Toward Stabilizing Co 3 O 4 Nanoparticles as an Oxygen Reduction Reaction Catalyst for Intermediate-Temperature SOFCs

Abstract

© The Author(s) 2017. The oxygen reduction reaction (ORR) activity of a series of composite cathodes consisting of a porous Gd 0.20 Ce 0.80 O 2-δ (GDC) scaffold infiltrated with Sr-, Co-, and Y-nitrate solutions has been systematically investigated in this study. The results show that such infiltrated cathodes if calcined at low temperatures such as 350°C exhibit low polarization resistance (R P ) in the temperature range of 450-700°C, even though XRD analysis reveals that the calcined product is virtually a mixture of Co 3 O 4 and SrCO 3 . A further study by design-of-experiment suggests that the true ORR-active species is Co 3 O 4 , whereas SrCO 3 serves as a sintering inhibitor to preserve the high surface area of Co 3 O 4 . The findings and understanding in this study present a new strategy for future development of active cathodes for intermediate-temperature solid oxide fuel cells (SOFCs).