31results about How to "Improve catalytic selectivity" patented technology

The invention relates to the technical field of photocatalytic processes, in particular to a catalyst for preparing methanol through photocatalytic reduction of CO2 as well as a preparation method and application of the catalyst. The catalyst comprises a composite carrier and active sites dispersed on the surface or in pores of the composite carrier, the composite carrier is of a heterojunction composite structure formed by a hollow TiO2 sphere and MCN, the hollow TiO2 sphere comprises a shell layer and a spherical cavity structure located in the shell layer, the shell layer is formed by TiO2 nanoparticles, and the MCN has a mesoporous pore structure; a II-type or Z-type heterojunction interface is formed between the hollow TiO2 spheres and the MCN through physical contact and chemical action; the active sites comprise copper nano species, sulfur vacancy defects and amino groups; the copper nano species are copper nano particles or clusters, and the valence state of copper is 0 and / or + 1 valence amino is grafted on the surface of the composite carrier through an organic long chain. The catalyst provided by the invention can greatly improve the yield and selectivity of methanol prepared by photocatalytic reduction of carbon dioxide.

The invention discloses a preparation and plasma modification method of a copper-based catalytic electrode, foamy copper is used as a substrate, and after multi-step sequential preparation such as electric activation and hydrothermal treatment, the surface of the electrode is modified by a plasma method to construct a copper-based catalyst. The problem that the stability of a supported copper-based material is insufficient due to falling of an oxide layer and grain growth is effectively solved, the catalytic activity and selectivity of the material are remarkably improved, important support is provided for achievement of a dual-carbon target and promotion of a sustainable development strategy, and outstanding scientific value and wide application prospects are achieved.

The application discloses a polyacid zeolite imidazolate framework loaded monatomic catalyst and a preparation method and application thereof, and belongs to the technical field of catalysts. The preparation method of the catalyst is as follows: (1) preparing a zeolite imidazolate framework material; (2) mixing the dried zeolite imidazolate framework material and a metal salt in a solvent and stirring; then adding a heteropoly acid, controlling the pH in the system to be 5-7, and performing a solvothermal reaction under the condition of 80-120 DEG C; after the reaction is completed, cooling and centrifugal separation are performed to obtain a precipitate; and (3) performing calcination treatment on the precipitate to obtain the polyacid zeolite imidazolate framework loaded monatomic catalyst. The polyacid zeolite imidazolate framework loaded monatomic catalyst prepared by the method has high catalytic activity, high selectivity and good cycle stability, and has a good application prospect in acetyl propionate esterification reaction.

This invention discloses a method for preparing a manganese-based core-shell structured denitrification catalyst for the combined removal of CO and VOCs, and its application, belonging to the field of catalyst technology. The method employs a homogeneous deposition process to introduce iron, copper, silicon, and phosphorus elements onto the surface of a manganese dioxide core, forming corresponding oxide layers to obtain the manganese-based core-shell structured denitrification catalyst. This method is simple, and the resulting catalyst exhibits sulfur resistance at lower temperatures, strong oxidation performance for carbon monoxide and volatile organic compounds, and high selectivity for nitrogen in denitrification at high temperatures. This invention shows broad promise for applications in the combined removal of multiple pollutants.

The application discloses a novel polyhydroxyalkanoate (PHA) polymerase (PhaC) which can efficiently polymerize the activated monomer 6-hydroxyhexanoate-CoA (6HHx-CoA) of 6-hydroxyhexanoate (6HHx). The PhaC is co-expressed with a CoA ligase AlkK, and can synthesize poly-epsilon-caprolactone (PCL) from the direct precursor sodium 6-hydroxyhexanoate in a halomonas sp. Halomonas which has deleted endogenous beta-ketothiolase (PhaA), acetoacetyl-CoA reductase (PhaB), PhaC and enoyl-CoA hydratase (FadB).

