Dresden 2026 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 52: Oxide and insulator surfaces: Structure, epitaxy and growth I

O 52.4: Vortrag

Dienstag, 10. März 2026, 15:30–15:45, WILL/A317

Atomic-scale effects of surface modifications on mixed conducting oxides — •Matthäus Siebenhofer, Claudia Steinbach, and Jürgen Fleig — TU Wien, Institute of Chemical Technologies and Analytics, Vienna, Austria

Mixed ionic and electronic conducting (MIEC) oxide surfaces play a critical role in various technologies due to their high catalytic activity for processes such as oxygen reduction, oxygen evolution, and (photo)electrochemical water splitting. Recent advances have shown that even minute amounts of surface modifications can dramatically alter the work function and the catalytic performance but the detailed mechanisms behind these effects remain poorly understood.

This contribution discusses our efforts to understand the fundamental processes that occur during modification of MIEC oxide surfaces with ultra-thin oxide layers and acidic contaminants. We employ in-situ impedance spectroscopy during pulsed laser deposition (i-PLD) to monitor changes in the oxygen exchange activity of pristine thin film surfaces; X-ray photoelectron spectroscopy (XPS) and density functional theory (DFT) provide insights into atomic-scale processes induced by these modifications.

Our results demonstrate that surface modifications introduce charge redistribution between the modification and the MIEC oxide. These effects are governed by the ionic potential and acidity of both the host material and the modifying species. Based on these observations, we provide design strategies to tailor optimized material combinations for targeted catalytic applications.

Keywords: surface modifications; oxygen exchange; thin films; work function; defect chemistry