OXIDATION-REDUCTION CHEMISTRY OF HYDROGEN-PEROXIDE IN APROTIC AND AQUEOUS-SOLUTIONS

Electrochemical reduction of hydrogen peroxide in pyridine at a platinum electrode yields superoxide ion as the major product. The primary reduction step is H2o2 + e- HO2+1/2H2 which is followed by a disproportionation reaction H02+ H2024ft 02+ H20 + sol-(-OH) oxidation products. In pyridine the approximate value for k2 is 4 X 103 M1 s1, assuming a second-order rate law. In alkaline aqueous solutions H02 is oxidized at a mercury electrode by an overall two-electron process to molecular oxygen. Because H02 is inert at gold and carbon electrodes, the electrochemical oxidation mechanism must involve Hg(I) and Hg(II) intermediate complexes with H02 and or O2. Electrochemicaland ESR studies have been used to determine the products and the reaction stoichiometrics for these processes. © 1979, American Chemical Society. All rights reserved.