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.  

Bio

Dr. Tianquan (Tim) Lian received BS degree from Xiamen University in China in 1985, MS degree from Fujian Institute of Research on the Structure of Matter (under the supervision of Prof. Hongyuan Shen) in 1988 and PhD degree from University of Pennsylvania (under the supervision of late Prof. Robin Hochstrasser) in 1993. After postdoctoral training with the late Professor Prof. Charles B. Harris in the University of California at Berkeley, Tim Lian joined the faculty of chemistry department at Emory University in 1996, where he was promoted to Associate Professor in 2002, Full Professor in 2005, Winship Distinguished Research Professor in 2007, and William Henry Emerson Professor of Chemistry in 2008. Tim Lian is currently the Editor-in-Chief of the Journal of Chemical Physics (since Jan. 1, 2019). Tim Lian is the recipient of a few notable recognitions, including NSF CAREER award, Alfred P. Sloan fellowship, Kavli Frontier of Science fellow (since 2012), APS fellow (since 2015), ACS PChem Division Award for Senior Experimental Physical Chemistry (2022), and AAAS Fellow. Tim Lian’s research interest is focused on in situ probe of the interfacial structure, dynamics, and reaction mechanisms in nanomaterials and electrochemical and photoelectrochemical devices. 

Abstract

In Situ Probe of Structure and Dynamics at Metal electrode/Electrolyte Interface: Interfacial Field, Electro-induction Effect, and Hot Electron Transfer

Structure and dynamics of electric double layer (EDL), the sub-nanometer region at the electrode/electrolyte interface, are essential to the function and performance of many energy conversion and storage devices, ranging from electrolyzers, photoelectrochemical cells, fuel cells to batteries. In situ probe of the EDL structure and dynamics at the molecular level requires advanced molecular spectroscopic tools with interfacial sensitivity and/or selectivity. In this talk, I will discuss three recent studies in developing and applying vibrational sum frequency generation (VSFG) spectroscopy and surface enhanced Raman spectroscopy (SERS) as powerful in situ interface specific/sensitive vibrational spectroscopic tools. 1) Using combined VSFG and DFT calculation, we determine the binding structure of a molecular CO₂ reduction catalyst on metal electrodes and interfacial electric field profile in the EDL, revealing surprisingly large electrode induction effects on molecular catalyst. 2) Using combined SERS and MD simulation, we obtain an atomistic view of the structure of solvent and ion molecules at the EDL, revealing an unconventional interfacial water structure change at high negative electrode polarizations in water-in-salt electrolytes. 3) Using time-resolved VSFG, we directly measure hot electron transfer induced vibrational dynamics of adsorbates on metal electrodes, suggesting the possibility of plasmon (or light)-enhanced electrochemistry.

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

Solvation Thermodynamics at Liquid-Solid Interfaces: The Remarkable Contributions and Origins of Entropy

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.