Potentiodynamic Investigation of Oxygen Reduction Reaction on Polycrystalline Platinum Surface in Acidic Solutions: the Effect of the Polarization Rate on the Kinetic Parameters

摘要

The time of exposure of potentiodynamically polarized platinum electrode to the potentials of oxideformation was considered quantitatively as a factor of kinetics of oxygen reduction reaction (ORR) inacidic, HClO4 and H2SO4 solution. In general, the enhancement of catalytic activity towards ORR wasmeasured upon increasing sweep rate. The results were discussed in terms of the amount of oxideformed on platinum surface, which decreased upon increasing sweep rate. The scope of view was-1 confirmed that the Tafel slope for ORR on oxide-free Pt amounts to 120 mV dec , while various-1 values between 120 and 60 mV dec , reported often in the literature, are governed by the siteblocking/surface reorganization processes.