Synthesis and characterization of a doubleperovskite anode for solid oxide fuel cells

Abstract

Solid oxide fuel cells are one of the most efficient devices for the direct conversion of the chemical energy of a fuel into electricity. Nonetheless, standard solid oxide fuel cells (SOFC) with Ni/yttria-stabilized zirconia cermet anode have a serious decrease of their lifetime when fed with carbon-containing fuels due to coke formation. Ceramics with perovskite structure have been pointed out as good candidates to anodes. In this study, the Pr0.5Ba0.5MnO3 was used as the precursor phase of the double perovskite PrBaMn2O5+δ (PBMO), present at reducing conditions. The transport and catalytic properties were studied in the pristine compound and in Ru-doped samples Pr0.5Ba0.5Mn1-xRuxO3 (Ru-PBMO). Ru substitution at the B-site is expected to enhance the catalytic properties of the ceramic toward ethanol for SOFC’s running on such fuel. Simultaneous thermogravimetric and differential thermal analysis (TG/DTA) were used to monitor the thermal evolution of polymeric resins up to 1400 °C. Ceramic powders were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analyses. The electrical properties of sintered samples were evaluated by dc 4-probe technique, in the 25 - 800 °C temperature range. The TG/DTA and XRD data show mass loss stabilization and crystalline phase formation occurring at ~800°C. The evolution of the XRD pattern upon calcining temperature indicated the formation of single phase of Ru-PBMO samples at ~1100°C. The initial results suggest that PBMO and PBMO-Ru compounds are promising SOFC anodes for carbon containing fuels.