Sol−Gel Method for Preparing Vanadium−Antimony Oxide Catalysts

Abstract

Vanadium-antimony oxide selective oxidation catalysts are prepared using a novel peroxide-based sol-gel synthesis procedure. The catalysts are prepared by reaction of soluble peroxovanadium complexes with antimony trioxide under refluxing conditions. The procedure produces a stable colloidal sol of microcrystalline rutile vanadium antimonate having an average particle size of 6.7 nm. Drying the sol gives a gel consisting of pure rutile vanadium antimonate having the vanadium/antimony ratio of about 1/1, consistent with the stoichiometry of the well-characterized crystalline phase V 8/9 Sb 8/9 0 2/9 O 4 . The driving force for the formation of this phase is the redox reaction between a V 5+ peroxo complex and Sb 3+ oxide to form the V 4+ ,Sb 5+ -containing vanadium antimonate. The peroxide-based solgel preparation procedure allows formation of vanadium antimonate under milder conditions than previous synthesis methods that rely on heating of mixtures of vanadium and antimony oxides.

Effect of synthesis method on stabilized nano-scaled Sb–V–O catalysts for the ammoxidation of propane to acrylonitrile

“…Others studies try to keep vanadium as V 4+ in oxalic acid and then add antimonic acid to this solution [25] or prepare catalysts with a solution of VCl 3 and SbCl 5 on HCl [12,26]. A sol-gel method has also been reported for this kind of catalysts [27].…”

Niobia-supported Sb–V–O catalysts for propane ammoxidation: effect of catalyst composition on the selectivity to acrylonitrile

“…10,17,18 The performance of this kind of catalysts is strongly dependent on the characteristics of the calcination environment, which determines their structures. 1,19,20 The most efficient catalysts for propane ammoxidation possess V, which combines with Sb or Nb oxides. Catalysts possessing V, Sb and Nb oxides also exhibit a good performance; however, it appears that the Sb-Nb interaction is stronger than that leading to Sb-V-O or Nb-V-O mixed oxides.…”

Vanadia Gel Synthesis via Peroxovanadate Precursors. 1. In Situ Laser Raman and 51V NMR Characterization of the Gelation Process

“…Brazdil et al have described the preparation of vanadium-antimony oxide catalysts for the selective oxidation or ammoxidation of several hydrocarbons. 9,10 The advantages of these materials were increased catalytic activity, milder preparation conditions, homogeneous distribution of the metal constituents, increased surface area and porosity, and resistance to attrition. 11 These improvements were attributed to the microcrystalline nature of the catalyst resulting from thermal treatment of the sol-gel material.…”