The Effects of Pb, Cd, Tl, Cu, Ag and Bi Adatoms on Glyoxalate Oxidation Reactions on Au Electrodes in Alkaline Medium

Glyoxalate oxidation has been investigated in alkaline medium both on bare Au and adatom modified Au electrodes. The kinetic parameters measured on bare Au electrodes as well as other experimental data lead to the formulation of a reaction mechanism for the electrooxidation on the bare Au surface to the Oxalate anion as the final product. The addition of small amounts of Pb, Cd, TI, Cu and Ag results in a substantial catalytic effect on the oxidation on gold. The oxidation potential shifts around 300 mV in negative direction. Bi and, at higher concentrations, also Cd, give rise to an inhibition of glyoxalate oxidation. The inhibiting effect can be associated with the formation of a dense underpotential deposited layer of adatoms.

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