Position Title
University of California, Los Angeles
Prof. Anastassia Alexandrova
Abstract
Ensembles of metastable states of supported size-selected cluster catalysts determine activity, selectivity, and degradation resistance
Supported size-selected cluster catalysts are highly fluxional, and easily isomerize and/or change composition in reaction conditions, under the influence of temperature, electrochemical potential, binding and changing reagents, and reaction intermediates, as well as the kinetic energy exchange with hot reagents arriving at their surfaces. As a result, a dynamic ensemble of many catalysts states forms in reaction conditions, giving rise to many reaction pathways, and various channels enabling reactivity, selectivity, or catalyst degradation. Higher-energy metastable states can be most catalytically active. It will be shown how size-dependence of activity is a property of an ensemble of states, on the example of dehydrogenation on Pt cluster. Resistance to degradation (coking and sintering) as a function of cluster size and alloying is linked to thermal ensembles as well.
Biography
Anastassia Alexandrova is a Professor and Vice Chair in the Department of Chemistry and Biochemistry, UCLA. She obtained a B.S./M.S. Diploma with highest honors, from Saratov University, Russia, her Ph.D. in theoretical physical chemistry from Utah State University, and was then a Postdoctoral Associate and an American Cancer Society Postdoctoral Fellow at Yale University. Anastassia joined the faculty of UCLA and CNSI in 2010. The focus of her laboratory is computational and theoretical design and multi-scale description of functional materials: catalytic interfaces, ultra-hard alloys, quantum materials, artificial metalloenzymes, and molecular qubits and their assemblies for quantum computing. She is a recipient of numerous awards, such as NSF CAREER Award, Sloan Fellowship 2013, DARPA Young Faculty Award 2011, Fulbright Fellowship 2016, and ACS WCC Rising Star Award 2016, 2020 ACS Phys Early Career Award in Theoretical Chemistry, as well as UCLA’s Hanson-Dow award for excellence in teaching 2016, Herbert Newby McCoy award for excellence in faculty research 2016, undergraduate research mentorship award 2018, and distinguished teaching award (the highest honor for teaching given in UCLA) in 2019.