The invention relates to a preparation method of a catalyst for preparing acetyl n-propanol through catalytic oxidation of 2-methyltetrahydrofuran, and belongs to the technical field of catalyst preparation. The preparation method specifically comprises the following steps: dissolving a vanadium-containing compound serving as a main component of the catalyst and oxalic acid serving as a pore-forming agent into deionized water; heating and hydrolyzing the solution to completely evaporate water to obtain a solid; and roasting the solid in an air atmosphere to obtain the catalyst. The prepared catalyst is a catalyst for catalyzing molecular oxygen to oxidize 2-methyltetrahydrofuran to prepare acetyl n-propanol, and a new route for preparing acetyl n-propanol is realized.

The application relates to the technical field of catalysts, in particular to a supported catalyst and a preparation method and application thereof. The supported catalyst comprises a carrier and an active component supported on the carrier; wherein the carrier is silicon-modified alumina with a B acid density of less than or equal to 2 micromoles per gram; the dispersity of the active component is greater than or equal to 20 percent; wherein the content of the carrier is 90-99.9 percent by weight and the content of the active component is 0.1-10 percent by weight based on the total weight of the supported catalyst. The supported catalyst provided by the application has high catalytic activity and selectivity; meanwhile, the method provided by the application simplifies the process flow and is convenient for industrial production.

The invention relates to the technical field of catalysts, in particular to a palladium-nickel catalyst for synthesizing vinyl acetate and a preparation method thereof.According to the catalyst, a composite carrier of nanometer aluminum oxide and a ZSM-5 molecular sieve serves as a carrier, Pd and Ni serve as bimetallic main active components, and potassium acetate and La2O3 serve as auxiliary active components. The preparation method comprises the key steps of carrier pretreatment, step-by-step impregnation loading of active components, roasting activation in an acetic acid-containing partial pressure atmosphere and the like. A Pd-Ni system is adopted to replace a traditional expensive Pd-Au system, the cost of precious metal is remarkably reduced by 40%-50%, meanwhile, the catalytic activity, selectivity and stability of the catalyst are comprehensively improved through the synergistic effect of all the components, and the catalyst is particularly suitable for industrial production of synthesizing vinyl acetate through an ethylene gas phase method.

The invention discloses a method for high-efficiency alcoholysis of monomers from waste polyester, and belongs to the field of waste polyester recovery. The method comprises the following steps: firstly, by taking zinc acetate as a metal source and 2-methylimidazole (MI) and 2-ethylimidazole (EI) as organic ligands, coprecipitating at room temperature to form an MOFs precursor, and calcining at 350 DEG C in an air atmosphere to obtain a heterogeneous catalyst with nano ZnO anchored to a nitrogen-doped carbon skeleton, and applying the heterogeneous catalyst to ethylene glycol alcoholysis of waste polyester; the highest alcoholysis effect of the catalyst can reach that the PET conversion rate is 100%, and the BHET yield is 84.9%. The heterogeneous catalyst prepared by the invention has the advantages of high catalytic efficiency, simple preparation, green process and the like, is easy to filter and recover, solves the problems of difficult separation of metal salt, few active sites of metal oxide, easy sintering inactivation and the like, provides a new idea for chemical closed-loop recovery of waste polyester, and has a wide market application prospect.

The application discloses a fibrous nitrogen-doped carbon metal mesh composite membrane for water treatment, which utilizes a metal mesh as a base film and a metal source, uses amino acids as a nitrogen source and a carbon source, and forms a stable nitrogen-doped carbon layer through a calcination process and uniformly distributes the nitrogen-doped carbon layer on the surface of the metal mesh. The application utilizes abundant amino and carboxyl functional groups in amino acid molecules, forms a stable chemical chelate structure with metal ions of the metal mesh base through coordination bonding, and effectively enhances the interfacial bonding strength between the nitrogen-doped carbon and the metal mesh base film in the carbonization process through the bonding mechanism at the molecular level.

