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Porous Hollow PtNi/C Electrocatalysts: Carbon Support Considerations To Meet Performance and Stability Requirements

By Tristan Asset, Nathalie Job, yan busby, Alexandre Crisci, Vincent MARTIN, Vaios Stergiopoulos, Alexey Bonnaud, Plamen Atanassov, Raphael Chattot, Laetitia Dubau and Frédéric Maillard

Abstract

International audienceThe influence of the texture, structure, and chemistry of different carbon supports on the morphological properties, oxygen reduction reaction (ORR) activity, and stability of porous hollow PtNi nanoparticles (NPs) was investigated. The carbon nanomaterials included carbon blacks, carbon nanotubes, graphene nanosheets, and carbon xerogel and featured different specific surface areas, degrees of graphitization, and extent of surface functionalization. The external and inner diameters of the supported porous hollow PtNi/C NPs were found to decrease with an increase in the carbon mesopore surface area. Despite these differences, similar morphological properties and electrocatalytic activities for the ORR were reported. The stability of the synthesized electrocatalysts was assessed by simulating electrochemical potential variations occurring at a proton exchange membrane fuel cell (PEMFC) cathode during startup/shutdown events. Identical location transmission electron microscopy (IL-TEM) and electrochemical methods revealed the occurrence of a carbon-specific degradation mechanism: carbon corrosion into CO2 and particle detachment were noticed on carbon xerogels and graphene nanosheets while, on carbon blacks, surface oxidation prevailed (C -> COsurf) and did not result in modified electrical resistance of the catalytic layers, rendering these carbon supports better suited to prepare highly active and stable ORR electrocatalysts

Topics: oxygen reduction reaction, startup/shutdown events, carbon supported porous hollow Pt-based nanoparticles, [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci]
Publisher: 'American Chemical Society (ACS)'
Year: 2018
DOI identifier: 10.1021/acscatal.7b03539
OAI identifier: oai:HAL:hal-02067840v1
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