Analytical theoretical framework for closed bipolar electrochemical cells under homogeneous molecular catalysis: Implications for electrochemiluminescence applications

A novel analytical framework has been formulated to describe the current-potential-time response in systems with two polarized interfaces where one charge transfer process follows a catalytic mechanism, as found in co-reactant electrochemiluminescence (ECL) systems. The developed theory provides mathematical expressions for electrochemical and ECL signals, concentrations, and interfacial potentials upon the application of a constant potential pulse. Theoretical analysis reveals that the chemical regeneration of the redox reactant within the catalytic cycle has a remarkable impact on the chronoamperometric, voltammetric, and ECL responses, thereby providing means to estimate the catalytic rate constant and to optimize light emission. The system's behaviors are rationalized through the influence of catalysis on the interfacial concentrations and potentials. Also, the primary theoretical predictions have been experimentally validated using the [Ru(bpy)₃]²⁺/oxalate ECL system.