Electrochemical oxidation of formate in dimethylsulfoxide at gold and platinum electrodes

The electrochemical oxidation of formate in dimethylsulfoxide has been studied by chronopotentiometry, controlled-potential coulometry, and cyclic voltammetry at gold electrodes. The oxidation products are carbon dioxide and hydrogen ions, which react with formate ion. Thus, the overall reaction is a one-electron oxidation in which one-half mole of carbon dioxide and one-half mole of formic acid are formed for each mole of formate ion electrolyzed. Cyclic voltammetry indicates that adsorbed free radical intermediates are involved in the oxidation process and that these are coupled between two irreversible charge transfers. Oxidation mechanisms are proposed which are consistent with the data.