The complete oxidation of hydrocarbons (methane, propane and propene) and the O-18/O-16 isotopic exchange were investigated on supported palladium-platinum catalysts. The bimetallic catalysts were prepared by controlled surface reactions (the "refilling" RC and the "direct redox reaction" RD) and by coimpregnation CI. The preparation methods lead to different kinds of platinum deposit, which involve different behaviours in hydrocarbon oxidation and in isotopic exchange. Even if the structure of bimetallic catalysts is modified under oxygen, the results show that the bimetallic catalysts keep a memory effect of their preparation method under the reaction conditions used in this work.