Ghosh, S and Sahu, Ranjan K and Raj, C Retna (2012) Pt-Pd alloy nanoparticle-decorated carbon nanotubes: a durable and methanol tolerant oxygen reduction electrocatalyst. Materials and Corrosion-Werkstoffe Und Korrosion, 23(38) .
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We describe the decoration of multiwalled carbon anotubes (MCNTs) with Pt-Pd alloy nanoelectrocatalysts of three different compositions and their electrocatalytic perfor-mance toward the oxygen reduction reaction (ORR). The decoration of the MCNTs involves polymer-assisted impre-gnation of metal precursors PtCl26- and PdCl42- and the subsequent reduction of the impregnated precursors by a modified polyol route. The composition of the catalyst was controlled by tuning the molar ratio of the precursors during their impregnation. Electron probe microscopic analysis shows that the catalysts have compositions of Pt46Pd54; Pt64Pd36 and Pt28Pd72. The Pt46Pd54 and Pt64Pd36 catalysts have truncated octahedral and icosahedral shapes with a size ranging from 8 to 10 nm. On the other hand, the catalyst of Pt28Pd72 composition has a spherical/ quasispherical shape with a size distribution of 1-2 nm. The XPS measurement confirms the signature of metallic Pt and Pd. The Pt46Pd54 catalyst has a pronounced electro-catalytic activity toward the ORR with a specific and mass activity of 378 mu A cm(Pt-Pd)(-2) and 64 mu A mu g(Pt-Pd)(-1), respectively at 0.8 V. Moreover, the Pt46Pd54 nano-electrocatalyst is highly durable and it retains its initial catalytic activity even after 1000 extensive cycles. Interestingly, this catalyst has a very high tolerance toward methanol and it does not favor the oxi-dation of methanol in the potential window of 0.1-1.4 V. The electrocatalytic activity of the alloy electrocatalyst is compared with commercially available Pt black and MCNT-supported spherical Pt nanoparticles. The catalytic activity of the Pt46Pd54 nanoelectrocatalyst is higher than the other catalysts. The Pt46Pd54 catalyst outper-forms the electrocatalytic activity of all other catalysts.
|Fuel-Cells; Nanostructures; Catalaysts; Surfaces;
|Material Science and Technology
|Dr. A K Sahu
|28 Feb 2013 13:19
|04 Dec 2013 10:23
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