New rutile Ga/V/Nb/Sb mixed oxides as catalysts for propane ammoxidation to acrylonitrile

Here we report on the chemical–physical characteristics and reactivity in propane ammoxidation to acrylonitrile of a new class of rutile-type, GaSbO4-based multicomponent oxides. The GaSbO4 rutile was much less active than the conventional VSbO4-based rutile systems, but showed a good selectivity to acrylonitrile. The incorporation of V in GaSbO4 allowed for an improvement in catalytic activity, but with decreased maximum selectivity to acrylonitrile. However, the further incorporation of Nb (thereby developing a Ga/V/Nb/Sb mixed oxide) led to a mixed oxide that presented an enhanced catalytic behavior, combining both high activity and high selectivity to acrylonitrile. The Nb presence also greatly improved the stability of the catalytic system, hindering the crystallization phenomena observed with rutile Ga/V/Sb/O systems.

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► Rutile GaSbO4 systems are the basis for the preparation of multicomponent oxides.
► Rutile Ga/V/Sb/Nb mixed oxides are active in propane ammoxidation to acrylonitrile.
► The presence of V in Ga/V/Sb/Nb mixed oxides increases catalyst activity.
► The presence of Nb in Ga/V/Sb/Nb mixed oxides increases selectivity to acrylonitrile.
► An additional role of Nb is to stabilize the morphology of the microcrystalline rutile oxide.