Textural, acidic and catalytic properties of niobium phosphate and of niobium oxide

Niobic acid and niobium phosphate as highly acidic viable catalysts in aqueous medium: Fructose dehydration reaction

“…The Brønsted acidity of niobic acid is very high (H 0 À5.6), niobium phosphate has also acid properties (H 0 À8.2) with a higher ratio of Lewis/ Brønsted acid sites. The textural, acidic, and catalytic properties of NBP are superior to those of NBO, with the advantage that these properties are preserved at higher temperatures [6][7][8][9][10].…”

Niobium phosphates as an intermediate temperature proton conducting electrolyte for fuel cells

“…16 Most importantly, the surface acidity of niobium phosphates can be preserved in the above mentioned temperature range. [21][22][23] Niobium oxide phosphate (NbOPO 4 ), for example, is known to have a layered structure, in which a distorted NbO 6 octahedron is connected to PO 4 tetrahedra via shared corners. 24 This structure allows for intercalation of guest molecules such as alcohols, amines, water and acids e.g.…”

Isomerization of 3,3-dimethyl-1-butene over aluminum and chromium orthophosphates

“…Besides, in every case the 23DMB2/23DMB 1 ratio increases with the conversion, becoming equal to the thermodynamic equilibrium ratio for conversions greater than 10-15 mol%, as it was described on other catalysts [12].…”

“…The 33DMB 1 skeletal isomerization has been studied on various metal oxides [1][2][3][4][5][6][7][8][9][10] and phosphates [11,12] and thus, it becomes a model reaction for the Bronsted acidity [13].…”