A method of preparing a pure M1 phase MoVTeNbOx catalyst with a high specific surface area, comprising the following steps: S1) mixing and dissolving a molybdenum-containing compound, a vanadium-containing compound, a tellurium-containing compound, a niobium-containing compound and a protective agent to obtain a precursor-protective agent mixed solution, in which the protective agent is a surfactant or a small molecule organic acid and a salt thereof; S2) subjecting the precursor-protective agent mixed solution to a hydrothermal reaction to separate out a solid; S3) calcining the solid in an air atmosphere, followed by calcining the same in an inert gas, and then performing a hydrogen peroxide purification treatment to obtain a pure M1 phase MoVTeNbOx catalyst. The MoVTeNbOx composite oxide catalyst synthesized by the method has high pore volume and high specific surface area, and exhibits an excellent conversion rate, selectivity, space time yield and stability in the oxidative dehydrogenation reaction of ethane for preparing ethylene.

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

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

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.

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.

Mixed metal oxide catalysts having an amorphous content of not less than 40 wt. % are prepared by calcining the catalyst precursor fully or partially enclosed by a porous material having a melting temperature greater than 600° C. in an inert container including heating the catalyst precursor at a rate from 0.5 to 10° C. per minute from room temperature to a temperature from 370° C. to 540° C. under a stream of pre heated gas chosen from steam and inert gas and mixtures thereof at a pressure of greater than or equal to 1 psig having a temperature from 300° C. to 540° C. and holding the catalyst precursor at that temperature for at least 2 hours and cooling the catalyst precursor to room temperature.

Mixed metal oxide catalysts having an amorphous content of not less than 40 wt. % are prepared by calcining the catalyst precursor fully or partially enclosed by a porous material having a melting temperature greater than 600° C. in an inert container including heating the catalyst precursor at a rate from 0.5 to 10° C. per minute from room temperature to a temperature from 370° C. to 540° C. under a stream of pre heated gas chosen from steam and inert gas and mixtures thereof at a pressure of greater than or equal to 1 psig having a temperature from 300° C. to 540° C. and holding the catalyst precursor at that temperature for at least 2 hours and cooling the catalyst precursor to room temperature.

A novel mixed oxide material is disclosed which contains molybdenum, vanadium, tellurium and niobium and the use of the molybdenum mixed oxide material as catalyst for the oxidative dehydrogenation of ethane to ethene or the oxidation of propane to acrylic acid and a process for producing the mixed oxide material.

A novel mixed oxide material is disclosed which contains molybdenum, vanadium, tellurium and niobium and the use of the molybdenum mixed oxide material as catalyst for the oxidative dehydrogenation of ethane to ethene or the oxidation of propane to acrylic acid and a process for producing the mixed oxide material.

Oxidative dehydrogenation catalysts for converting lower paraffins to alkenes such as ethane to ethylene when prepared as an agglomeration, for example extruded with supports comprising slurries of Nb.sub.2O.sub.5.