Glycerol oxidation on Pd nanocatalysts obtained on PEDOT-coated graphite supports

Abstract

Glycerol oxidation is studied at Pd nanoparticles (NPs) obtained by electroless metal deposition on PEDOT-coated graphite electrodes. Pre-reduced PEDOT coatings with different polymerization charges and different doping ions (polystyrenesulfonate, PSS or dodecyl sulfate, SDS) are used to drive the electroless deposition of Pd NPs. Pd nanocatalysts with metal loadings in the order of 15–30 μgcm−2 and high electroactive surface area (EASA) are obtained. Oxidation of glycerol is studied in dependence of the type of doping (PSS or SDS) and polymerization charge. It is found that at constant Pd loading PEDOT/PSS-supported catalysts have a three times higher glycerol peak oxidation currents. The mass activity (MA) diminishes with increasing Pd loading on both types of PEDOT but for different reasons. Impeded access of glycerol to NPs deposited deeply in the polymer structure is suggested for the porous and hydrophilic structure of PEDOT/PSS. Aggregation of NPs and therefore smaller EASA due to the upper surface confined metal deposition process are operative at PEDOT/SDS coatings. These are also the reasons for the low MA values observed on this type of PEDOT support. MA values at PEDOT/PSS-coated graphite are found to range between 1100 and 1200 mAmg−1 and are between the best values obtained on Pd-supported catalysts.