Superior Oxygen Reduction Performance and Stability of SOFC Cathodes via RF-Sputtered Ruthenium Electrocatalysts

Enhancing the oxygen reduction reaction (ORR) kinetics is crucial for improving the electrochemical performance of solid oxide fuel cells (SOFCs). Various strategies have been explored to modify state-of-the-art ion-conducting cathode scaffolds by incorporating electrocatalysts to create synergistic effects. In this study, we utilize radio frequency (RF) sputtering to integrate platinum (Pt) and ruthenium (Ru) electrocatalysts into gadolinium-doped ceria (GDC) scaffolds, aiming to enhance ORR kinetics. Electrochemical analyses reveal that Ru-sputtered electrocatalysts exhibit superior catalytic activity and long-term stability compared to Pt-sputtered counterparts. Postmortem analysis using energy-dispersive spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS) identifies Pt agglomeration as the primary cause of its poor stability. In contrast, Ru undergoes an in situ transformation into a stable, needle-like RuO 2 phase during operation, significantly improving durability. The RF sputtering approach presents a simple, cost-effective method for deploying highly efficient and thermally stable Ru electrocatalysts, offering a viable pathway toward the commercial realization of high-performance SOFCs.