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

The La0.75Sr0.25Cr0.5Mn0.5O3-d (LSCM) catalyst and the novel Ru/La0.75Sr0.25Cr0.5Mn0.5O3-d 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), auto-thermal reforming (ATR) and partial oxidation (POX) at 600, 700 and 800 °C. Very high propane conversion rates were observed under POX and ATR conditions at 700 and 800 °C for both the LSCM and Ru/LSCM compounds (>92 at 700 °C and >98% at 800 °C), whereas in the steam reforming environment, a satisfactory conversion was achieved only at 800 °C. The ruthenium presence was found to strongly improve the selectivity for H2 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.