This invention belongs to the field of fluorochemical technology, specifically relating to a method for preparing cis-1,1,1,4,4,4-hexafluoro-2-butene. The method includes the following steps: I. Reacting 3,3,3-trifluoropropylene with carbon tetrachloride under light irradiation, optionally in the presence of a first catalyst, to obtain 1,1,1,3-tetrachloro-4,4,4-trifluorobutane; II. Reacting the obtained 1,1,1,3-tetrachloro-4,4,4-trifluorobutane with hydrogen fluoride in the presence of a second catalyst to obtain cis-1,1,1,4,4,4-hexafluoro-2-butene. The first step of this method uses a light-driven addition reaction, and the photocatalytic approach significantly reduces production costs. It can also be combined with a dedicated catalyst to improve reaction efficiency. The second step, the fluorination reaction, is adapted to a specific catalyst, which can effectively improve the conversion rate of the reactants and the selectivity of the target product, ensuring the overall high efficiency of the preparation process.

This invention discloses a Pd nanodendritic structure, its preparation method, and its application. The preparation method includes cutting a glass slide into cubes and washing it; dissolving 1-butylpyridine chloride in chloroform solution, then adding 1-naphthol, and dissolving to prepare a chloroform mixture as the oil phase in the reaction system; preparing a precursor solution as the aqueous phase in the reaction system; placing the glass slide in a cylindrical vial for later use; adding the chloroform mixture to the vial, then adding the precursor solution to form an oil-water two-phase reaction system, and allowing the reaction to stand; extracting the organic phase, transferring the product onto the glass slide, then extracting the aqueous solution, loading the obtained product onto the glass slide, washing and drying it to prepare a Pd nanodendritic structure loaded on a glass slide. The catalyst prepared by this invention through a simple and efficient oil-water interface synthesis method exhibits excellent catalytic activity and selectivity in the selective hydrogenation of p-nitrobenzaldehyde to p-aminobenzaldehyde.

The invention discloses a nano-island confinement iron mononuclear site catalyst and a synthesis method and application thereof, and relates to the technical field of water pollution control and resource recovery, the catalyst takes spheroidal C-Fe0 as a nano-island confinement carrier, urea is introduced as a nitrogen source through a calcination process, and is coordinated with Fe atoms in C-Fe0 to form a FeN4 mononuclear site, and the nano-island confinement iron mononuclear site catalyst is prepared. And a space synergistic effect is formed with the nano island confinement carrier. The preparation method specifically comprises the following steps: dissolving anhydrous sodium acetate in a green tea extracting solution, adding an iron nitrate nonahydrate solution, magnetically stirring, and centrifuging, washing and freeze-drying after the reaction is completed to obtain an iron precursor; the preparation method comprises the following steps: mixing an iron precursor with urea, and roasting in an inert gas environment to obtain the nano island confinement iron mononuclear site catalyst marked as C-Fe0-coated FeN4. According to the catalyst, the co-activation capability of PAA and 2, 6-DCP on a C-Fe0-coated FeN4 interface can be enhanced, 2, 6-DCP is induced to be subjected to an efficient oxidative polymerization reaction, and synchronous emission reduction and carbon resource recovery of 2, 6-DCP are achieved.

The application provides a denitration catalyst, a preparation method and application thereof, and the denitration catalyst comprises a layered MCM molecular sieve carrier and a composite oxide active component loaded on the surface of the layered MCM molecular sieve carrier, and the chemical formula of the composite oxide active component is CeCuO x The denitration catalyst has high surface acidity and redox capacity, the CeCuO x The alkali metal poisoning resistance of the catalyst is improved, so that the catalyst has high catalytic activity and nitrogen selectivity in the use temperature range of 250-400 DEG C after being poisoned by alkali metal.

