A photocatalyst is described that is suitable for converting molecular nitrogen into ammonia. The photocatalyst comprises a layered base material comprising 1 to 100 layers, the layered base material being selected from the group consisting of molybdenum disulfide, tungsten disulfide, molybdenum telluride, tungsten telluride, molybdenum selenide and tungsten selenide, a layered base material comprising 1 to 100 layers, the layered base material being selected from the group consisting of molybdenum disulfide, tungsten disulfide, molybdenum telluride, tungsten telluride, molybdenum selenide and tungsten selenide, and 0.1-10.0% by weight, relative to the weight of the base material, of one or more Group VI, VII, VIII, IX or X transition metals. T he photocatalyst can further comprise 0.1-50.0% by weight, relative to the weight of the base material, of one or more semiconductor materials having an average particle size of 0.5-50.0 nm. The photocatalyst exhibits high catalytic efficiency without the need for high temperature and pressure. Also described is a process for the preparation of the photocatalyst, as well as uses of the photocatalyst for converting molecular nitrogen into ammonia.

A piezoelectric and piezocata lytic composite material comprising M0S.sub.2 nanoflowers embedded within a body of polyvinylidene difluoride (PVDF) is provided along with layers, coatings, and sheets comprising such a material. Also disclosed are methods of using such material for generating piezoelectricity and for piezocata lytic removal of contaminants from an aqueous environment. A method of forming such material is also described.

A piezoelectric and piezocata lytic composite material comprising M0S.sub.2 nanoflowers embedded within a body of polyvinylidene difluoride (PVDF) is provided along with layers, coatings, and sheets comprising such a material. Also disclosed are methods of using such material for generating piezoelectricity and for piezocata lytic removal of contaminants from an aqueous environment. A method of forming such material is also described.

An ebullated bed hydroprocessing system is upgraded and operated at modified conditions using a dual catalyst system to produce less fouling sediment. The less fouling sediment produced by the upgraded ebullated bed reactor reduces the rate of equipment fouling at any given sediment production rate and/or concentration compared to the sediment produced by the ebullated bed reactor prior to upgrading. In some cases, sediment production rate and/or concentration are maintained or increased, after upgrading the ebullated bed reactor, while equipment fouling is reduced. In other cases, sediment production rate and/or concentration are increased, after upgrading the ebullated bed reactor, without increasing equipment fouling. In some cases, sediment production rate and/or concentration are decreased by a given percentage, after upgrading the ebullated bed reactor, and the rate of equipment fouling is decreased by a substantially greater percentage.

An ebullated bed hydroprocessing system is upgraded and operated at modified conditions using a dual catalyst system to produce less fouling sediment. The less fouling sediment produced by the upgraded ebullated bed reactor reduces the rate of equipment fouling at any given sediment production rate and/or concentration compared to the sediment produced by the ebullated bed reactor prior to upgrading. In some cases, sediment production rate and/or concentration are maintained or increased, after upgrading the ebullated bed reactor, while equipment fouling is reduced. In other cases, sediment production rate and/or concentration are increased, after upgrading the ebullated bed reactor, without increasing equipment fouling. In some cases, sediment production rate and/or concentration are decreased by a given percentage, after upgrading the ebullated bed reactor, and the rate of equipment fouling is decreased by a substantially greater percentage.

An electrocatalyst comprises a crumpled transition metal dichalcogenide support loaded with catalytic metal nanoparticles through spontaneous reduction reactions. The support can be prepared by hydrothermal conversion of 2D nanosheets to 3D hierarchically crumpled sheets. As an example, using crumpled MoS.sub.2 as a support, highly tunable Ru loadings were obtained using the electrostatic interaction between MoS.sub.2 and RuCl.sub.3 in solution. Control over Ru loading was leveraged to produce Ru—MoS.sub.2 electrocatalysts that demonstrate different nitrogen reduction reaction activities, and which show varying resistance to electrochemical sintering and deactivation. Further, these high surface area materials can be utilized for many applications, including electrocatalysts, supercapacitors, and batteries.

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.

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.

Disclosed are a catalyst and a preparation method therefor, the catalyst being able to maintain a high production yield of C8 aromatic hydrocarbons in the process of converting a feedstock containing alkyl aromatics to C8 aromatic hydrocarbons such as mixed xylene through disproportionation/transalkylation/dealkylation while reducing a content of ethylbenzene in the products.

A method of synthesizing a doped carbonaceous material includes mixing a carbon precursor material with at least one dopant to form a homogeneous/heterogeneous mixture; and subjecting the mixture to pyrolysis in an inert atmosphere to obtain the doped carbonaceous material. A method of purifying water includes providing an amount of the doped carbonaceous material in the water as a photocatalyst; and illuminating the water containing the doped carbonaceous material with visible light such that under visible light illumination, the doped carbonaceous material generates excitons (electron-hole pairs) and has high electron affinity, which react with oxygen and water adsorbed on its surface forming reactive oxygen species (ROS), such as hydroxyl radicals and superoxide radicals, singlet oxygen, hydrogen peroxide, that, in turn, decompose pollutants and micropollutants.