A NEW SIMPLE VOLTAMMETRIC ANALYSIS OF THE KINETICS OF HOMOGENEOUS REACTIONS FOLLOWING THE EC MECHANISM - OXIDATION OF CU(I) BY HYDROGEN-PEROXIDE

A new method for the calculation of rate constants of homogeneous reac tions following an electron transfer step (the so called EC or electro chemical-chemical mechanism) is presented. It is shown that the diffus ion problem for cyclic voltammetry for an EC mechanism has an analytic al solution for a fast electron transfer reaction and an irreversible subsequent homogeneous reaction, provided the concentration of electro active species does not change considerably during the voltammetric sc an. This condition corresponds to analysing the voltammogram for curre nt densities far below the peak current density. It is shown that the rate constant can be easily derived from the sweep rate at which no cu rrent minimum is observed in the reverse sweep. The rate constant for the reaction between Cu(I) and H2O2 has been measured with this techni que and a value of (75+/-10) dm(3) mol(-1) s(-1) has been found.