The application discloses a CO-SCR catalyst, a preparation method and application thereof, and the CO-SCR catalyst comprises a cerium-based composite oxide carrier and a noble metal active component, and the noble metal active component is dispersed on the surface of the cerium-based composite oxide carrier by means of a surfactant. The CO-SCR catalyst utilizes the dispersion and loading of the noble metal assisted by the surfactant, so that the CO-SCR catalyst has higher metal dispersion and redox capacity. Meanwhile, the suitable pH value of the carrier surface is also beneficial to the adsorption of CO and NO, and the low-temperature catalytic activity and high-temperature stability of the catalyst are improved, and the CO-SCR catalyst has higher catalytic activity and nitrogen selectivity in the use temperature range of 250 DEG C to 400 DEG C.

The invention discloses a synthesis method and application of an asymmetric ether compound, and belongs to the technical field of organic synthesis. According to the method disclosed by the invention, stoichiometric silver trifluoromethanesulfonate is taken as a catalyst, benzyl halides with different structures directly react with benzyl alcohol under the conditions of air atmosphere, room temperature and no need of keeping out of light, and the asymmetric ether bond is efficiently constructed. Aromatic groups in the benzyl halide and the benzyl alcohol are independently selected from aryl or five-membered to six-membered heteroaryl containing nitrogen, oxygen and sulfur heteroatoms. The method provided by the invention is mild in condition, safe and simple to operate, wide in substrate applicability, simple in post-treatment and easy for industrial amplification, and the prepared asymmetric ether compound has very high application value in preparation of drugs and pesticides.

The application relates to the technical field of organic synthesis, in particular to a preparation method of biphenol, wherein under visible light irradiation, biphenyl, a catalyst, acetonitrile and hydrogen peroxide are mixed and reacted, then filtered, the obtained filtrate is distilled, and the product is collected, so that the biphenol is prepared; the catalyst is a rare earth doped transition metal organic framework microsphere, the method has mild reaction conditions, is easy to operate, no toxic waste liquid is generated, and a new idea is provided for the preparation of the biphenol.

To address the problems of existing technologies, this invention provides a highly stable catalyst with the structural formula Au / CuO@Cu-NaY. This catalyst is prepared by the following method: Rice husks are cleaned at room temperature to obtain substance A. Substance A is calcined to obtain substance B. Substance B is dissolved in NaOH solution to obtain mixture C, and NaAlO2 is dissolved in deionized water to obtain solution E. A Cu source is added to mixture C to obtain mixture D. Mixture D is added to solution E to obtain mixture J. Mixture J is aged to obtain mixture K. Mixture K is hydrothermally treated to obtain mixture L. Mixture L is washed with water to obtain product Cu-NaY. Cu-NaY is mixed with Au / CuO and ground to obtain the highly stable catalyst. The catalyst prepared by this invention maintains high catalytic activity and selectivity while overcoming the problems of catalyst deactivation and poor stability.

The invention discloses an echelon utilization method of nitrate-containing wastewater, which comprises the following steps: S1, catalyst preparation: preparing a carbon fiber loaded metal particle catalyst by using metal nitrate in the nitrate-containing wastewater through soaking loading and Joule heat treatment; and S2, electrochemical reduction: assembling the catalyst into a membrane electrode assembly, and reducing nitrate ions in the nitrate-containing wastewater used in the step S1 or from another source into ammonia under an electrochemical condition. The method realizes synergetic recycling of metal ions and nitrate ions in the wastewater, forms a closed-loop process of treating waste with waste and turning waste into wealth, has the advantages of no secondary pollution, low cost, stable catalytic performance and capability of producing high-added-value ammonia products, and is suitable for nitrate-containing wastewater treatment in industries such as agriculture, photovoltaics, semiconductors and the like.

