The influence of the support has been tested on the reactivity of Pd/rare earth oxides catalysts (La{sub 2}O{sub 3}, CeO{sub 2}, Pr{sub 6}O{sub 11}, Nd{sub 2}O{sub 3}, Tb{sub 4}O{sub 7}). According to BET surface area, chemisorption, temperature-programmed reduction (TPR) and oxidation (TPO), x-ray diffraction (XRD) and x-ray photoemission (XPS) characterizations, these catalysts have been classified into three classes according to their ability to create anion vacancies: (i) oxides of the type Re{sub 2}O{sub 3} which are unreducible, (ii) CeO{sub 2} where anion vacancies can be created extrinsically by the reduction process, and (iii) Pr{sub 6}O{sub 11} and Tb{sub 4}O{sub 7} where anion vacancies exist due to the nonstoichiometric nature of these oxides. The authors emphasize also the role of chlorine, coming from the palladium precursor salt, which reacts with the support to form a stable oxychloride phase surrounding the metallic particle and interacting with it. Concerning the catalytic activity, (i) the active site is purely metallic in methylcyclopentane hydrogenolysis, with small selectivity changes on fluorite oxides as compared to Pd/Al{sub 2}O{sub 3} catalysts due to some electronic interaction with the support, but (ii) the mechanism is found to be partly bifunctional in 3-methylhexane aromatization with a large increase in aromatizationmore » on Pr{sub 6}O{sub 11} and Tb{sub 4}O{sub 7} supports, and (iii) in syngas conversion, production of high alcohols occurs at the metal-support interface and is favored by the presence of intrinsic anion vacancies on Pr{sub 6}O{sub 11} and Tb{sub 4}O{sub 7} supports.« less