报告题目 | Dynamic catalytic interfaces: ensembles of metastable states break the rules of catalysis |
报告人 | Anastassia Alexandrova |
报告人单位 | Department of Chemistry and Biochemistry, and the Department of Materials Science and Engineering, UCLA |
报告时间 | 2024年3月26日（星期二）16：00—18:00 |
报告地点 | 物质科研楼3楼学术报告厅 |
主办单位 | 精准智能化学重点实验室 |
报告摘要 | I will show how reletlessly dynamic some catalytic interfaces can be in conditions of catalysis, and what implications this has for our understanding of catalytic mechanisms, and the relationship between theory and experiment in this field. Fluxional catalysts, a prime example of which is supported nano clusters, populate many distinct structural and stoichiometric states, forming a constantly changing statistical ensemble, which can be off-equilibrium. Multitude of metastable states in this ensemble dictate the catalytic activity, selectivity, durability, and spectral characteristics. Many assumptions and rules in catalysis need a revision within this new paradigm. Firstly, catalyst dynamics is an essential part of the catalytic process. Scaling relations routinely break down. The most active catalyst state may not be the most stable (i.e. most dominant). On the other hand, operando spectra are overwhelmed by the signal form the most dominant species. High temperature phase diagrams contain many structures per phase, and get enthalpically destabilized but entropically stabilized by fluxionality, each phase to its own degree. The Ostwald theory of sintering needs a revision. These concepts will be presented using several catalytic systems studied collaboratively with experiment. Showcase systems will include dehydrogenation on supported Pt catalysts, ORR and HER on supported Pt catalysts, and CO2RR on bulk Cu electrodes. I will also present a new challenge for theory: kinetically-controlled operando reconstruction of Cu electrodes in reduction conditions. Some of our results will hopefully prompt experimental developments. For example, detecting dynamic minority active species of the catalytic interface remains a challenge. |
报告人简介 | Anastassia Alexandrova is a Professor in the Department of Chemistry and Biochemistry, and the Department of Materials Science and Engineering, 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 theory and computation for design and multi-scale modeling of functional materials: dynamic catalytic interfaces, artificial metalloenzymes, molecular qubits and their assemblies, and quantum materials. Anastassia serves as a Senior Editor of the Journal of physical Chemistry (ACS). 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, 2021 Max Planck-Humboldt medal, 2023 Gold Shield Faculty Prize, 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 2019 distinguished teaching award (the highest honor for teaching given in UCLA). |
