to bridge the gap between the computational discovery, experimental realization, and scale-up of promising catalysts.

Specifically, while state-of-the-art theoretical approaches can help identify promising active sites for a given chemical conversion, current methods are largely incapable of predicting the experimental protocol required to synthesize the target material in the lab. These knowledge gaps have contributed to slow and expensive innovation cycles that span multiple years or decades; many promising technologies do not survive the so-called “valley of death.”

This talk illustrates how an interdisciplinary and team-oriented approach can be used to address key challenges within the heterogeneous catalysis community. Using examples spanning catalysis science, materials design and precision health care, this talk will highlight (1) the capabilities and limitations of the current computational methods, (2) the unique insights provided by theory (used in close collaboration with experiments),  and (3) the central role of software development, data engineering, and robotics as enablers for ML-based materials development pipelines. Taken together, this talk will present a cohesive vision for the expanding role of theory and data science (when used judiciously with experimentation) to accelerate innovations in emerging technologies.  

One of our most important scientific challenges is to design catalysts that produce H₂ from “minimum CO₂” sources. One strategy is by aqueous phase reforming (APR) of sugar alcohol molecules derived from biomass. However, H₂ yields have been disappointing, indicating that catalysts and reaction conditions require optimization. This requires a detailed understanding of the mechanism. There are three primary steps: dehydrogenation, decarbonylation, and water gas shift. However, details of the dehydrogenation step remain unknown due to the large and complex structures of the reactant molecules, the aqueous reaction conditions, and the participation of multiple active sites in the mechanism. To address these things, we study the effect of liquid H₂O solvent and multiple active sites on the mechanism of the APR of CH₃OH. Specifically, we compare microkinetic modeling results with observations from ATR-IR to provide insight into the dehydrogenation of CH₃OH on Pt/Al₂O₃. Microkinetic modeling utilizes interfacial free energies calculated with our method of multiscale sampling, which combines DFT with classical MD to address explicit influences of solvent molecules on interfacial species enthalpies and entropies. Further, we investigate sites on the terraces of large Pt particles as well as at the Pt/Al₂O₃ perimeter. We show that while Pt terraces follow an “alcohol route”, the Pt/Al₂O₃ perimeter follows an “aldehyde route”. Despite a small promotional effect in aiding to break the CO-H bond, liquid H₂O ultimately inhibits the rate in both sites. On terrace sites, this is due to stabilization of COH, which impedes dehydrogenation. On perimeter sites, H₂O binds strongly to Al₂O₃, inhibiting CH₃OH diffusion to the Pt/Al₂O₃ perimeter. Further, it donates protons to CH_xO species, effectively pushing the reaction in reverse. Understanding of these details enables envisioning ways to tune catalyst composition and solvent effects to better promote the rate of sugar alcohol dehydrogenation on supported metal catalysts.

Bio

Dr. Rachel B. Getman is a Professor and the Bernice L. Claugus Endowed Chair of Chemical and Biomolecular Engineering at The Ohio State University. Prior to joining Ohio State, she was faculty at Clemson University, where she was the first woman to be tenured, and, subsequently, promoted to full professor in her department in its 100+ year history. Dr. Getman’s research group uses quantum chemical calculations and Monte Carlo and molecular dynamics simulations to learn about molecular phenomena at fluid/solid interfaces. Dr. Getman is particularly interested in how solvent configurations and solvation energetics influence processes in heterogeneous catalysis and separations. Dr. Getman has received a CAREER award from the National Science Foundation and a Professor of Affordable Learning Award from the South Carolina Affordable Learning Group. She presently serves the American Institute of Chemical Engineers (AIChE) Catalysis and Reaction Engineering Division as the 1^st Vice Chair and Vice Area Chair. Dr. Getman earned dual BS degrees in Chemical Engineering and Business Administration from Michigan Technological University in 2004. She earned her PhD from the University of Notre Dame in 2009, where she worked with William Schneider simulating catalytic oxidations under ambient conditions. From 2009 – 2011, she was a Postdoctoral Research Fellow with Randall Snurr at Northwestern University, simulating gas storage in metal-organic frameworks (MOFs). Dr. Getman started her independent career in August 2011.

Abstract

Influence of Liquid Water on the Thermodynamics, Kinetics, Mechanism, and Rate of Hydrogen Production from Methanol over Pt/Al2O3 Catalysts

