Performance of Pd Electrocatalyst Supported on a Physical Mixture Indium Tin Oxide-carbon for Glycerol Electro-oxidation in Alkaline Media

Abstract

Palladium electrocatalysts, supported on Vulcan XC 72 carbon and indium tin oxide (ITO) with different ratios, were prepared by borohydride reduction method and analysed for glycerol electro-oxidation application in the presence of KOH solution. Transmission electron microscopy (TEM) and X-ray diffraction (XRD) techniques were used to characterize the particle size and crystal electrocatalyst structures, whereas their catalytic activities regarding the glycerol electro-oxidation were evaluated by cyclic voltammetry (CV), chronoamperometry and tested in a direct alkaline glycerol fuel cell (DGFC) by electrochemical techniques. Micrographs results showed that the ITO presence promotes a large agglomeration of particles. Pd/C-ITO electrocatalysts showed peaks associated with the face-centered cubic (fcc) structure of palladium and several others peaks associated with ITO used as support. Similar performance was found on all Pd/C-ITO electrocatalysts where measurements in CV were compared to Pd/C and Pd/ITO with Pd/C-ITO 50:50 chronoamperometry, presenting a better performance for glycerol electro-oxidation. When using Pd/C-ITO 85:15 electrocatalyst and 1.0mol L-1 glycerol at 90 degrees C, the maximum power density found was 2,1 times higher than that obtained using Pd/C and Pd/CITO electrocatalysts. Therefore, the physical mixture of ITO and carbon, to be used as a support improves the electrocatalytic activity for glycerol oxidation reaction.