Structural analysis of platinum-palladium nanoparticles dispersed on titanium dioxide to evaluate cyclo-olefines reactivity

摘要

Structural and chemical properties were correlated to explain catalytic behavior of Pt-Pd/TiO_2 in a cyclo-olefin reaction. Bimetallic nanoparticles supported on TiO_2 were prepared by wetness impregnation techniques at different concentrations of Pt and Pd≈1 metallic wt%. The physicochemical properties of these metallic nanoparticles supported on TiO_2 were characterized by N_2 physisorption (Brunauer-Emmett-Teller-BET), X-ray diffraction (XRD), and transmission electron microscopy (TEM). The relationship between chemical composition, physicochemical properties and particle size on the cyclo-olefin reaction was then studied. XRD and TEM results show that these nanoparticles are composed of Pt-Pd with FFC structure (a = 0.389-0.391 nm) supported on TiO_2 (anatase-like structure), and the materials present tetragonal structure nanoparticles (a=0.37842, b=0.37842, c=0.95146 nm). Samples with higher contents of platinum and particle sizes of 4.2 nm show the highest catalytic conversion in cyclo-olefins reaction. Finally, structural examinations of Pt_x-Pd_((1-x))/TiO_2 based system was then conducted to study the effects of metals on the nanostructure of the materials.