Supported PdPt alloy catalysts: Synthesis, structure characterization and effects of hydrogen absorption

Pd Pt alloy catalysts were prepared by anchoring Pd(II) and Pt(II) organometallic species to the support surface, followed by H2 reduction under mild conditions. This preparation method was exploited for the synthesis of Pd Pt catalysts having different Pd Pt ratios and with total metal loading ~2%; pure Pd and pure Pt catalysts were also obtained. Small Angle X-ray Scattering (SAXS) analysis was used to determine metal dispersion: average metal particle diameter was in the range 20-40 Å both for alloy and single Pd and Pt catalysts. The occurrence of Pd Pt alloy formation was demonstrated by Wide Angle X-ray Scattering (WAXS) and Radial Distribution Function (RDF) analyses. Results both from WAXS and RDF are consistent with each other in ascertaining alloy occurrence, also providing a detailed picture of the behavior of Pt, Pd, and Pd Pt systems in the presence of H2.