Journal of the Serbian Chemical Society 2007 Volume 72, Issue 8-9, Pages: 773-785
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Characterization of a surface modified carbon cryogel and a carbon supported pt catalyst
Babić Biljana M., Kaluđerović Branka V., Vračar Ljiljana M., Radmilović Velimir, Krstajić Nedeljko V.
A carbon cryogel, synthesized by carbonization of a resorcinol/formaldehyde cryogel and oxidized in nitric acid, was used as catalyst support for Pt nanoparticles. The Pt/C catalyst was prepared by a modified polyol synthesis method in an ethylene glycol (EG) solution. Characterization by nitrogen adsorption showed that the carbon cryogel support and the Pt/C catalyst were mesoporous materials with high specific surface areas (Sbet>400 m2 g-1) and large mesoporous volumes. X-Ray diffraction of the catalyst demonstrated the successful reduction of the Pt precursor to metallic form. TEM Images of the Pt/C catalyst and Pt particle size distribution showed that the mean Pt particle size was about 3.3 nm. Cyclic voltammetry (CV) experiments at various scan rates (from 2 to 200 mV s-1) were performed in 0.5 mol dm-3 HClO4 solution. The large capacitance of the oxidized carbon cryogel electrode, which arises from a combination of the double-layer capacitance and pseudocapacitance, associated with the participation of surface redox-type reactions was demonstrated. For the oxidized carbon cryogel, the total specific capacitance determined by 1/C vs. v0.5 extrapolation method was found to be 386 F g-1. The hydrogen oxidation reaction at the investigated Pt/C catalyst proceeded as an electrochemically reversible, two-electron direct discharge reaction. .
Keywords: carbon cryogel, platinum catalyst, hydrogen oxidation, fuel cell