(Invited) Probing Surface and Bulk States of Cathode Materials with Synchrotron-Based Soft X-Rays in a Functioning Solid Oxide Fuel Cell

Abstract

We discuss the development of a research platform designed to investigate surface and bulk properties of electrocatalysts in an operating solid oxide fuel cell using synchrotron-based soft X-ray spectroscopies. This novel platform realizes a fully functioning galvanic cell capable of supporting a Nernst potential, and incorporates both ambient pressure X-ray photoemission and X-ray absorption spectroscopies. Thus, surface compositions, surface electronic states, and bulk electronic states can be measured while manipulating the electrode environment; i.e., varying the gas composition, pressure, temperature, and cell potential. We will demonstrate the utility of this approach by presenting results of an experimental campaign focused on understanding what gives rise to the enhanced oxygen reduction reaction rates observed on a Ba0.5Sr0.5Co0.8Fe0.2O3 perovskite cathode.