The Mechanism of Oxygen Evolution on Nickel, Platinum, and Other Metals and Alloys

The oxygen evolution reaction in has been studied by low speed linear sweep voltammetry of several metals including: Ni, Pt, Co, Fe, , , and . The Tafel slope for all these metals at early stages of the oxygen evolution wave was found to be about 46 mV/dec. For nickel and its alloys, dual Tafel regions were observed wherein, at even lower current densities, the slope was 34 mV/dec. A recently proposed theory for interpreting Tafel slopes is applied to these results, and a mechanism involving a three‐step formation of adsorbed hydrogen peroxide is given. The exchange current density for several of these steps is evaluated, and the results are found to be consistent with the properties of the metals.