High electrochemical activity of Pd/C catalyst with trace amounts of Pd_xH_y

A solvothermal method employing a solvent mixed with tert-butyl alcohol and ethylene glycol was used to prepare activated carbon-supported palladium nanoparticles (Pd/C). The transmission electron microscopy (TEM) and high-resolution transmission electron microscope (HRTEM) results showed that the Pd nanoparticles on this catalyst had a good dispersion, and that their average particle size was small. The X-ray diffraction (XRD) data indicated that the Pd nanoparticles loaded on the activated carbon presented a small particle size and were rich in the Pd (200) crystallographic plane, which provided a high electrochemical activity for the Pd/C catalyst. Furthermore, its activity was greatly improved by the small amount of PdxHy components. By analysing the redox peaks of the electrode loaded with the Pd/C catalyst in a KOH and methanol (ethanol) mixed solution via cyclic voltammetry electrochemical testing, the performances of the prepared catalysts were determined. The results showed that the Pd/C catalyst had an excellent activity and stability, while the Pd/C catalyst synthesised at 190 °C had the best activity and stability. Its current intensity for methanol electrooxidation reached approximately 687.4 mA mg^-1 Pd. In addition, this catalyst had a stronger oxidation ability for ethanol under alkaline conditions, and its oxidation current intensity of ethanol reached approximately 1177.6 mA mg^-1 Pd. The chronoamperometry (CA) results showed that the Pd/C catalyst had an excellent durability, and the electrochemical impedance spectroscopy (EIS) showed that this Pd/C catalyst had an excellent charge transfer efficiency.