Investigation of the B-site stability of LSCF perovskites for ammonia-fueled SOFCs by APXPS and NEXAFS

Ammonia-fueled solid oxide fuel cells (SOFCs) have been claimed as a carbon-free alternative for direct conversion of chemical energy into electricity in a single step. Traditional SOFC’s rely on Ni-based catalysts, which provides high selectivity for ammonia cracking but still present challenges preventing their implementation. La1-xSrxCo1-yFeyO3-δ (LSCF) perovskites have been proposed as promising catalysts as both anodes and cathodes due to their wide range of tunable electrical, thermal and catalytic properties. In addition, they shift the selectivity towards NO, which offers the possibility to not only to generate electricity but also to produce a valuable chemical intermediate for nitric acid synthesis. However, there is a lack of studies on their phase, structure and chemical composition in reducing atmospheres and their performance in ammonia oxidation. While Co enhances the activity, it tends to be reduced under operating conditions, negatively affecting stability. This study aims to investigate the stability of La0.6Sr0.4Co1-yFeyO3-δ (LSCF) perovskites as anodes and/or cathodes of ammonia-fueled solid oxide fuel cells (SOFC) under typical NH3 oxidation conditions, monitoring structural transformations and cobalt reducibility. Near-ambient pressure x-ray photoelectron spectroscopy (NAP-XPS) can provide a powerful tool for analyzing the surface stability and transformations of these materials under relevant conditions. A deeper understanding of these changes will provide crucial surface-sensitive insights and will help us find alternatives for enhancing stability, optimizing the composition of LSCF perovskites for NH3-SOFCs.