Oxygen reduction mechanisms at p-InP and p-GaAs electrodes in liquid ammonia in neutral buffered medium and acidic media

The use of buffered neutral liquid ammonia medium for the first time provid ed evidence for a current doubling effect on p-InP during oxygen photoreduc tion. Unlike results in aqueous medium, a common mechanism of O-2 reduction was observed at p-InP and p-GaAs electrodes. When protons were added to th e solution, two different oxygen reduction mechanisms occurred at these ele ctrodes. This study emphasizes the important results of the hydrogenated p- InP surface and revealed that liquid ammonia (at 223 K) was perfectly appro priate to understand the mechanism of O-2 reduction at InP electrodes. (C) 1999 Elsevier Science S.A. All rights reserved.