Lecture: Oxygen surface exchange kinetics of mixed ionic-electronic conducting oxides

Lecturer:  Prof. J.M. Bouwmeester

Time: 9:00 am, October 25, 2019, Friday

Location: 216 Meeting Room, Energy Building

Introduction of Lecturer: 

Henny J.M. Bouwmeester heads the Electrochemistry Research group, part of the Membrane Science Technology cluster, at the University of Twente, Enschede, The Netherlands, and is part-time professor at the University of Science and Technology of China (USTC) in Hefei, China. In 2018, he joined the Gas Separation Membranes Department, Institute of Energy and Climate Research (IEK-1), Forschungzentrum Jülich, Germany, as a guest scientist. Prof. Bouwmeester’s research interests include physical chemistry of solids, thermodynamics, ionic transport and interfacial/electrode kinetics, closely related to applications such as oxygen transport membranes, solid oxide fuel cells, solid oxide electrolysis cells and sensors. In these fields, he has authored and co-authored several book chapters and more than 150 research papers (h-index 50 Web of Science). He serves and served as a member of the board or council of several societies and international conferences. He is co-editor of the CRC’s Handbook of Solid State Electrochemistry and is topical editor of the Journal of Solid State Electrochemistry.

Abstract: 

High-temperature electrochemical devices such as solid oxide fuel cells, solid oxide electrolysis cells, oxygen separation membranes and membrane reactors based upon fast oxygen ionic conducting oxides have the potential to provide great economic and ecological benefits. One of the challenges of researchers in this field is to develop materials showing fast oxygen ionic transport and fast surface exchange kinetics under given operating conditions. It is therefore important to gain a fundamental understanding of the factors controlling oxygen surface exchange, such as defect chemistry and defect-related properties, degree of oxygen non-stoichiometry, surface composition and grain boundary properties.

Currently, main characterization methods used to determine the oxygen surface exchange kinetics of fast ionic conducting oxides include 18O-16O isotopic exchange depth profiling method (IEDP), 18O-16O isotopic exchange gas phase analysis (IE-GPA), 18O-16O isotopic exchange pulse technique (PIE), electrical conductivity relaxation (ECR), electrochemical impedance spectroscopy under controlled atmosphere (humidity and pO2). Data from, e.g., low energy ion scattering (LEIS) and X-ray photo electron spectroscopy (XPS) is used to relate the observed oxygen exchange kinetics to the surface and near-surface composition of the materials.

Major aim of my lecture is to present methods used in studies towards understanding the oxygen surface exchange kinetics of single-phase and composite mixed ionic-electronic conducting oxides, recent progress and challenges.