Glycerol electrooxidation on Pd modified Au surfaces in alkaline media: Effect of the deposition method.

Abstract

The catalytic effect of Pd on gold electrodes for glycerol oxidation is evaluated for Pd-Au surfaces prepared using three different methods: irreversible adsorption of palladium by a simple immersion of a gold electrode in palladium solution, the deposition of palladium on the gold substrate by a step potential from 1 to 0.75 V, and the forced deposition of palladium on the gold electrode with the help of a reducing hydrogen atmosphere. Voltammetry has been used for the electrochemical characterization of the Pd-Au deposits and to determine its reactivity towards glycerol oxidation, whereas FTIR experiments have allowed detecting adsorbed species and products formed during the oxidation reaction. Pd-Au surfaces prepared by irreversible adsorption are the electrodes that show the highest activity for the glycerol complete oxidation to carbonate, whereas Pd-Au surfaces made by the step potential are the catalyst that exhibits the highest rate for the formation and adsorption CO before carbonate production, poisoning the surface and diminishing their electrocatalytic properties. In addition to carbonate, glycerate, glycolate, and formate are detected as oxidation products. The integrated bands of the spectra are used to give quantitative information for comparing the product distribution of the different Pd-Au deposits prepared.