Seminar Speaker: Katherine Sytwu, Lawrence Berkeley National Laboratory

“Lights, Camera, Action! Understanding and Controlling Nanoparticle Transformation Dynamics”

Abstract

Nanoparticle transformations underlie the successes and failures of numerous chemical conversion processes including catalysis, but these atomic- and nanoscale dynamics are difficult to detect, control, and ultimately understand. In this talk, I will demonstrate how advances in situ transmission electron microscopy (TEM), tailored nanoscale light-matter interactions, and customized machine learning enable a detailed understanding of nanoparticle transformations under reaction conditions. Using the palladium hydride (PdHx) phase transition as a model system, we identify how nanoparticle structure dictates transformation dynamics. By coupling these catalysts to a light-harvesting plasmonic antenna, these structure-dependent dynamics can be spatially modified to energetically-unfavorable configurations, suggesting how light can “unlock” new active sites on nanoparticle catalysts. To scale up these observations for ensemble-level statistics, we adapt machine learning methods to analyze in situ TEM data streams reliably. Our work highlights how state-of-the-art characterization opens new opportunities to explore, understand, and control non-equilibrium behavior at the nanoscale.

Speaker Biography

Katherine Sytwu is currently an Intelligence Community Postdoctoral Fellow at the Molecular Foundry at Lawrence Berkeley National Laboratory, working with Professor Mary Scott to develop explainable and customized machine learning tools for in situ TEM analysis. She received her B.S. in physics and B.A. in mathematics from Rutgers University and her M.S. and Ph.D. in applied physics from Stanford University. For her dissertation, she worked with Professor Jennifer Dionne to explore how plasmonics enables new dynamics at the nanoscale.