Interaction of hydrogen peroxide with a Pt(111) electrode

Hydrogen peroxide is recognized as one of the most probable intermediate species during oxygen reduction reaction (ORR) on various metals. In this work, H2O2 reduction and oxidation on Pt(111) have been studied in a non-adsorbing electrolyte by cyclic voltammetry and online electrochemical mass spectrometry. H2O2 is oxidized and reduced into two different, but interrelated electron transfer processes. As the potential increases, the reduction of H2O2 switches rapidly to its oxidation at -E>0.9 V. The whole process exhibits a marked hysteresis in the mixed charge transfer-diffusion controlled potential region, together with current overshoots at E>0.85 V and E<0.27 V in quiescent solutions. At high potentials, Pt(111) oxides and O-2 evolution explain the current-potential characteristics, while at low potentials, hydrogen adsorption is at the origin of the current response. (C) 2012 Elsevier B.V. All rights reserved.