CARBON-MONOXIDE ADSORPTION ON PD CEO2 CAT ALYSTS - AN FTIR STUDY OF CARBONYL CLUSTERS/

Pd/Al2O3 and Pd/CeO2 catalysts were prepared by an impregnation proced ure. The FT-IR study of the CO adsorption evidenced that palladium is in a more dispersed state when the carrier is reducible (ceria) than i n the non-reducible case (alumina). On the ceria carrier palladium for med compact two-dimensional crystallites. The CO adsorption at room te mperature on these crystallites was the more corrosive as the reductio n temperature was low. Adsorbed carbonyl complexes were then observed with the following v(CO) wavenumbers : Pd(CO) (2010 cm(-1)), Pd2CO (19 60 cm(-1)) and Pd-2(CO)(2) (1987, 1927 cm(-1)). They were only transie nt species when observed on the unreduced Pd/CeO2 catalyst.