Microelectrodes as probes in low electrolyte solutions: the reduction of quinone in aqueous sulfuric acid solution


The steady-state voltammetric behavior of quinone in dilute aqueous solutions of sulfuric acid has been investigated at platinum disk microelectrodes and compared with the model presented by Oldham (J. Electroanal. Chem., 250 (1988) 1). At high concentrations of sulfuric acid, a single voltammetric wave whose limiting current is predicted by Oldham's model is observed. As the concentration of the sulfuric acid is lowered relative to that of the quinone, the single voltammetric wave splits into two waves. The first wave is due to the two-electron reduction of quinone in acidic solution and the magnitude of its limiting current agrees with that predicted by Oldham's model. The second wave also results from the reduction of quinone but occurs at a more negative potential owing to the change in pH at the electrode surface. Such a process was not considered in Oldham's model. © 1994.

Publication Title

Journal of Electroanalytical Chemistry