Síntesis y caracterización de catalizadores de Pd soportados en carbón para celdas de combustible de baja temperatura

JORGE J. ACOSTA; PABLO C. FAVILLA; ALICIA E. ARES Y CARLOS E. SCHVEZOV; JUAN R. COLLET-LACOSTE

Santa Fe

Congreso; Congreso Internacional De Metalurgia y Materiales. Sam ? Conamet / Iberomat / Materia 2014; 2014

sam - Asociación Argentina de Materiales

In the present work we show the results obtained in Pd catalysts supported on Vulcan XC-72R synthesized by the modified polyol (ethylene glycol) method. The characterization of these was conducted by means of: TEM, STEM, XRD, Cyclic voltammetry (CV) and stripping of CO. The synthesis was carried out at different initial pH´s solutions for a constant initial concentration of the precursor of 2 mM. In addition, other synthesis was carried out by varying the initial concentration of precursor remaining constant at 12 the initial pH of the solution. From the data obtained by TEM for each catalyst we measured the diameters of more than 300 particles in order to calculate its average diameter and standard deviation. It was observed a linear relationship between the average volume of nanoparticles and the square root of the initial concentration of precursor. In addition, a variation of the mean diameters with the initial pH of the solution was observed and this correlated with the concentration of glycolate ions that occurs during the reduction of the precursor through oxidation of ethylene glycol. These results are in agreement with the measures of specific area obtained by VC and stripping of CO. It also shows the correlation between the standard deviation of the diameters and the average volume of the nanoparticles, which was justified through the theory of fluctuations in concentration.