Electrocatalysis with modified gold electrodes towards sodium dithionite

4 Electrocatalysis with modified gold electrodes towards sodium dithionite 

Despite the fact that, for the oxidation of sodium dithionite at unmodified gold electrodes, well-defined voltammetric waves are obtained12, the reaction still behaves irreversibly1214. Therefore, it is in principle possible to improve the oxidation rate of this reaction by using an appropriate catalyst immobilised at the gold electrode surface. The modified electrode used here was obtained by a 100-fold scanning experiment between -1.2 and 

6 (a) Molecular structure of cobalt(ll)tetrasulphonated-phthalocyanine, sodium salt (b) 5,10,15,20-tetrakis-(4-sulphonatophenyl) porphyrin cobalt (II), tetrasodium salt. 

In Fig. 7.7, cyclic voltammetric curves are shown of the oxidation of sodium dithionite at a gold electrode (curves 1,4), at a CoTSPc-modihed gold electrode (curves 2, 5) and at a CoTSPor-modihed gold electrode (curves 3, 6) for two different sodium dithionite concentrations. Several observations indicate electrocatalytic behaviour. First, the voltammetric waves are shifted towards less-positive potentials. This means that less 

Another remark is the relatively mild electrocatalytic effect resulting in a shift of the wave of 20 mV and an increase of the peak currents by approx- 

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