title: Using ordered carbon nanomaterials for shedding light on the mechanism of the cathodic oxygen reduction reaction.
abstract: Insufficient understanding of the mechanism of the cathodic oxygen reduction reaction puts constraints on the improvement of the efficiency of polymer electrolyte fuel cells (PEMFCs). We apply ordered catalytic layers based on vertically aligned carbon nanofilaments and combine experimental rotating ring-disk studies with mathematical modeling for shedding light on the mechanism of the oxygen reduction reaction on Pt nanoparticles. Based on the experimental and simulation evidence we propose a dual path ORR mechanism which comprises a "direct 4e(-)" and a "series 2e(-) + 2e(-)" pathway and explains switching between the two. For the first time we show that below 0.8 V the "direct" path may be discarded and the ORR predominantly occurs via H(2)O(2) mediated pathway, while in the potential interval between ca. 0.8 V and the onset of the ORR the "direct" path is dominating.
authors.affiliation: Laboratoire des Matériaux, Surfaces et Procédés pour la Catalyse, UMR 7515 du CNRS-UdS, Ecole de Chimie, Polymères et Matériaux, Université de Strasbourg, Strasbourg, France.
authors.forename: Pavel S
authors.initials: PS
authors.lastname: Ruvinskiy
authors.forename: Antoine
authors.initials: A
authors.lastname: Bonnefont
authors.forename: Cuong
authors.initials: C
authors.lastname: Pham-Huu
authors.forename: Elena R
authors.initials: ER
authors.lastname: Savinova
mesh_terms: D002244:Carbon / Q000737:chemistry*; D002384:Catalysis; D004563:Electrochemistry / Q000295:instrumentation / Q000379:methods*; D004566:Electrodes; D053768:Metal Nanoparticles / Q000737:chemistry; D008958:Models, Molecular; D008968:Molecular Conformation; D049329:Nanostructures / Q000737:chemistry*; D010084:Oxidation-Reduction; D010100:Oxygen / Q000737:chemistry*; D010984:Platinum / Q000737:chemistry; D012399:Rotation
chemical_list: D010984:Platinum; D002244:Carbon; D010100:Oxygen