Oxygen and Hydrogen Peroxide Reduction on Polycrystalline Platinum in Acid Electrolytes: Effects of Bromide Adsorption

摘要: Changes in the electrocatalytic activity of Pt for oxygen and hydrogen peroxide reduction reactions (ORR HPRR, respectively) an aqueous acidic electrolyte induced by adsorption bromide, as a model impurity, have been investigated using chronoamperometric techniques under forced convection. Experiments were carried out polycrystalline Pt|Pt rotating ring-disk electrode O2-saturated 0.1 M HClO4 containing 10 μM KBr (800 ppb). Potential steps applied to disk from Eo, at which Br– is fully desorbed, more positive values, Estep, undergoes adsorption. During this period, currents both disk, idisk, ring, iring, monitored, with ring polarized potential H2O2(aq) oxidation proceeds diffusion-limited conditions. The results obtained, assuming ORR does not interfere adsorption, made it possible correlate idisk iring coverage adsorbed Br–, θBr–, Estep. As evidenced da...