Catalyst preparation systems and methods for preparing reduced chromium catalysts are disclosed, and can comprise irradiating a supported chromium catalyst containing hexavalent chromium with a light beam having a wavelength within the UV-visible light spectrum. Such reduced chromium catalysts have improved catalytic activity compared to chromium catalysts reduced by other means. The use of the reduced chromium catalyst in polymerization reactor systems and olefin polymerization processes also is disclosed, resulting in polymers with a higher melt index.

Processes for converting an olefin reactant into a diol compound are disclosed, and these processes include the steps of contacting the olefin reactant and a supported chromium catalyst comprising chromium in a hexavalent oxidation state to reduce at least a portion of the supported chromium catalyst to form a reduced chromium catalyst, and hydrolyzing the reduced chromium catalyst to form a reaction product comprising the diol compound. While being contacted, the olefin reactant and the supported chromium catalyst can be irradiated with a light beam at a wavelength in the UV-visible spectrum. Optionally, these processes can further comprise a step of calcining at least a portion of the reduced chromium catalyst to regenerate the supported chromium catalyst.

Processes for converting an olefin reactant into a diol compound are disclosed, and these processes include the steps of contacting the olefin reactant and a supported chromium catalyst comprising chromium in a hexavalent oxidation state to reduce at least a portion of the supported chromium catalyst to form a reduced chromium catalyst, and hydrolyzing the reduced chromium catalyst to form a reaction product comprising the diol compound. While being contacted, the olefin reactant and the supported chromium catalyst can be irradiated with a light beam at a wavelength in the UV-visible spectrum. Optionally, these processes can further comprise a step of calcining at least a portion of the reduced chromium catalyst to regenerate the supported chromium catalyst.

Catalyst preparation systems and methods for preparing reduced chromium catalysts are disclosed, and can comprise irradiating a supported chromium catalyst containing hexavalent chromium with a light beam having a wavelength within the UV-visible light spectrum. Such reduced chromium catalysts have improved catalytic activity compared to chromium catalysts reduced by other means. The use of the reduced chromium catalyst in polymerization reactor systems and olefin polymerization processes also is disclosed, resulting in polymers with a higher melt index.

The invention concerns a method for the photocatalytic reduction of carbon dioxide carried out in the liquid phase and/or in the gas phase under irradiation using a photocatalyst comprising a support made from alumina or silica or silica-alumina and nanoparticles of molybdenum sulfide or tungsten sulfide having a band gap greater than 2.3 eV, said method comprising the following steps: a) bringing a feedstock containing carbon dioxide and at least one sacrificial compound into contact with said photocatalyst, b) irradiating the photocatalyst with at least one source of irradiation producing at least one wavelength smaller than the width of the band gap of said photocatalyst so as to reduce the carbon dioxide and oxidise the sacrificial compound in the presence of said photocatalyst activated by said source of irradiation, in such a way as to produce an effluent containing, at least in part, C1 or above carbon-containing molecules, different from CO2.

A nanocomposite photocatalyst is provided. The nanocomposite photocatalyst contains a carbon nanomaterial made of amorphous carbon and graphitic carbon, metal oxide nanoparticles disposed on the carbon nanomaterial, and noble metal nanoparticles disposed on the metal oxide nanoparticles and/or the carbon nanomaterial. Also provided is a method of forming the nanocomposite photocatalyst and a method of photodegrading an organic pollutant in water using the nanocomposite photocatalyst and visible light irradiation.

A method and apparatus for: providing a ceria aerogel and copper nanoparticle catalyst, flowing a hydrogen, carbon monoxide, and water vapor source gas from an inlet into contact with the catalyst to produce a product gas, and flowing the product gas to an outlet. The concentration of carbon monoxide in the product gas is no more than 50% of the concentration of carbon monoxide in the source gas. The concentration of hydrogen in the product gas is no less than 90% of the concentration of hydrogen in the source gas.

A nanocomposite photocatalyst is provided. The nanocomposite photocatalyst contains a carbon nanomaterial made of amorphous carbon and graphitic carbon, metal oxide nanoparticles disposed on the carbon nanomaterial, and noble metal nanoparticles disposed on the metal oxide nanoparticles and/or the carbon nanomaterial. Also provided is a method of forming the nanocomposite photocatalyst and a method of photodegrading an organic pollutant in water using the nanocomposite photocatalyst and visible light irradiation.

Processes for converting a hydrocarbon reactant into an alcohol compound and/or a carbonyl compound are disclosed in which the hydrocarbon reactant and a supported transition metal catalyst—containing molybdenum, tungsten, or vanadium—are irradiated with a light beam at a wavelength in the UV-visible spectrum, optionally in an oxidizing atmosphere, to form a reduced transition metal catalyst, followed by hydrolyzing the reduced transition metal catalyst to form a reaction product containing the alcohol compound and/or the carbonyl compound.

Processes for converting a hydrocarbon reactant into an alcohol compound and/or a carbonyl compound are disclosed, and these processes include the steps of irradiating the hydrocarbon reactant and a supported chromium catalyst comprising chromium in a hexavalent oxidation state with a light beam at a wavelength in the UV-visible spectrum to reduce at least a portion of the supported chromium catalyst to form a reduced chromium catalyst, and hydrolyzing the reduced chromium catalyst to form a reaction product comprising the alcohol compound and/or the carbonyl compound. In addition, these processes can further comprise a step of calcining all or a portion of the reduced chromium catalyst to regenerate the supported chromium catalyst.