Study of protons influence in oxygen reduction in ordered catalytic layers for fuel cell application
Description
Ordered catalytic layers based on vertically aligned carbon nanofilaments with Pt nanoparticles demonstrate high efficiency for oxygen transport and Pt utilization in the catalytic layer. Electrochemical studies combined with mathematical modeling confirm the influence of the proton transport on surface red-ox processes, the kinetics and the mechanism of the O2 reduction (ORR), and on the H2O2 escape. We show that (i) protons are involved in the rate-determining step of the O2 reduction, (ii) for pH = 3, a plateau corresponding to the diffusion-limited current of protons is observed and, (iii) for pH = 3, the mechanism of the ORR involves not only the hydronium ions but also water molecules. The integration of these catalytic layers in high temperature PEMFCs was then studied. The performance is slightly lower than that for conventional layers. An optimization work is required to improve the performance. (author)
Abstract (French)
Les couches catalytiques avec une structure ordonnee a base de nanoparticules de Pt supportees sur des nanofilaments de carbone verticalement alignes ont montre des performances interessantes grace a l'amelioration des proprietes du transport de matiere et a une meilleure utilisation du Pt. Des etudes electrochimiques combinees a une modelisation mathematique ont mis en evidence l'influence du transport de protons sur les processus d'oxydo-reduction, la cinetique et le mecanisme de reduction de l'O2 (ORR), et sur H2O2 qui s'echappe des couches pendant l'ORR. Nous avons montre que (i) les protons sont impliques dans l'etape limitante de la reaction, (ii) pour un pH = 3, un plateau de courant limite par la diffusion des protons est observe et, (iii) pour un pH = 3, le mecanisme de l'ORR implique non seulement les ions hydroniums mais aussi les molecules d'eau. L'integration de ces couches catalytiques dans des PEMFCs haute temperature a ensuite ete etudiee. Les performances obtenues sont legerement plus basses que celles des couches conventionnelles. Un travail d'optimisation reste donc a accomplir pour ameliorer les performances. (auteur)
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Additional details
Additional titles
- Original title (French)
- Etude de l'influence des protons sur la reduction de l'oxygene dans des couches catalytiques ordonnees en vue d'une application en pile a combustible
Publishing Information
- Imprint Pagination
- 297 p.
- Report number
- FRNC-TH--14633
INIS
- Country of Publication
- France
- Country of Input or Organization
- France
- INIS RN
- 54076902
- Subject category
- S36: MATERIALS SCIENCE; S37: INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY;
- Resource subtype / Literary indicator
- Thesis
- Descriptors DEI
- CARBON MONOXIDE; CARBON NANOTUBES; CHEMICAL REACTION KINETICS; CHEMICAL VAPOR DEPOSITION; ELECTRIC CONDUCTIVITY; ELECTROCATALYSTS; ELECTROLYTES; HYDROGEN PEROXIDE; NANOPARTICLES; OXYGEN; PH VALUE; PLATINUM; POLARIZATION; PROTON EXCHANGE MEMBRANE FUEL CELLS; PROTON TRANSPORT; REDOX PROCESS; REDUCTION; STRIPPING; TEMPERATURE DEPENDENCE
- Descriptors DEC
- CARBON; CARBON COMPOUNDS; CARBON OXIDES; CATALYSTS; CHALCOGENIDES; CHARGED-PARTICLE TRANSPORT; CHEMICAL COATING; CHEMICAL REACTIONS; DEPOSITION; DIRECT ENERGY CONVERTERS; DIRECT REACTIONS; ELECTRICAL PROPERTIES; ELECTROCHEMICAL CELLS; ELEMENTS; FUEL CELLS; HYDROGEN COMPOUNDS; KINETICS; METALS; NANOSTRUCTURES; NANOTUBES; NONMETALS; NUCLEAR REACTIONS; OXIDES; OXYGEN COMPOUNDS; PARTICLES; PEROXIDES; PHYSICAL PROPERTIES; PLATINUM METALS; RADIATION TRANSPORT; REACTION KINETICS; REPROCESSING; SEPARATION PROCESSES; SOLID ELECTROLYTE FUEL CELLS; SURFACE COATING; TRANSFER REACTIONS; TRANSITION ELEMENTS
Optional Information
- Notes
- 93 refs.; Available from the INIS Liaison Officer for France, see the INIS website for current contact and E-mail addresses