Effect of the Reduction Step on the Catalytic Performance of Pd–CeMO2 Based Catalysts (M 5 Gd, Zr) for Propane Combustion
Résumé
The effect of a reduction step on the catalytic
activity of Pd supported doped ceria catalysts was investigated
for the propane combustion. Two different oxides
based on ceria zirconia (CZ), as a reference three-way
catalyst support, and Gadolinia doped ceria (GDC), a
mixed ionic electronic conductor, have been used to support
Pd nanoparticles. The samples were characterized by
H2–CO chemisorption, temperature programmed reduction,
and XPS. In addition, the reduction step in H2 was
in situ observed by environmental transmission electron
microscopy. It was found that the catalytic activity of Pd
supported on ceria-based supports can be strongly promoted
by a reduction step whereas it does not change on
alumina. This effect was attributed, in particular on GDC,
to the reduction of a surface interaction phase, PdxCeO2-d,
which induces a re-dispersion of metallic Pd nanoparticles.