CBE Seminar: “Active Center Design on Bulk and Highly Porous Surfaces for Atom-efficient Catalysis” (Rachel Yang, University of Michigan) [FACULTY CANDIDATE]
February 25 at 3:30 PM - 4:30 PM
Abstract:
Catalytic materials, with active centers tailored to specific chemical processes, have advanced significantly through innovations in synthesis, characterization, and computation, enabling increasingly complex and diverse compositions. However, a critical gap remains in understanding how the intrinsic properties of active centers govern key performance metrics including reactivity, selectivity, and stability. This gap arises from material complexity and the absence of effective kinetic descriptors, limiting the rational design of future catalysts. This talk explores how isolated metal sites in well-defined coordination environments can be systematically controlled, how these sites dynamically evolve under reaction conditions, and how governing material properties can be engineered to enhance catalytic performance. Utilizing crystalline, porous metal-organic frameworks (MOFs) and (non-porous) perovskite oxides as model systems with isolated metal sites in precise atomistic arrangements, we leverage their tunable physicochemical properties to establish robust structure-function relationships. Through probe reactions such as hydrocarbon oxidations, we elucidate how metal identity, coordination environment, valency, electronic structure, and ligand effects influence reaction rates and product selectivity, while also examining site evolution and deactivation pathways to identify mitigation strategies to improve stability and atom efficiency. In perovskite oxides, strategic substitutional doping yields promising photoactive materials that showcase unique ability to utilize low energy photons for photolysis of thermodynamically stable adsorbate-metal complexes that are not readily attainable for conventional supported architectures. Collectively, these vignettes demonstrate how chemical engineering fundamentals can be leveraged to uncover the mechanisms and limitations of promising solid catalysts, guiding the rational design of more sustainable catalytic systems.
Rachel Yang
Postdoctoral Research Fellow
Rachel A. Yang is currently a postdoctoral research fellow in Professor Eranda Nikolla’s group in the Department of Chemical Engineering at the University of Michigan Ann Arbor. In 2024, she earned her Ph.D. from the Department of Chemical and Biological Engineering at Princeton University under the guidance of Professor Michele L. Sarazen. Her dissertation work focused on metal-organic frameworks (MOFs) as modular heterogeneous transition metal CO2 adsorbents and catalysts for selective oxidative chemistries that are ubiquitous in industrial chemical synthesis applications. Her research investigated green syntheses of earth-abundant transition metal MOFs and coupled spectroscopic methods with kinetic experiments to probe the evolution of key material properties and the implications for reactivity/capacity, selectivity, and material stability throughout catalyst/adsorbent life cycles. Her current postdoctoral studies explore tailored synthetic techniques for doped perovskite oxide architectures with tunable properties (interfacial oxygen vacancies, metal oxidation states, etc.) for diverse reaction systems, including hydrocarbon and oxygenate oxidation/reduction, plastics upgrading, and light-driven surface transformations.