Insertion of vanadium or molybdenum as oxides in LaNaY zeolite: comparison with NaY

Abstract

When mixtures of NaY or LaNaY zeolites with V₂O₅ or MoO₃ are calcined in air at atmospheric pressure within given temperature and composition ranges, the oxides can migrate into the pores of the zeolite lattice. The extent of insertion is higher for LaNaY than for NaY; this is attributable to the space in the supercages left vacant by the migration of the La³⁺ ions into the sodalite cages or hexagonal prisms. Beyond certain temperature and oxide concentrations the NaY or LaNaY lattice is destroyed and new crystalline phases are formed. These solid-state interactions and reactions have been followed by X-ray diffraction (XRD) and by ²⁷Al and ²⁹Si magic-angle spinning (MAS) NMR.