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The first paper in this series (i) developed a theoretical model for characterizing the charging currents induced by changing faradaic currents measured under potentiostatic conditions. This paper describes application of the theoretical model to measurements involving electrolysis mechanisms complicated by competing reactions. The model is particularly relevant for flash photoelectrochemical studies. The mechanisms considered here include first order and second order decay of electroactive photoproducts. The dependence of measured currents on various experimental and chemical parameters--including the cell time-constant, photoproduct concentrations, and rate constants--is described for a wide range of conditions. Theoretical relationships can be used to predict total measured currents, or to tabulate correction factors to extract purely faradaic currents from measured currents. In addition, an alternative derivative-correction method for extracting faradaie signals from combined currents is described.

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A photoelectrochemical technique has been applied to the study of the photoreduction of Co(NH3)63+ in the presence of benzophenone. Currents due to the oxidation of benzophenone ketyl radical and the reduction of the Co(III) complex were monitored after flash irradiation. In basic alcoholic solution the initial amount of ketyl radical produced by the flash was significantly diminished in the presence of Co(III) complex. Also, the amount of Co(III) complex seen after the flash was lowered substantially in the presence of benzophenone. The reactivity of Co(III) and ketyl radical when both are present after a flash appears negligible, failing to account for the significant photoreduction observed immediately after the flash. These data suggest that the primary reaction pathway involves energy transfer from the excited benzophenone triplet to the Co(III) complex with subsequent decomposition to the Co(II) product. In acidic solution (pH 5.5), no significant sensitized photoreduction of the Co(III) complex was observed.