Study of Ce-Cu mixed oxide catalysts by in situ electrical conductivity measurements

摘要

Three Ce-Cu mixed oxides, namely Ce0.95Cu0.05, Ce0.6Cu0.4 and Ce0.15Cu0.85, along with pure CeO2 and CuO were characterized by in situ electrical conductivity measurements. Their electrical conductivity was studied as a function of temperature and oxygen partial pressure, and was followed with time during successive exposure to air, nitrogen and different gaseous mixtures containing propane as a VOC model molecule, under conditions close to those of their catalytic applications. CeO2 and CuO appeared to be n-type and p-type semiconductors, respectively, while the semiconducting behavior of the Ce-Cu mixed oxides depended on the oxide composition. The semiconductive and redox properties of the samples were correlated with their catalytic behavior in CO oxidation, ethene total oxidation and soot combustion.