HYDROGEN DEACTIVATION OF SPUTTER-DEPOSITED PLATINUM THIN-FILMS ON HIGHLY ORIENTED PYROLYTIC-GRAPHITE

Electrochemical techniques such as chronopotentiometry and a.c. impeda nce spectroscopy have been used successfully to characterise the behav ior of sputter-deposited platinum on highly oriented pyrolytic graphit e (HOPG) substrate under hydrogen evolution reaction (HER) in 1 M NaOH at 25 degrees C. Prior to the sputtering process, HOPG surfaces were etched up to 60 min and deposition time was varied up to 20 min. Under a constant applied current density, the rate of overpotential increas e with time and its magnitude are strongly related to the experimental conditions during the electrode preparation. Deactivation during HER is attributed to a loss of sputtered platinum due to its poor adhesion to the substrate. (C) 1997 International Association for Hydrogen Ene rgy.