Designing catalyst surfaces to promote desired and suppress undesired chemistry is a key challenge in interfacial engineering, which relies on harnessing control over the free energies of interfacial species. This can be done by tuning the composition of the solid catalyst and/or the solvent; for example, by choosing solvents that exhibit optimal interactions with the interface and/or interfacial species. But this view, which is essentially taken through the lens of enthalpy, is limiting. Whereas enthalpy is defined by intermolecular interactions (e.g., hydrogen bonding, van der Waals interactions), entropy has a much richer set of design knobs. Considering solvation of species on a solid surface, we find that entropy is strongly influenced by interface hydrophilicity, confinement, and external electric fields in ways that supersede the changes in enthalpy due to the associated intermolecular interactions. Specifically, we have calculated the free energies of solvation of oxygenate (C_xH_yO_z) species adsorbed to Pt, Pt/Al₂O₃, FAU zeolite, and FAU zeolite with OH defects, which represent hydrophobic and hydrophilic, unconfined and confined systems, under pure water and mixed water/methanol solvents using multiscale modeling that combines density functional theory and force-field molecular dynamics. We find that the entropic contributions to the free energies of solvation, as well as the phenomena that define them, depend on the interface and that properties such as the isothermal compressibility of the interfacial solvent, the extent to which solvent molecules form hydrogen bonds with each other versus interfacial species, and the polarity of the interfacial species impact entropy but not enthalpy. We further find that the ratio of entropy to enthalpy varies depending on the system, spanning from 70%-140% in these systems. These findings suggest that it is possible to tune interfacial properties such that entropy is the dominant contribution to free energy, and further, that entropy is more tunable than enthalpy. There are henceforth unprecedented opportunities for interfacial systems to fine-tune free energies by designing processes based on their entropies. As a step in this direction, we extend our analysis to peptides for ion separations, a process that has been hypothesized to be dominated by entropy.

Bio

Dr. Emily Pentzer is Professor in the department of chemistry and the department of materials science and engineering at Texas A&M University. She received a BS in chemistry from Butler University (2005) and PhD in chemistry from Northwestern University (2010), where her thesis focused on preparing and polymerizing unsaturated lactones and lactams. She then worked with Professor Todd Emrick in the Polymer Science and Engineering Department at UMass Amherst where she focused on the synthesis and assembly of electronically active materials for organic photovoltaics. In 2013, Dr. Pentzer started her independent career as an assistant professor of chemistry at Case Western Reserve University and she moved to Texas A&M in 2019.

The Pentzer Lab’s research centers on developing new polymeric materials and assemblies as a route to understand structure-property-application relationships and access functions not possible with current state-of-the-art systems. Her group works on the encapsulation of “active” liquids and gases, designing and synthesizing new polymer chemistries, and developing feedstocks for additive manufacturing to produce multifunctional materials, and these materials have applications in thermal energy management, electrochemical energy storage, and carbon capture.

Dr. Pentzer regularly participates in events aimed at professional development of students and post-docs and facilitating their transition to vibrant STEM careers. She has received several awards including the NSF CAREER award (2016), PMSE Young Investigator Award (2017), CWRU Faculty Diversity Excellence Award (2019), ACS WCC Rising Star Award (2021), and was named a Texas A&M Presidential Impact Fellow (2021) and finalist for the Blavatnik Award in physical sciences and engineering (2022). She served as an Associate Editor for Polymer Chemistry from 2015-2023 and served as Alternate Councilor for the Polymer Division (POLY) of the American Chemical Society from 2020-2022. She currently serves as the inaugural Editor in Chief of RSC Applied Polymers (2023-present) and member of the third cohort of the New Voices program of the National Academies of Science, Engineering, and Medicine (2024-2026).

Abstract

Stabilization of Non-Aqueous Pickering Emulsions and their use for Encapsulation of Water-Sensitive Liquids

Emulsions stabilized by solid particles (e.g., Pickering emulsions) are attractive platforms for creating composite structures, including capsules with liquid core. This presentation will address the use of non-aqueous Pickering emulsions for the encapsulation of compositionally sensitive liquids, including salt hydrate phase change materials (PCMs) and ionic liquids (ILs).  Hydrophobized graphene oxide nanosheets are dispersible in an oil which becomes the continuous phase, and upon agitation of this dispersion with an immiscible liquid, emulsions are formed in which the modified particles reside at the fluid-fluid interface, imparting stabilization. This presentation will address the use of these emulsions for encapsulation of PCM or IL by polymer formation at the interface, providing a core-shell structure, as well as the application of these composite capsules in thermal energy management (e.g., PCM core) and carbon capture (e.g., IL core).

Bio 

Dr. Michael J. Gordon is the Warren G. and Katharine S. Schlinger Professor of Chemical Engineering and Chair of the Department of Chemical Engineering at UCSB. He received his BS/MS in Chemical Engineering from the Colorado School of Mines, MS (Applied Physics) and PhD (Chemical Engineering) from the California Institute of Technology, and spent two years as a post-doc in Grenoble, France at the CNRS Laboratoire des Technologies de la Microélectronique.

Mike joined UCSB in 2007, was the dept’s Vice-Chair for Undergraduate Affairs from 2019-2023, and became Department Chair in 2023. He is heavily involved in UCSB’s Institute for Collaborative Biotechnologies and the Solid-State Lighting and Energy Electronics Center, as well as the Center for Programmable Energy Catalysis with the Univ. of Minnesota. Mike is a Packard Fellow, he received the NSF CAREER award, and he was the Robert E. Vaughn Lecturer at Caltech. He was also recently elected as a Fellow of the American Vacuum Society and he has received multiple department and campus-wide teaching awards.

Professor Gordon’s research focuses on the synthesis, characterization, engineering, and simulation of nanostructured materials and systems for photonic, energy, chemical conversion, and biological applications.

