Provided in this disclosure are oxidative dehydrogenation catalysts that include a mixed metal oxide having the empirical formula:

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

wherein d is a number to satisfy the valence of the oxide. The oxidative dehydrogenation catalyst is characterized by having XRD diffraction peaks (2 degrees) at 220.2, 270.2, 28.00.2, and 28.30.1. The disclosure also provides methods of making the catalysts that include wet ball milling.

The present disclosure relates to a composition that includes, in order: a first layer that includes MA.sub.w; a second layer that includes MO.sub.yA.sub.z; and a third layer that includes MO.sub.x, where M includes a transition metal, A includes at least one of sulfur, selenium, and/or tellurium, w is between greater than zero and less than or equal to five, x is between greater than zero and less than or equal to five, y is between greater than zero and less than or equal to five, and z is between greater than zero and less than or equal to five. In some embodiments of the present disclosure, the transition metal may include at least one of molybdenum and/or tungsten. In some embodiments of the present disclosure, A may be sulfur.

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.

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 template-assisted method for the synthesis of 2D nanosheets comprises growing a 2D material on the surface of a nanoparticle substrate that acts as a template for nanosheet growth. The 2D nanosheets may then be released from the template surface, e.g. via chemical intercalation and exfoliation, purified, and the templates may be reused.

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.

Photocatalysts for reduction of carbon dioxide and water are provided that can be tuned to produce certain reaction products, including hydrogen, alcohol, aldehyde, and/or hydrocarbon products. These photocatalysts can form artificial photosystems and can be incorporated into devices that reduce carbon dioxide and water for production of various fuels. Doped wide-bandgap semiconductor nanotubes are provided along with synthesis methods. A variety of optical, electronic and magnetic dopants (substitutional and interstitial, energetically shallow and deep) are incorporated into hollow nanotubes, ranging from a few dopants to heavily-doped semiconductors. The resulting wide-bandgap nanotubes, with desired electronic (p- or n-doped), optical (ultraviolet bandgap to infrared absorption in co-doped nanotubes), and magnetic (from paramagnetic to ferromagnetic) properties, can be used in photovoltaics, display technologies, photocatalysis, and spintronic applications.