Electrocatalytic oxidation of benzyl alcohol in alkaline medium on RuO₂-coated titanium electrode

The heterogeneous electrocatalytic redox behaviour of RuO₂ electrodes fabricated by thermal decomposition is investigated with and without benzyl alcohol using cyclic voltammetric and potentiodynamic techniques. The cyclic voltammetric results show that benzyl alcohol oxidation is mediated by perruthenate ion electrogenerated at the electrode surface. Evaluation of kinetic parameters in relation to Tafel lines allows the postulation of a plausible reaction scheme in which benzyl alcohol adsorbs on the RuO₂ electrode surface and the rate determining step is chemical reaction between perruthenate and adsorbed species. The reaction orders with respect to benzyl alcohol and OH^- concentrations are 0.85 and 1, respectively. The results in galvanostatic electrolysis show that the major product for benzyl alcohol oxidation in an aqueous solution is benzaldehyde, and the organic yield is affected by such electrolysis conditions as t-butanol concentration, electrolysis current density, KOH concentration and electrolysis temperature.