Interaction between palladium and the support in Pd/CeO2 prepared by deposition-precipitation method and the catalytic activity for methanol decomposition

Adsorption of carbon monoxide on cerium oxide at room temperature can proceed over 3 wt.% Pd/CeO2 prepared by a deposition-precipitation method. The quantity of carbon monoxide adsorbed is largely excessive to the content of palladium in the sample while the amount of carbon monoxide adsorbed on 3 wt.% Pd/CeO2 prepared by the conventional impregnation technique is small. The catalyst prepared by deposition-precipitation is highly active for the methanol decomposition to carbon monoxide and hydrogen at 160 degrees C-220 degrees C compared with the impregnated sample. Analyses by XPS show presence of cationic palladium species in the former catalyst after the reaction while only metallic species can be found in the latter, appearing that there is strong interaction between the palladium species and the support in the catalyst prepared by deposition-precipitation. (C) 2000 Elsevier Science B.V. All rights reserved.