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Characterisation of variations in vanadium phosphate catalyst microstructure with preparation route

Journal Article · · Journal of Catalysis
; ;  [1]
  1. Univ. of Liverpool (United Kingdom); and others
Three vanadium phosphate catalysts prepared by different methods are compared and contrasted for the selective oxidation of n-butane to maleic anhydride. VOHPO{sub 4} 0.5H{sub 2}O catalyst precursors were prepared via three distinct routes: (a) using aqueous HCl as reductant for V{sub 2}O{sub 5}, (b) using isobutanol as solvent and reductant for V{sub 2}O{sub 5}, (b) using isobutanol as a reducing agent for VOPO{sub 4}{center_dot}2H{sub 2}O. The precursors were transformed under identical conditions (385{degrees}C, 1.5% butane in air, 1000 h{sup -1}, 75 h) to three activated catalysts. The morphology of the precursors and the final catalysts have been assessed using a combination of X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and {sup 31}P NMR spin-echo mapping. Even though they exhibited very similar specific activities for maleic anhydride production, the three activated vanadium phosphate catalysts were found to have widely varying morphologies. The implications of this observation are discussed and a few suggestions are made as to the possible nature of the active site in this catalyst system. The material derived from the reduction of VOPO{sub 4}{center_dot}2H{sub 2}O exhibited the highest catalyst activity by virtue of its optimised (VO){sub 2}P{sub 2}O{sub 7} morphology and high surface area. 37 refs., 11 figs., 2 tabs.
OSTI ID:
508439
Journal Information:
Journal of Catalysis, Journal Name: Journal of Catalysis Journal Issue: 1 Vol. 162; ISSN 0021-9517; ISSN JCTLA5
Country of Publication:
United States
Language:
English