Synthesis at atmospheric pressure and characterization of highly ordered Al, V, and Ti-MCM-41 mesostructured catalysts

Abstract

This work deals with the development of catalytic material type MCM-41, with various heteroatoms, by refluxing the gel mixture at atmospheric pressure under stirring, and the addition of a small amount of promoter oxyanions such as phosphate, reducing the reaction time and increasing the purity, compared with the analogous obtained by hydrothermal procedure, under autogenous pressure without the promoter. The synthesis of highly controlled Al, V and Ti-MCM-41, using colloidal silica and NaAlO 2, isopropyl orthotitanate (IPOT) and VOSO 4·3H 2O as Si, Al, Ti and V sources, were studied. XRD, FTIR, BET, NMR-MAS of 27Al and XAFS measurements, showed that nanostructured catalytic materials prepared, had a highly ordered structure of unidirectional pore arrays, with the heteroatom incorporated as Al 3+, Ti 4+ and V +5,+4 . As expected, in all the cases, an increase in the d spacing (or a 0-values) compared to its siliceous analogue MCM-41 was noted.