Provided in this disclosure are catalyst compositions. The catalyst compositions include an oxidative dehydrogenation catalyst that includes a mixed metal oxide having the empirical formula:

Mo.sub.1.0V.sub.0.12-0.49Te.sub.0.05-0.17Nb.sub.0.10-0.20Al.sub.cO.sub.d

wherein c is from 0 to 2.0 and d is a number to satisfy the valence of the oxide. The compositions are at least 40 wt. % amorphous as measured by XRD. The disclosure also provides methods of making the compositions.

This document relates to oxidative dehydrogenation catalysts that include molybdenum, vanadium, and oxygen.

The invention relates to a process of the oxidative dehydrogenation of an alkane containing 2 to 6 carbon atoms and/or the oxidation of an alkene containing 2 to 6 carbon atoms, wherein oxygen, water and the alkane and/or alkene are fed to a reactor and are contacted with a mixed metal oxide catalyst containing molybdenum, vanadium, niobium and optionally tellurium in the reactor, and wherein the molar ratio of water as fed to the reactor to oxygen as fed to the reactor is smaller than 1:1.

A catalyst, useful for oxidative dehydrogenation of ethane, comprising molybdenum, vanadium, tellurium, tantalum, and oxygen, prepared using a stage hydrothermal synthesis procedure, is provided. The catalyst comprises from 30 to 50 wt. % amorphous content and may be combined with a support/carrier material to form a catalyst material. The described catalysts and catalyst materials demonstrate high selectivity for ethylene at higher temperatures, show little to no decline in conversion and selectivity over time, and do not appear to be sensitive to low residual oxygen concentrations.

Oxidative dehydrogenation catalysts comprising MoVNbTeO having improved consistency of composition and a 25% conversion of ethylene at less than 420 C. and a selectivity to ethylene above 95% are prepared by treating the catalyst precursor with H.sub.2O.sub.2 in an amount equivalent to 0.30-2.8 mL H.sub.2O.sub.2 of a 30% solution per gram of catalyst precursor prior to calcining and treating the resulting catalyst with the equivalent amount of peroxide after calcining.

A method for preparing a mixed-metal oxide catalyst comprising molybdenum, vanadium, at least one of niobium or tantalum, and at least one of tellurium or antimony and useful for the oxidative dehydrogenation of ethane to ethylene, the method comprising preparing a catalyst precursor, pressing the precursor into a dense pellet using a pressure of greater than about 5,000 psi, and annealing the pellet to form the mixed-metal oxide catalyst.

The invention relates to a process of the oxidative dehydrogenation of an alkane containing 2 to 6 carbon atoms and/or the oxidation of an alkene containing 2 to 6 carbon atoms, comprising contacting a first gas stream comprising oxygen and the alkane containing 2 to 6 carbon atoms and/or the alkene containing 2 to 6 carbon atoms with a mixed metal oxide catalyst containing molybdenum, vanadium, niobium and optionally tellurium; followed by contacting a second gas stream comprising methane, an inert gas or oxygen or any combination of two or more of these with the catalyst, wherein the second gas stream comprises 0 to 25 vol. % of the alkane containing 2 to 6 carbon atoms and/or alkene containing 2 to 6 carbon atoms.

The invention relates to a method for producing a mixed oxide material containing the elements molybdenum, vanadium, niobium and tellurium, comprising the following steps: a) producing a mixture from starting compounds containing molybdenum, vanadium, niobium and a tellurium-containing starting compound, present in the tellurium in the +4 oxidation state, b) hydrothermal treatment of the mixture from starting compounds at a temperature of between 100 C. to 300 C., in order to obtain a product suspension, c) separating off and drying the solid material from the product suspension obtained in step b), d) activating the solid material in inert gas in order to obtain the mixed oxide material. The invention is characterized in that the tellurium-containing starting compound has a particle size D.sub.90 of less than 100 m.

A catalyst material includes molybdenum (Mo): vanadium (V). the molar ratio of Mo:V being between 1:0.12 and 1:0.49; tellurium (Te), the molar ratio of Mo:Te being between 1:0.01 and 1:0.30; niobium (Nb), the molar ratio of Mo:Nb being between 1:0.01 and 1:0.30; and beryllium (Be), the molar ratio of Mo:Be being from 1:1 to 1:50.

A photocatalyst includes a composite fiber having at least two crystalline semi-conductors that provide a heterojunction structure in the composite fiber.