Oxidative dehydrogenation of ethylbenzene over vanadia-alumina catalysts in the presence of nitrous oxide: structure-activity relationship

Glycerol Valorization: Dehydration to Acrolein Over Silica-Supported Niobia Catalysts

“…This indicates a high dispersion of niobia and stronger interaction between the supported niobia species and silica. Such interactions are frequently observed for supported metal oxides [27]. Table 1 gives the textural properties derived from nitrogen physisorption isotherms.…”

The advantage of ceria loading over V2O5/Al2O3 catalyst for vapor phase oxidative dehydrogenation of ethylbenzene to styrene using CO2 as a soft oxidant

“…The shift in T max value with increasing vanadia loading results from the reduction of monomeric, dimeric or low oligomeric surface vanadia species. The shift in reduction peaks with increase in vanadium content may be ascribed to the progressive increase in polymeric vanadium species [22]. In our present study, the catalyst VA showed a high intense signal at around 803 K and another small intense shoulder peak at around 943 K. The low-temperature peak might be attributed to the reduction of dispersed surface vanadium species mostly due to the presence of monomeric phase (tetragonal phase) of the vanadia species, while the high temperature peak should be ascribed to the reduction of bulk V 2 O 5 -like V 5?…”

“…Among several reported supports, alumina has major contribution because of their surface area, better redox properties, and high thermal stability. The molecular structure and reactivity of Vanadia supported alumina have been keenly investigated for few decades over dehydrogenation of EB [22][23][24][25]. Also, the CeO 2 -based mixed oxides are effective catalysts for the oxidation of different hydrocarbons and for the removal of total organic carbon from polluted waters from different sources [26,27].…”

Síntese, caracterização e avaliação das propriedades catalíticas de VOx/Ta2O5-Al2O3 para a reação de decomposição do isopropanol

“…A histerese do tipo 3 está associada à formação de poros mais largos (SING et al, 1985). A única exceção é o suporte 15TaAl que apresentou histerese do tipo 4, 0,3 ≤ P/P 0 ≤ 0,9, que está associada a poros mais estreitos em fendas (FIGUEIREDO; RIBEIRO, 1987).…”

“…Este resultado pode ser associado a uma boa dispersão das partículas de óxido de vanádio superficiais. Shiju et al, (2005), para catalisadores V 2 O 5 -Al 2 O 3 com concentração de até 10% em peso de vanádio, também observaram apenas picos referentes a γ-Al 2 O 3 . Klose et al, (2007), para catalisadores com densidade do vanádio de 4,9 átomos/nm², obteve difratogramas sem reflexão aparentes indicando a presença apenas de vanadato, o qual não apresenta aspecto cristalino ao DRX.…”