On the voltammetric behavior of a platinized titanium surface with respectto the specific hydrogen and anion adsorption and charge transfer processes

The procedure for obtaining platinized titanium (Pt/Ti) electrodes has been optimised in order to avoid the contamination produced by the presence of chloride anions and other impurities and the formation of titanium oxide on the titanium surface. It has been demonstrated that the surface preparatio n of the titanium substrate and the washing procedure are crucial steps for obtaining Pt/Ti electrodes with hydrogen adsorption-desorption behaviour s imilar to that of polycrystalline platinum electrodes. The plating bath is a solution of H2PtCl6 (1.79 dm(-3) of platinum at pH lower than 1). The dep osition process is carried out at a constant current density of 5 mA cm(-2) for 100 min and at a temperature of 90-95 degrees C. Under these condition s, deposits with a thickness of 5-10 mu m are obtained. The roughness facto r of the Pt/Ti electrode is approximately 125.