Novel Ru/La0.75Sr0.25Cr0.5Mn0.5O3-δ catalysts for propane reforming in IT-SOFCs

The La0.75Sr0.25Cr0.5Mn0.5O3-delta (LSCM) catalyst and the novel Ru/La0.75Sr0.25Cr0.5Mn0.5O3-delta composite were investigated as alternative anodes for the direct utilization of propane in anode-supported solid oxide fuel cells. In particular, their synthesis and performance in direct propane reforming were studied. The LSCM powders were prepared by a sol-gel method based on a modified Pechini procedure. Single-phase LSCM perovskite powders were obtained. SEM micrographs of the LSCM powders revealed particles in the 200-300 nm range with a homogeneous grain distribution. The deposition of 5 wt.% metallic ruthenium nanoparticles on the LSCM perovskite powders was carried out by a microwave-assisted procedure. TEM investigations of Ru/LSCM composites showed a homogeneous distribution of metallic ruthenium nanoparticles with a mean grain size of around 2-3 nm. The catalytic activity of these potential anode materials was investigated for the following propane reforming processes: steam reforming (SR), autothermal reforming (ATR) and partial oxidation (POX) at 600,700 and 800 degrees C. Very high propane conversion rates were observed under POX and ATR conditions at 700 and 800 degrees C for both the LSCM and Ru/LSCM compounds (>92 at 700 degrees C and >98% at 800 degrees C), whereas in the steam reforming environment, a satisfactory conversion was achieved only at 800 degrees C. The ruthenium presence was found to strongly improve the selectivity for H-2 and syngas production for all of the experiments performed, reaching an approximately 90% syngas yield. Finally, good chemical stability after the catalytic tests was demonstrated for the LSCM and Ru/LSCM anode materials. (C) 2010 Elsevier B.V. All rights reserved.