Cu-Pd/C Electrocatalyst with Low Pd Content toward Methanol Electro-Oxidation

Cu-Pd/C electrocatalyst was synthesized by chemical reduction method from CuSO₄ and K₂PdCl₄ as metallic precursors in the presence of polyvinylpyrrolidone as surfactant and ascorbic acid as reducing agent. The morphology, composition and electrocatalytic properties were investigated by X-Ray Diffraction (XRD), X-Ray Fluorescence (XRF), Transmission Electron Microscopy (TEM), cyclic voltammetry, and chronoamperometry techniques. The electrocatalyst were obtained with homogeneous distribution, average particle size around 5 nm and low percent of Pd (Pd 35%, Cu 65% according to XRF and EDS results) for a catalyst with 70-30 composition. XRD patterns show the typical faced-centered cubic structure, where the (111) plane exhibited a slightly shift. The electrocatalytic activity of Cu-Pd/C was evaluated in terms of methanol electro-oxidation at three concentrations (0.1, 0.3 and 0.5M) in KOH aqueous solution. The results obtained from voltamperometric studies showed that the current density achieved with Cu-Pd/C electrocatalyst is 3 times higher than that reached with commercial Pd (30% from ETEK) and a shift to negative values for electro-oxidation potential.