Abstract

The morphology of Pd-based catalysts used on methane combustion was studied. The supports were prepared by combustión synthesis and the effects of the addition of cerium and lanthanum were analyzed. The morphology stability was followed by SEM. The micrographs revealed that the basic morphology of alumina is retained even after lanthanides addition. A process of grain separation was observed on both alumina and cerium-containing powder when treated at 1200 °C. Such a process is only significant at 1300 °C for the lanthanum loaded sample. A model in which CeCL small crystals are deposited on a-APOi is suggested to describe the powder. Lanthanum compound seems to create a distinct phase with aluminum, which presents a slower grain separation process. The results also show that this process is catalyzed by Pd, which is located on the supports grains boundaries.