(100)-Type behaviour of polycrystalline gold towards O2 reduction

A detailed study of the mechanism of the electroreduction of O2 in alkaline solutions on a stable reconstructed surface of polycrystalline gold is presented. The observed polarization curves are (100)-like. A current maximum corresponding to four electrons per molecule of O2 reacted is observed in the low-overpotential region; evidence is given that a regenerative mechanism is then operative. At potential values below the potential of the maximum, the number of electrons per O2 molecule reacted decreases and becomes smaller than the number observed for the original Au surface. The links between the electrochemistry of the original and reconstructed Au surfaces in the so-called double layer region and the details of O2 reduction on those surfaces are discussed.