Event Type:
MSE Grad Presentation
Date:
Talk Title:
Development of Model Cells for Characterizing Electro-Catalysts in Solid Oxide Cells
Location:
J. Erskine Love Room 183

Committee

Prof. Meilin Liu – School of MSE (advisor)
Prof. Preet Singh– School of MSE
Prof. Hamid Garmestani – School of MSE

Abstract:

Solid oxide fuel cells (SOFCs) are a type of fuel cell technology that has offers several outstanding characteristics including high efficiency, reversible operation, and mechanical robustness. However, their development is hindered in large part by the relatively slow kinetics on the air electrode surface. To address these challenges, considerable research is being directed towards uncovering high-performance catalysts for the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) pathways.

Conventional cells for operational testing have porous electrodes that maximize the available surface area for these reactions to take place. Catalyst candidate materials applied to these electrodes ideally are dispersed in a thin and uniform coating over the porous electrode backbone. This microstructure yields the best cell performance, but it can be difficult to characterize the surface chemistry due to the thinness of the catalyst layer and how a majority of the catalyst material is blocked from direct exposure of techniques such as Raman spectroscopy and XPS. Model cells are a cell design where one of the porous electrodes is replaced with a thin and fully dense electrode that can then be coated with a catalyst layer. While the electrochemical performance of such a cell may be lower, the advantage of this design is that the reaction space is confined to well-defined plane at the surface of the cell which is easily probed.

In this work, I outline the important criteria for a model cell design that would be suitable for use in screening promising catalyst material compositions for both performance enhancement as well as chemical stability in typical SOFC operating conditions. Furthermore, I discuss the detailed fabrication procedure used to produce said cells in a repeatable manner and in sufficient quantity to carry out catalyst screening. I then present some specific findings that demonstrate the capability of these model cells in enabling catalyst investigation that combines electrochemical performance data with surface chemistry measurements to gain a deeper insight into the mechanisms behind catalytic enhancement and stability that can guide future rational design of promising catalyst materials.