Synthesis and Evaluation of Pd/C and PdAg/C Catalysts Prepared by Polyol Process and Reverse Micelles Methods for Ethanol Oxidation Reaction

Carbon-supported Pd and PdAg nanoparticles are synthesized by polyol (P) and reverse micelles (RM) methods to perform a comparative study as catalysts for ethanol electro-oxidation in alkaline media. The aim of present work is to synthesize Pd/C and PdAg/C catalysts by polyol and reverse micelles methods in order to reduce the cost of the electrode anode material and increasing the catalytic activity towards EOR. PdAg/C is evaluated at different ethanol concentrations in alkaline medium. The catalysts were structurally characterized by X-ray Diffraction (XRD), Transmission Electron Microscopy (TEM) and Thermo-Gravimetric (TG) analysis. The electrocatalytic performance was studied by Cyclic Voltammetry in absence and presence of ethanol, Chronoamperometry and Electrochemical Impedance Spectroscopy (EIS). Electrochemical measurements showed that the catalysts obtained by reverse micelles presented excellent dispersion and small crystal size, resulting in materials with high electro-active area. However, the PdAg/C catalysts prepared by polyol process presented better catalytic activity and stability during the electro-oxidation reaction (EOR). Besides the excellent dispersion and low agglomeration promoted by using the polyol method, the catalytic enhancement can be also associated to the synergic effect between Pd and Ag elements.