Abstract:
Pt/C and PtRu/C catalysts with different ratios of Pt to Ru were synthesized, using ethylene glycol as both the dispersant and reducing agent at 1-2 MPa by microwaveassisted method. The catalysts were characterized by XRD, TEM and XPS. The mean particle sizes of the Pt/C and PtRu/C catalysts were 1.9-2.0 nm. Pt and Ru existed as Pt(0), Pt(Ⅱ), Pt(Ⅳ), Ru(0) and Ru(Ⅳ) for Pt-Ru/C catalysts, respectively. The facecentered cubic structure of the active mental particles would be changed upon the addition of Ru gradually. Then polytetrafluoroethylene and carbon supported Pt and Pt-Ru catalysts were supported on foamed nickel to obtain hydrophobic catalysts. The catalytic activity was increased for liquid phase catalytic exchange (LPCE) when uniform Pt based hydrophobic catalysts was mixed into appropriate Ru. Hydrogen isotope exchange reaction occurs between hydration layer (H2O)nH+(ads)(n≥2) and D atoms due to intact water molecules being on Pt surface for LPCE. Water molecules have a tendency to dissociate to OH (ads) and H (ads) on metal Ru surface, and there is the other reaction path for Pt-Ru binary catalysts, which is probably the main reason of the increase of the catalytic activity of the hydrophobic Pt-Ru catalyst.