Jeyabharathi, C. and Venkateshkumar, P. and Mathiyarasu, J. and Phani, K.L.N. (2010) Carbon-Supported Palladium–Polypyrrole Nanocomposite for Oxygen Reduction and Its Tolerance to Methanol. Journal of the Electrochemical Society, 157 (11). B1740-B1745. ISSN 0013-4651

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Carbon-supported palladium–polypyrrole Pd–PPy/C nanocomposite was synthesized by oxidative polymerization of pyrrole and reduction of palladium(II) precursor salt in the presence of Vulcan XC-72R. The Pd–PPy/C composites were characterized by X-ray diffraction (XRD), Fourier transform IR, X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), and transmission electron microscopy (TEM) techniques. The XRD analysis of Pd–PPy/C shows the formation of the face-centered cubic structure of Pd particles and the mean particle size calculated from TEM was 5.3 2.0 nm. The electrochemical stability of Pd–PPy/C was examined by cyclic voltammetry in an acid solution. The thermal stability and Pd loading in the composite was assessed using TGA. The introduction of Pd in the conducting PPy/C matrix gives better catalytic activity toward oxygen reduction with resistance to methanol oxidation. This was further elucidated by the XPS analysis showing d-band vacancy that is attributed to metal–polymer interaction. From the polarization studies, it is observed that even in the presence of methanol there is no significant cathodic shift in the half-wave potential, revealing that Pd–PPy/C is tolerant to methanol. Rotating ring disk electrode studies show that there is only a negligible quantity of hydrogen peroxide produced in the potential region where its production is expected to be high. This confirms that Pd–PPy/C catalyzes reduction of oxygen directly to water through a four-electron pathway.

Item Type: Article
Subjects: Electrodics and Electrocatalysis
Depositing User: ttbdar CECRI
Date Deposited: 19 Jan 2012 09:12
Last Modified: 19 Jan 2012 09:12

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