Synthesis and catalytic properties of thermally and hydrothermally stable, high-surface-area SiO2-CeO2 mesostructured composite materials and their application for the removal of sulfur compounds from gasoline

Nanostructured SiO2-CeO2 composite materials were prepared by embedding monodispersed, inorganic colloids in ultrafine structured layers of mineral binder using a self-assembly process. Cohesive, highly concentrated CeO2 nanoparticle arrays, characterized by a spacing in the range of a nanoparticle diameter, were synthesized. These materials possess high surface areas and are stable to temperatures up to 800 degreesC by virtue of surface roughness on the nanometer scale and relatively large inorganic layer thickness. Gaseous access to the CeO2 nanoparticle surfaces was obtained through a matching of nanoparticle sizes to the thickness of the structured layers. These SiO2-CeO2 nanostructured materials showed very good catalytic properties as additives for reducing sulfur concentration in gasoline through fluid catalytic cracking. We demonstrate that these thermally stable,, high-surface-area arrays of CeO2 nanoparticles are best suited for the cracking of long-chain, those which commonly present the greatest difficulty, alkylthiophenes and alkylbenzothiophenes. (C) 2004 Elsevier Inc. All rights reserved.