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Electrochemical Performance of Dispersed Pt-M (M =V, Cr and Co) Nanoparticles for the Oxygen Reduction Electrocatalysis

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Author(s): Giz , M. Janete | Lima H. B. , Fabio | Ticianelli , Edson A.

Journal: Revista de la Sociedad Química de México
ISSN 0583-7693

Volume: 49;
Issue: 2;
Start page: 90;
Date: 2005;
Original page

Keywords: oxygen reduction | platinum alloys | X-ray absorption

ABSTRACT
The kinetics of the oxygen reduction reaction (ORR) was studied in KOH electrolyte on ultra thin layer electrodes formed by Pt-V, Pt-Cr and Pt-Co electrocatalysts dispersed on a carbon powder (Pt-M/C). The electronic and structural features of the materials were studied by in situ XANES (Xray Absorption Near Edge Structure) and EXAFS (Extended X-ray Absorption Fine Structure). Cyclic voltammograms and steady state polarization curves for the ORR were obtained using the rotating ring/disk electrode technique. The XANES results for the composites in the oxidized state have shown an increase of the occupancy of the Pt 5d band while the EXAFS analyses showed some reduction of the Pt-Pt interatomic distance in the different metal alloys compared to Pt/C. The electrochemical measurements indicated that the 4-electrons mechanism is mainly followed for the ORR in these platinum alloys. The highest electrocatalytic activity was shown by the Pt-V/C alloy, after treated at 850 oC under hydrogen atmosphere.
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Tango Rapperswil
Tango Rapperswil