Sb, V, Nb containing catalysts in low temperature oxidation of methanol – The effect of preparation method on activity and selectivity
2011
Golinska-Mazwa, Hanna | Decyk, Piotr | Ziolek, Maria
This study deals with the influence of preparation method of SbVOₓ binary oxides and modification with niobium on the catalytic properties in the oxidation of methanol. The samples were prepared in the presence of a template by two different procedures with and without the template (Pluronic 123). The template-assisted synthesis leads to higher surface area and pore volume as well as smaller size particles of different shapes than those in the materials synthesised without the template. The rutile SbVO₄ phase dominates in all the catalysts studied. The preparation procedure determines the formation of the additives (V₂O₅ or Sb₂O₄) and the concentration of oxovanadium species on the catalyst surface. The presence of a small amount of Sb₂O₄ acting as an electronic promoter in the oxidation of methanol is found when template-assisted synthesis is applied. Such a synthesis involves the formation of reducible oxovanadium species containing nucleophilic oxygen, playing an important role in the oxidation of methanol. Niobium loaded changes the selectivity towards DMM production. It has been found that by using different procedures of synthesis of binary SbVOₓ oxides and modification with niobium species, it is possible to obtain catalysts useful for the selective production of desired products (FA or MF or DMM) of methanol oxidation.
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