In this review, results obtained in this laboratory concerning the hyd
rogenation of a diolefine (1,3-butadiene) and of an unsaturated aldehy
de (3 methyl, crotonaldehyde) on platinum single crystals are summariz
ed. The influence of the surface structure on the catalytic activity a
nd selectivity is discussed by referring mainly to the various adsorpt
ion modes of the organic molecule.