Title: Characterization of Dynamic Catalyst Structures and Impacts on Reactivity
Transition metal heterogeneous catalysts are vital for the industrial production of fuels, chemicals, and commodities that form the backbone of the modern energy and material industries. By facilitating chemical reactions with accelerated rates and promoting high selectivity to desired products, catalysts ensure efficient utilization of raw materials with minimal energy inputs. Understanding how the structure of metal species affects catalytic properties is an essential element of catalyst research that builds both fundamental intuition and informs the practical design of next-generation catalyst materials. Accurate characterization of the active catalyst species under reaction conditions is crucial in the development of these structure-function relationships.
In this talk, I will describe how a combination of tools including spectroscopic and microscopic characterization techniques, theoretical electronic structure calculations, and kinetic analysis through reactivity measurements can provide an atomic scale understanding of catalyst structures that contribute to reactivity. Employing this suite of tools, I will discuss the structural evolution of three catalyst systems that takes place at a variety of length scales: 1) surface segregation in AgPt alloy catalysts and impacts on CO oxidation activity, 2) sintering of Cu nanoparticles during methanol synthesis and increased stability with dilute Pt alloying, and 3) the phase change and fragmentation of Fe particles during the conversion of CO into solid carbon and CO2 via the Boudouard reaction. From the structure-function relationships derived here come important design principles, enabling us to promote positive attributes and mitigate deleterious phenomena with the ultimate goal of designing increasingly active, selective, and stable catalyst materials.