Model bulk Mo-V-Te-O catalysts for selective oxidation of propane to acrylic acid

The crystal structures and chemical compositions of the M I and M2 phases proposed as active and selective in propane oxidation to acrylic acid over the bulk mixed Mo-V-Te-O catalysts were investigated by the transmission electron microscopy, coupled with energy dispersive analysis of X-rays. The results revealed that the crystal structure of the M I phase is orthorhombic with space group Pbca, lattice parameters a = 21.25 Angstrom, b = 27.14 Angstrom, c = 4.03 Angstrom and composition Mo0.64V0.32Te0.1O3.05 (Mo/Vsimilar to2), whereas M2 is hexagonal with space group P6mm, lattice parameters a = 7.10 Angstrom. c = 4.05 Angstrom and composition Mo1.79V1.85Te0.1O11.36 (Mo/Vsimilar to1). The M I phase was dominant in the Mo-V-Te-O catalyst. The results obtained indicated that the bulk Mo-V-Te oxides represent a well-defined model catalytic system for the studies of the surface molecular structure-activity/selectivity relationships in propane oxidation to acrylic acid. (C) 2003 Elsevier B.V. All rights reserved.