Methods for making a supported chromium catalyst are disclosed, and can comprise contacting a silica-coated alumina containing at least 30 wt. % silica with a chromium-containing compound in a liquid, drying, and calcining in an oxidizing atmosphere at a peak temperature of at least 650 C. to form the supported chromium catalyst. The supported chromium catalyst can contain from 0.01 to 20 wt. % chromium, and typically can have a pore volume from 0.5 to 2 mL/g and a BET surface area from 275 to 550 m.sup.2/g. The supported chromium catalyst subsequently can be used to polymerize olefins to produce, for example, ethylene-based homopolymers and copolymers having high molecular weights and broad molecular weight distributions.

A nanostructure is provided that in one embodiment includes a cluster of cylindrical bodies. Each of the cylindrical bodies in the cluster are substantially aligned with one another so that their lengths are substantially parallel. The composition of the cylindrical bodies include tungsten (W) and sulfur (S), and each of the cylindrical bodies has a geometry with at least one dimension that is in the nanoscale. Each cluster of cylindrical bodies may have a width dimension ranging from 0.2 microns to 5.0 microns, and a length greater than 5.0 microns. In some embodiments, the cylindrical bodies are composed of tungsten disulfide (WS.sub.2). In another embodiment the nanolog is a particle comprised of external concentric disulfide layers which encloses internal disulfide folds and regions of oxide. Proportions between disulfide and oxide can be tailored by thermal treatment and/or extent of initial synthesis reaction.

A nanostructure is provided that in one embodiment includes a cluster of cylindrical bodies. Each of the cylindrical bodies in the cluster are substantially aligned with one another so that their lengths are substantially parallel. The composition of the cylindrical bodies include tungsten (W) and sulfur (S), and each of the cylindrical bodies has a geometry with at least one dimension that is in the nanoscale. Each cluster of cylindrical bodies may have a width dimension ranging from 0.2 microns to 5.0 microns, and a length greater than 5.0 microns. In some embodiments, the cylindrical bodies are composed of tungsten disulfide (WS.sub.2). In another embodiment the nanolog is a particle comprised of external concentric disulfide layers which encloses internal disulfide folds and regions of oxide. Proportions between disulfide and oxide can be tailored by thermal treatment and/or extent of initial synthesis reaction.

Systems for mixing a catalyst precursor with a heavy oil feedstock preparatory to hydroprocessing the heavy oil feedstock in a reactor to form an upgraded feedstock. Achieving very good dispersion of the catalyst precursor facilitates and maximizes the advantages of the colloidal or molecular hydroprocessing catalyst. A catalyst precursor and a heavy oil feedstock having a viscosity greater than the viscosity of the catalyst precursor are provided. The catalyst precursor is pre-mixed with a hydrocarbon oil diluent, forming a diluted catalyst precursor. The diluted precursor is then mixed with at least a portion of the heavy oil feedstock so as to form a catalyst precursor-heavy oil feedstock mixture. Finally, the catalyst precursor-heavy oil feedstock mixture is mixed with any remainder of the heavy oil feedstock, resulting in the catalyst precursor being homogeneously dispersed on a colloidal and/or molecular level within the heavy oil feedstock.

Systems for mixing a catalyst precursor with a heavy oil feedstock preparatory to hydroprocessing the heavy oil feedstock in a reactor to form an upgraded feedstock. Achieving very good dispersion of the catalyst precursor facilitates and maximizes the advantages of the colloidal or molecular hydroprocessing catalyst. A catalyst precursor and a heavy oil feedstock having a viscosity greater than the viscosity of the catalyst precursor are provided. The catalyst precursor is pre-mixed with a hydrocarbon oil diluent, forming a diluted catalyst precursor. The diluted precursor is then mixed with at least a portion of the heavy oil feedstock so as to form a catalyst precursor-heavy oil feedstock mixture. Finally, the catalyst precursor-heavy oil feedstock mixture is mixed with any remainder of the heavy oil feedstock, resulting in the catalyst precursor being homogeneously dispersed on a colloidal and/or molecular level within the heavy oil feedstock.

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 catalyst for the dehydrogenation of alkanes to alkenes comprises a catalytically active material supported on a carrier, wherein the catalytically active material is a metallic sulfide (MeS) comprising Fe, Co, Ni, Cu, Mo or W or any combination of two or more metals selected from Pb, Sn, Zn, Fe, Co, Ni, Cu, Mo and W. The catalyst is regenerated in several steps. The dehydrogenation is carried out at a temperature between 450 and 650 C. and a pressure from 0.9 bar below ambient pressure to 5 bar above ambient pressure.

A catalyst for the dehydrogenation of alkanes to alkenes comprises a catalytically active material supported on a carrier, wherein the catalytically active material is a metallic sulfide (MeS) comprising Fe, Co, Ni, Cu, Mo or W or any combination of two or more metals selected from Pb, Sn, Zn, Fe, Co, Ni, Cu, Mo and W. The catalyst is regenerated in several steps. The dehydrogenation is carried out at a temperature between 450 and 650 C. and a pressure from 0.9 bar below ambient pressure to 5 bar above ambient pressure.

The present disclosure relates to a catalyst for slurry phase hydrocracking of refinery residue and a process for its preparation. The present disclosure provides a very simple method for exfoliation of metal sulphide, and a process of that provides effective slurry phase hydrocracking of refinery residue with a high yield.

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.