Electrochemical oxidation of ethanol using Nafion electrodes modified with heterobimetallic catalysts

Chemically modified electrodes were prepared by adsorption of Nafion/catalyst films of the type Nafion/Cp(PPh3)Ru(μ-I)(μ-dppm)PdCl2 (N1), Nafion/[η5-C5H4CH2CH2(NHMe2)+]Ru(PPh3)(μ-I)(μ-dppm)PtCl2 (N2), Nafion/[η5-C5H4CH2CH2(NHMe2)+]Ru(PPh3)(μ-Cl)(μ-dppm)PdCl2 (N3), Nafion/Cp(CO)Fe(μ-I)(μ-dppm)PdI2 (N4) and Nafion/Cp(CO)Ru(μ-I)(μ-dppm)PtI2 (N5) on glassy and vitreous carbon electrodes. Cyclic voltammetry and bulk electrolysis experiments were performed to assess the ability of these modified electrodes to electrocatalytically oxidize ethanol. Cyclic voltammograms using the N1–N5 modified glassy carbon electrodes displayed significant catalytic activity compared to oxidation of ethanol catalyzed by 1 in homogeneous solution. Bulk electrolysis of ethanol using electrodes coated with Nafion supported complexes 1–3 resulted in formation of the two- and four-electron oxidation products acetaldehyde and acetic acid, respectively, whilst bulk electrolysis using the complexes 4 and 5 produced only acetaldehyde.