In an attempt to contribute to the understanding of the behaviour of oxide monolayer formation and dissolution on polished platinum electrodes, those processes were studied in molten sodium bisulphate-potassium bisulphate at 184°C, using linear single-sweep voltammetry with different potential-time profiles. The electrode roughness factor, as obtained from the charge related to the hydrogen reduction in aqueous sulphuric acid, was 1.6.