Reduction of an ensemble of chloride aquacomplexes of platinum(II): An analysis in the framework of phenomenological approach

A general approach is offered to a phenomenological analysis of experimental data on the kinetics of an electrode reaction complicated by chemical stages. The approach is based on a consideration of the way the process rate depends on the supporting-electrolyte concentration at a constant electrode charge. The possibilities of the approach are illustrated by the example of the reduction of chloride complexes of Pt(II) in the presence of chloride, indifferent (in the sense of inner-sphere substitution), and mixed supporting electrolytes. The performed analysis generalizes the Frumkin-Petrii relationship, which determines the average charge of the single reactant in the solution bulk. A system map contain an ensemble of reactants. In this case, in addition to the bulk properties of the system, similar relationships take into account the interface structure and the balance between partial rate constants for parallel reactions involving reactants of different chargeness.