Spectroelectrochemical measurement of chemical reaction rates. First-order catalytic processes

The technique of in situ spectral monitoring of intermediates or products of an electrode process using optically transparent electrodes (ote) provides the opportunity of evaluating the kinetic rates for a wide variety of mechanisms. In this paper the technique has been applied to a catalytic reaction scheme in which the electroactive species originally present is regenerated by a pseudo-first-order homogeneous chemical reaction. Theoretical expressions relating the light absorbance of the electrode reaction product to kinetic parameters have been derived for conditions of single and double potential step electrochemical modes. The experimental test was provided by the electrooxidation of ferrocyanide in the presence of ascorbic acid at tin oxide ote.