Ph.D. Final Defense - Andreas Towarnicky

Title: Understanding Proton-Coupled Electron Transfer on Polyoxometalates Abstract: Catalysis is essential to efficient chemical reactions, and improving its performance is key to meeting the challenges of global demand and sustainability while supporting our quality of life. Copious efforts pursue enhanced and innovative catalytic capabilities; however, their development still faces myriad complexities with incomplete understanding, slowing progress. Investigation via molecular models promises to unlock deeper understanding of the underlying physics, particularly when theoretical modelling is aligned with experiments and developed to general principles. The mechanics of proton and electron transfers are essential to many commercially relevant systems and offer fundamental descriptors for chemical behavior, especially the dynamics that arise with Proton-Coupled Electron Transfer (PCET). Metal oxides are an indispensable class of catalytic materials with potent and versatile abilities to influence PCET and other chemical activities. Many phenomena in these systems are rooted in their thermodynamics. Unifying them is the foundational descriptor of Bond Dissociation Free Energy, i.e. the BDFE(O–H), of hydroxide bonds on metal oxides. PolyOxoMetalates (POMs) are connected polyhedra of individual metal-oxide building blocks, and their atomic specificity is transformative for computational investigation and experimental characterization. Synthetic methods can obtain specific POMs, POM molecular solubilities lend them well to electrochemical investigation, and their precise structure and molecular scale facilitate advanced theoretical investigation at reasonable computational cost. Our present investigations leverage the molecular precision of POMs, the fundamental nature of PCET behavior, defined description via BDFE(O–H), experimental corroboration, and the insightful power of computational methods to deepen our understanding of structural influence