The catalytic activity of distinct sulphur adlayers on polyoriented Pt has been tested with regard to SO2 oxidation by means of cyclic voltammetry. A full monolayer of sulphur - on which the adspecies distributes following a two-site adsorption geometry on average does not exhibit the most enhancing properties. A highly catalytic layer yields a sulphur oxidation charge within the bilayer level. An excessive deposition of sulphur leads to loss of the catalytic activity.