Nanostructured platinum (H-I-ePt) films: Effects of electrodeposition conditions on film properties

A systematic investigation into the effects of deposition conditions on the electrochemical properties and nanostructure of high surface area (up to s imilar to 460 m(2) cm(-3)) mesoporous platinum films (H-I-ePt) obtained by electroreduction of hexachloroplatinic acid (HCPA) from an hexagonal lyotro pic liquid crystalline phase is reported. The surface area, repeat distance , and regularity of the nanostructure and the surface morphology of the fil ms were shown to depend on the deposition conditions. In particular, the de position potential was found to have a notable effect on the film surface a rea and on the uniformity of nanostructure, The results obtained are explai ned by variations in the efficiency of the deposition process and the relat ive contributions of competing reactions. Increasing the temperature of ele ctrodeposition was found to increase significantly the surface areas of the films and to increase the repeat distance of the nanostructure, In additio n, a roughening of the films on both a micro- and a nanometer scale was obs erved with an increase in temperature. We also found that the thickness of the electrodeposited films scaled linearly and that the volumetric surface area was constant, with the charge passed during the electrodeposition proc ess, indicating uniform accessibility of the pore system.