A reviewed vision of the oxygen reduction reaction mechanism on Pt-based catalysts

In this work, a short revised analysis regarding the ORR mechanism at Pt-based surfaces has been performed and some common kinetic criteria have been reexamined in light of recent experimental results. In this sense, the production of H2O2 under high mass transport conditions and the lack of reduction currents at potentials higher than the experimental reaction onset, EonsetORR, have been analyzed, considering the existence of a soluble intermediate species and an outer sphere reaction inside the ORR mechanism, besides the possible occurrence of a zero current cycle at EonsetORR. Finally, the implications of these findings in the stability and durability of Pt-based catalysts have been also discussed.