A catalyst for catalytic oxidation of furfural to prepare maleic acid is composed of a carbon nitride doped with a potassium salt. A method for preparing the catalyst includes mixing the potassium salt, a precursor of the carbon nitride and a solvent to obtain a mixture, and drying and calcining the mixture to obtain the catalyst. A use of the catalyst in catalytic oxidation of furfural to prepare maleic acid, wherein the maleic acid is prepared by the step of oxidizing furfural in a solvent in the presence of the catalyst. The invention has the advantages that by using the method provided by the invention to prepare maleic acid, the conversion rate of furfural can be 99% or more and the yield of maleic acid can be up to 70.40%.

A regeneration method of a nitrogen-containing carbon catalyst includes the following steps: roasting the nitrogen-containing carbon catalyst in a nitrogen-containing atmosphere to obtain a regenerated nitrogen-containing carbon catalyst. The method is a universal method, which is suitable for nitrogen-doped carbon catalysts and can be used to regenerate a nitrogen-containing carbon catalyst for producing vinyl chloride (VC) through 1,2-dichloroethane cracking. The method can greatly reduce the production cost of the catalyst and increase the service life of the catalyst, and a regeneration process thereof is fast, simple, and controllable, and does not require high temperatures.

The present disclosure provides a manufacturing method of a titanium dioxide solution and a titanium dioxide film. The manufacturing method of the titanium dioxide solution includes: mixing choline chloride, urea, boric acid, and titanium tetrachloride to form a first solution, wherein a molar concentration ratio of choline chloride to urea is 1:2, a molar concentration of titanium tetrachloride is 0.2 M to 0.4 M, and weight/volume of boric acid is 5 g/300 ml to 15 g/300 ml; and heating the first solution to form a second solution, wherein the second solution contains carbon/nitrogen doped titanium dioxide. In the manufacturing method of the present disclosure, the deep eutectic solution formed by choline chloride and urea may be used as a solvent, and may also be used as a carbon source and/or a nitrogen source. Therefore, titanium dioxide may be doped with carbon and/or nitrogen during the formation process.

The present invention is in the field of heterogeneous catalysis.

Particularly, the present invention relates to a process for preparing catalysts advantageously usable in the hydrotreatment processes, for example in hydrodesulphurization, hydrodenitrogenation, hydrodearomatization processes of hydrocarbons.

More in particular, the present invention relates to a process for obtaining said catalysts, which comprise mixed oxides of Nickel, Aluminum, Molybdenum and Tungsten and optionally a transition metal Me selected from the group consisting of Zn, Mn, Cd, and a mixture thereof, an organic component C, and possibly an inorganic binder B.

Said mixed oxides comprise an amorphous phase and a pseudo-crystalline phase isostructural to Wolframite.

The present invention further relates to said hydrotreatment catalysts and a hydrotreatment process wherein said catalysts are used.

The technical field of catalysts, in particular to a combined catalyst and a preparation method thereof, and a method for preparing xylene by coupling carbon dioxide hydrogenation with toluene alkylation. The combined catalyst of the present disclosure having a metal oxide and a zeolite. In the present disclosure, the metal oxide is mainly used to reduce carbon dioxide to methanol, and the zeolite is mainly used to react toluene with methanol to produce xylene. When the catalyst of the present disclosure is used to prepare xylene, carbon dioxide and hydrogen can be used as raw materials instead of methanol. Compared with the traditional alkylation of toluene with methanol, this method can avoid the side reaction of methanol to olefins caused by the improper methanol/toluene feeding ratio, and improve the production efficiency of xylene; meanwhile, it can inhibit xylene isomerization and increase p-xylene selectivity in the products.

In some aspects and embodiments, the present application provides a wide range of porous 1-D polymeric graphitic carbon-nitride materials that are atomically doped with binary metals in different morphologies. In some embodiments, the graphitic carbon-nitride materials can be prepared with high mass production from inexpensive and natural abundant precursors. In some embodiments, the materials were used successfully for the oxidation of CO to CO.sub.2 under ambient reaction temperature in addition to the reduction of CO.sub.2 into hydrocarbons. In some embodiments, the materials can be used for practical and large-scale gas conversion for household or industrial applications.

Methods for producing a carbon-free, PGM-free support for PGM catalyst. The catalytic material comprises PGM metals disposed on a carbon-free support which is catalytic but free of PGM.

The present disclosure provides a synthesis method of a g-C.sub.3N.sub.4/C composite material based on a hollyhock stalk, including the following steps: (1) pretreatment of hollyhock stalks; and (2) fabrication of the g-C.sub.3N.sub.4/C composite material. In this method, with the hollyhock stalk as a carbon skeleton, g-C.sub.3N.sub.4 is spread on a template surface to form a laminated layer, and a composite system with a special structure is constructed. Compared with pure phase g-C.sub.3N.sub.4, the composite material substantially increases specific surface area and has a clear interface; the carbon skeleton not only functions as a rigid support, but also increases the electron transfer efficiency of the composite material, thereby improving the separation efficiency of photogenerated carriers and the utilization rate of visible light. Raw materials used in the method are inexpensive and environmentally friendly, which can be used for industrial production and bulk production of eco-friendly materials for harnessing environmental organic pollutants.

A method for CO.sub.2 hydrogenation via the reverse water-gas shift (RWGS) reaction using alkali metal-doped molybdenum carbide, supported on gamma alumina (A-Mo.sub.2C/γ-Al.sub.2O.sub.3, A=K, Na, Li). The A-Mo.sub.2C/γ-Al.sub.2O.sub.3 catalyst is synthesized by co-impregnation of molybdemun and alkali metal precursors onto a γ-Al.sub.2O.sub.3 support. It is then carburized to form the A-Mo.sub.2C/γ-Al.sub.2O.sub.3. Also disclosed is the related catalyst material.

Disclosed is a method for preparing a ternary alloy catalyst with polydopamine coating and a ternary alloy catalyst prepared thereby. The method for preparing a ternary alloy catalyst according to the present disclosure may provide a ternary alloy catalyst with increased resistance to carbon monoxide (CO) poisoning in which polydopamine is utilized as a coating material for a ternary alloy catalyst having a core-shell structure containing platinum to suppress the growth of particles during subsequent high-temperature heat treatment, and nickel (Ni), which is a transition metal, is diffused inside to form a core, thereby effectively preventing elution of nickel under an acidic condition.