TODAY: Kelsey Stoerzinger, 02-Sep-25, 12:20pm Central
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Ellad Tadmor
Sep 2, 2025, 9:57:02 AM (5 days ago) Sep 2
to aem-solid...@umn.edu
AEM Mechanics Research Seminar
Tuesday 02-Sep-2025, 12:20pm Central
Prof. Kelsey A. Stoerzinger
Department of Chemical Engineering and Materials Science, University of Minnesota
Title: Linking oxide surface composition, strain, and structure to reactivity
Abstract: Many ceramic oxides can undergo redox processes at their surface when exposed to gases (e.g. O2, H2O), where the resultant changes in surface chemistry can have notable effects on functional properties. Probing the surface of such materials in situ provides a key understanding of the extent to which such transformations occur, and in some cases, the kinetics of redox processes. We employ a variant of X-ray photoelectron spectroscopy (XPS) that enables this surface science technique—typically limited to ultrahigh vacuum conditions—to reach nominally ambient pressures in order to probe the surface of ceramic oxides in equilibrium with gaseous O2 and H2O. We identify and quantify surface adsorbates and corresponding changes in transition metal valence, elucidating relationships between the local atomic environment and chemical reactivity. We leverage epitaxial films in order to control the crystallographic orientation of oxide ceramics and investigate the impact of strain on surface redox processes, providing quantitative insight into the surface species present and depth of redox processes at a given temperature and pressure. These investigations establish how changes in materials structure influence the reactivity with molecules such as water.
For more information, visit the AEM Mechanics Research Seminar website:
Tuesday 02-Sep-2025, 12:20pm Central
In-person: Room 313, Akerman Hall, University of Minnesota
Online: Webinar registration link
Department of Chemical Engineering and Materials Science, University of Minnesota
Title: Linking oxide surface composition, strain, and structure to reactivity
Abstract: Many ceramic oxides can undergo redox processes at their surface when exposed to gases (e.g. O2, H2O), where the resultant changes in surface chemistry can have notable effects on functional properties. Probing the surface of such materials in situ provides a key understanding of the extent to which such transformations occur, and in some cases, the kinetics of redox processes. We employ a variant of X-ray photoelectron spectroscopy (XPS) that enables this surface science technique—typically limited to ultrahigh vacuum conditions—to reach nominally ambient pressures in order to probe the surface of ceramic oxides in equilibrium with gaseous O2 and H2O. We identify and quantify surface adsorbates and corresponding changes in transition metal valence, elucidating relationships between the local atomic environment and chemical reactivity. We leverage epitaxial films in order to control the crystallographic orientation of oxide ceramics and investigate the impact of strain on surface redox processes, providing quantitative insight into the surface species present and depth of redox processes at a given temperature and pressure. These investigations establish how changes in materials structure influence the reactivity with molecules such as water.
For more information, visit the AEM Mechanics Research Seminar website:
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Ellad B. Tadmor, Ph.D.
Russell J. Penrose Professor
Department of Aerospace Engineering and Mechanics
University of Minnesota
https://dept.aem.umn.edu/~tadmor/
Russell J. Penrose Professor
Department of Aerospace Engineering and Mechanics
University of Minnesota
https://dept.aem.umn.edu/~tadmor/
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