VOLTAMMETRIC AND IMPINGING JET STUDY OF THE BEHAVIOR OF RHODIZED ELECTRODES IN ACIDIC PERCHLORATE SOLUTIONS

The reduction of ClO4- ions in acid media was studied at rhodized elec trodes (roughness factor values of about 100-200) by voltammetric and hydrodynamic (impinging jet) methods. The effect of HClO4 concentratio n and the influence of pH (at a fixed ionic strength) on the shape of the voltammetric curve was investigated and interpreted. The inhibitio n of the reduction process by adsorbing anions, first of all by Cl- io ns produced by reduction, was demonstrated. It has been stated that re liable information concerning the laws governing the reduction process cannot be obtained from voltammetric measurements alone. As an additi onal tool, a version of the impinging jet technique was used to find a relationship between the potential E of the rhodized electrode and th e reduction rate I. A characteristic, almost symmetric, /I/ versus E c urve going through a maximum was obtained from the experimental data. Reduction mechanisms were suggested for the interpretation of the expe rimental results. The reaction rate versus potential curves calculated on the basis of model assumptions were compared with the experimental data.