Nanostructured Heterogeneous Catalysts: Well Defined Platinum Nanoparticles Supported on Alumina. Preparation, Characterization and Application to the Selective Hydrogenation of Buta-1,3-diene

Abstract

Platinum nanoparticles with specific morphologies were prepared in aqueous solution. Key parameters, such as cationic surfactant (cetyltrimethylammonium bromide CTAB) and platinum precursor (H2PtCl6) ratio, temperature, atmosphere (argon or hydrogen), were required to control the formation of nanostructured platinum particles, with well defined morphologies, and even to control their morphology. Platinum nanoparticles with mainly cubic morphologies, with a mix of morphologies (rods, cubes, tetrahedra) or with mainly polyhedric morphologies, were thus obtained depending on CTAB/Pt ratio, atmosphere and temperature. A mechanism of formation of theses platinum nanoparticles was proposed using a time resolved transmission electron microscopy study. After deposition onto Al2O3, the well crystallized nanostructured platinum particles were evaluated in the selective hydrogenation of buta-1,3-diene. Catalysts prepared with platinum nanoparticles exposing mainly the (111) crystallographic plane (polyhedric morphologies) were the most selective for the selective hydrogenation of buta-1,3-diene into butenes with a drastic decreasing of further hydrogenation into n-butane. Copyright © 2009, Institut francais du petrole.