Electro-Oxidation of Glyoxylic Acid on Pt Polycrystailine Electrodes in Acidic Solutions

The electrocatalytic oxidation of glyoxylic acid in acid medium on platinum electrodes has been investigated. The oxidation mechanism proposed excludes any dissociative adsorption of the organic molecules. This fact is explained as the consequence of the stabilization ofthe C~H bond in the aldehyde group induced by the deactivating and polarizing effects exerted by the carboxylic group. Ideas for the explanation ofoxidation currents produced by aldehydes, alcohols, and other organic compounds in the potential range corresponding to the double-layer charging are given in the context of the discussion of the glyoxylic acid electro-oxidation mechanism. The oxidation mechanism ofmany organic substances on Pt electrodes, for instance formaldehyde, formic acid, or methanol seems to take place through a dissociative ad-sorption step. 1- ~ Also, the shapes of the voltammograms recorded in any of the above-cited cases as well as in other examples are similar to each other, presenting high oxida-tion current maxima in the potential range corresponding to the double-layer region on Pt electrodes