A new electrochemical procedure to obtain platinum electrode surfaces with preferred orientations from bulk polycrystalline platinum is presented. The procedure invo!vrs the application of repetitive potentiai sweeps al high Frequrncie s to a polycrystalline platinum electrode under carefully selected potential perturbation condirions. The electrochemical response of the surrnce structures achieved after the treatment approach closely those repor:-d in the literature for determined types of platinum single crystal faces. wit:1 2 relatively well-defined .surface structure. Obviously, the development of electrochemical techniques to manage the elec-0322-0728/85/SO3.30 0 1985 Elsevier Sequoia S.A.

Scanning electron micrographs are taken for a polycrystalline platinum wire before and after the application of a repetitive potential scan at more than 10,000 V/s. The change of the surface structure observed is related to a specific hydrogen adatom voltammogram usually obtained for single crystal surfaces.

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The Kolbe electrosynthesis on polycrystalline platinum in 1 M acetic acid/l M potassium acetate electrolyte at 30 o C was studied by using potentiostatic, low-frequency potentiodynamic and impedance techniques. Reaction products and their distribution as a function of potential were determined. There is a good correspondence in the potential ranges where changes in both stationary and non-stationary kinetic data, electrode resistance, electrode capacitance and reaction products were found. Results confirm the existence of different electrochemical reactions and correspondingly different reaction intermediates in the various Tafel regions.