Electrochemical investigation of a propane-fed solid oxide fuel cell based on a composite Ni–perovskite anode catalyst

A composite Ni–perovskite anode was investigated for operation in dry propane-fed intermediate temperature solid oxide fuel cells (IT-SOFC). A La0.6Sr0.4Fe0.8Co0.2O3 (LSFCO) perovskite, characterized by mixed electronic–ionic conductivity, was used to support a highly dispersed Ni-phase. However, the catalyst structure was modified during SOFC operation. X-ray diffraction analysis of the electrocatalyst showed that, after operation, Ni was mainly present as La2NiO4; whereas, the LSFCO structure was partially modified into a lanthanum-depleted SrFe1−xCoxO3−y (SFCO) perovskite structure. These results were corroborated by X-ray photoelectron spectroscopy (XPS). Transmission electron microscopy (TEM) analysis showed the presence of a suitable dispersion of a nanosized Ni-phase and a strong interaction of Ni-enriched particles with the perovskite substrate. High reaction rates for the propane reaction were achieved with this electrocatalyst while minimizing carbon deposition. Power densities of about 300 mW cm−2 for dry propane oxidation were obtained at 800 °C in the presence of a thick gadolinia-doped ceria electrolyte. Fuel cell time-tests indicated promising electrochemical stability.