EXAFS characterization of supported PtRu/MgO prepared from a molecular precursor and organometallic mixture

ABSTRACT Supported bimetallic PtRu/MgO catalysts were prepared by adsorption of MgO with Pt3Ru6(CO) 21 (μ 3 -H)(μ-H) 3 in CH 2 Cl 2 cluster or a mixture of Pt(acac) 2 and Ru(acac) 3 in toluene (acac = acetylacetonate). High metal dispersion was obtained in the catalysts after treated in He or H 2 at 300°C to remove ligands. Changes of the cluster before and after treatment, monitored by infrared (IR) spectroscopy indicated that it was not intact during adsorption on MgO. However, it was still metallic carbonyl species and was not extractable from support by CH 2 Cl 2 solvent. After ligand removal, PtRu/MgO catalysts from both precursors were characterized by extended X-ray absorption fine structure (EXAFS) spectroscopy. Only the catalyst prepared from the cluster precursor contained Pt-Ru bonds with lower Pt-Ru contributions than the original precursor due to strong metal-support interactions. Although activity for ethylene hydrogenation at low temperatures was observed on the both catalysts, it was slightly lower in the catalyst prepared from the cluster precursor.