Abstract

Bio-inspired and biologically-enabled photonic materials

Near- and sub-wavelength photonic structures are used by different organisms (e.g., insects, cephalopods, fish, birds) to create vivid and often dynamically-tunable colors, as well as create, manipulate, or capture light for vision, communication, crypsis, photosynthesis, and defense. This talk will highlight our work to understand and translate these biological mechanisms of light manipulation and surface ‘engineering’ into new materials and device venues, with the ultimate goal of using biological components and paradigms to create novel multi-scale structures with functional properties. Examples to be discussed include: (1) insect eye features for anti-reflection, light extraction engineering, and anti-fouling; (2) marine diatom-inspired metasurfaces for sensing and high contrast reflectors; and (3) electrochemical systems that integrate and control proteins (e.g., reflectin, the intrinsically disordered protein whose assembly is responsible for dynamic color in squid) and biomimetic light-interacting molecules at biotic-abiotic interfaces to achieve tunable optical properties.

Bio

Dr. Kejun Chen is a Development Engineer at First Solar, where she engages in advanced research on high-efficiency tandem solar cells. She graduated from the Department of Chemical & Biological Engineering at Mines in 2023, under the
co-supervision of Prof. Sumit Agarwal and Dr. Pauls Stradins from the National Renewable Energy Laboratory (NREL). Her PhD research focused on pioneering pathways to
high-performance crystalline silicon-based passivating contact solar cells. Outside of her professional endeavors, Dr. Chen is passionate about outdoor activities and maintaining a healthy lifestyle. She enjoys cooking wholesome, nutritious foods and is dedicated to practicing well-being and Mindfulness through meditation and yoga. 

Abstract

Pathways to High Performance Silicon-Based Photovoltaic Technology

Solar photovoltaic (PV) technology, led by crystalline silicon (c-Si) solar cells, is a key renewable energy solution. To reduce the levelized cost of energy (LCOE) and boost adoption, improving their efficiency beyond the current 24% is crucial. This talk will discuss the advancement of poly-Si/SiOx passivating contacts, achieving efficiencies of 25-26%, through methods such as selective etching to enhance light absorption,
X-ray diffraction for layer thickness measurement, gallium doping for better passivation, and Electron Paramagnetic Resonance spectroscopy for defect analysis. These efforts aim to improve the efficiency and cost-effectiveness of c-Si solar cells for industrial use. The talk will also highlight current leading research in solar industry, including perovskite-based tandem technology and the significance of long-term reliability in solar PV.

Bio

Abstract

High-Entropy Catalysts for Sustainable Chemical and Energy Conversions

Development of advanced catalysts for chemical transformation and energy conversion is usually challenged by the dilemma between activity and stability enhancements. This usually originates from the fact that many catalytically active sites are typically metastable surfaces, phases, or atomic structures. Here we discuss the use of high-entropy alloys to bypass this limitation. We aim to elucidate the unique structure-property relationships of high-entropy catalysts under harsh reaction conditions, including chemical transformations related to NH₃ and oxygen reduction in fuel cells. Our work highlights the great potential of high-entropy materials for catalyzing chemical transformation and energy conversion reactions.

Luis Solorio, PhD is the director of the Tissue Microenvironment & Therapeutics Lab (TMET) at Purdue University, which focuses on applying principles of tissue engineering, medical imaging, and drug delivery for the development of modular 3D tissue-engineered constructs that can be used to evaluate the cancer cell response to microenvironmental cues. He joined the faculty at Purdue University in 2016 as an Assistant Professor in the Weldon School of Biomedical Engineering. He is a U.S. Army veteran who proudly served for 5 years immediately after graduating high school. Dr. Solorio has been trained in both engineering and chemistry, obtaining a B.S. in Biomedical Engineering and Chemistry from Saint Louis University in St. Louis in 2006.  Dr. Solorio received his M.S. degree in Biomedical Engineering from Rensselaer Polytechnic Institute in 2007 working with Dr. Jan Stegemann exploring methods of growth factor delivery to drive differentiation of mesenchymal stem cells. Dr. Solorio then received his Ph.D. in Biomedical Engineering from Case Western Reserve University in 2012 with Dr. Agata Exner focusing on the use of medical imaging to guide the design and development of controlled release platforms. He is the recipient of the K99 Pathway to Independence Award, the Mark Foundation Aspire Award, and the MetaVivor Early Career Award.

Bio

Abstract

Mechanical Drivers of Tumor Dormancy

Metastasis is the single greatest driver of cancer-related mortalities regardless of the tumor’s tissue of origin. A defining hallmark of metastasis is the ability of tumor cells to modulate the microenvironment to facilitate invasion and colonization. These microenvironmental changes within pre-metastatic tissues play a key role in determining the invading cell’s fate. In this talk, I will describe my lab’s efforts toward understanding how the matrix composition and mechanical forces present within the metastatic microenvironment govern cell colonization and metastatic outgrowth. More specifically, we use a combination of tissue engineering approaches and mouse models to interrogate how changes in the mechanical microenvironment influence the cell growth cycle and dormancy, creating potential novel therapeutic avenues. Additionally, I will discuss the development of a tumbling microrobot system that can be used for localized drug delivery applications, biopsies, and micromanipulation.