Characterization of a surface modified carbon cryogel and a carbon supported Pt catalyst

Abstract

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 (S-BET GT 400 m(2) 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 pet-formed in 0.5 mol dm(-3) HCIO4 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 I1/C vs. v(0.5) extrapolation method was found to be 386 F g-l. The hydrogen oxidation reaction at the investigated Pt/C catalyst proceeded as an electrochemically reversible, two-electron direct discharge reaction.