Oxygen Reduction on Platinum in 85% Orthophosphoric Acid

Oxygen reduction on Pt in 85% has been studied using a rotating disk electrode at various temperatures. At a prereduced Pt electrode the Tafel slope is ∼ −0.12 V/decade. Kinetic studies of reduction on Pt at room temperature using rotating ring‐disk technique have shown that in purified 85% the parallel mechanism is operative. The direct reduction to water is the predominant path, and only about 10% of the reduction proceeds via the production of . oxidation and reduction on Pt have also been studied at room temperature using the rotating disk electrode. The oxidation of is one‐half order with respect to while the reduction is first order.