The invention belongs to the technical field of catalysts, and particularly discloses a Pd monatomic and nanoparticle synergistic catalyst and a preparation method and application thereof.The active component Pd of the catalyst is loaded on a zirconium phosphate carrier in the forms of monatomic and nanoparticles; the zirconium phosphate carrier is of an amorphous structure, and the specific surface area is 120-180m < 2 > / g; and the mass fraction of the active component Pd in the catalyst is 0.3-3 wt%. The invention solves the problem that the activity, stability and selectivity of the catalyst in the alkyne semi-hydrogenation reaction cannot be combined at the same time through the simple synthesis method.

This invention provides a method for preparing an amorphous porphyrin supramolecular photocatalyst. The method involves synthesizing amorphous porphyrin supramolecular molecules at room temperature using porphyrin monomers as raw materials, and then using these amorphous porphyrin supramolecular molecules as a photocatalyst to prepare hydrogen peroxide. This invention utilizes amorphous porphyrin supramolecular molecules as a photocatalyst, which is convenient and rapid to synthesize. In the hydrogen peroxide preparation process, O2 is used as the oxygen source and visible light as the energy source, resulting in low energy consumption and high safety. The method is green and pollution-free, with mild reaction conditions, and a high yield of hydrogen peroxide per unit time. The yield of hydrogen peroxide prepared by amorphous porphyrin supramolecular molecules as a photocatalyst is approximately twice that of crystalline porphyrin supramolecular molecules. Among these, amorphous TCPP supramolecular molecules exhibit the highest yield of hydrogen peroxide, reaching up to 300 mM / g.

The invention discloses a preparation process of vegetable insulating oil with high oxidation stability, and belongs to the technical field of vegetable oil refining. The core of the process is as follows: firstly, taking palladium and nickel salts in a specific molar ratio as precursors, and combining with polyethylene glycol to prepare a palladium-nickel bimetallic catalyst loaded on alkaline carclazyte; then, vegetable oil is mixed with the catalyst and activated carbon, and hydrogen is introduced under mild vacuum and heating conditions for selective hydrogenation refining; and finally, adding an antioxidant and a pour point depressant into the refined oil to obtain a final product. Through the synergistic effect of the catalyst, extremely unstable linolenic acid in hydrogenated oil can be efficiently and selectively hydrogenated, by means of an integrated process and blending, the oxidation stability is remarkably improved, meanwhile, the excellent low-temperature fluidity of the product is kept, the refining yield is high, the process is simple and convenient, and the method is suitable for large-scale production of the environment-friendly high-performance vegetable insulating oil.

The application discloses a preparation method of a supported shape-preserving nanometal catalyst, which comprises the following steps: 1) preparing a metal nanocrystal dispersion liquid; 2) mixing a carrier with a solvent, then mixing the carrier with the metal nanocrystal dispersion liquid prepared in the step 1), and obtaining an intermediate product after filtration, washing and drying; the carrier is selected from reducible metal oxides or a mixture of reducible metal oxides and inert supports; and 3) sequentially performing oxidation atmosphere calcination, reduction atmosphere calcination and passivation treatment on the intermediate product. The application discloses the preparation method of the supported shape-preserving nanometal catalyst, and the prepared nanometal catalyst has a low proportion of edge and corner atoms, high catalytic selectivity, activity and stability, and can be widely applied in the selective hydrogenation reaction of alkyne compounds.

The invention discloses a preparation method of a gluconic acid modified oxygen evolution electrocatalyst and application of the gluconic acid modified oxygen evolution electrocatalyst in catalysis of seawater oxidation, foamed nickel is placed in deionized water of (NH4) 6Mo7O24. 4H2O and monobasic strong acid for reaction, and then the reacted foamed nickel is placed in a reaction system containing ferrous gluconate to prepare the oxygen evolution electrocatalyst. The oxygen evolution electrocatalyst can form a hydrogen bond on an outer Helmholtz layer through a gluconic acid ligand in a seawater oxidation process, so that the stability of a hydrated potassium ion layer is effectively reduced, and OH <-> is smoothly transferred to an inner Helmholtz layer; meanwhile, the formed hydrogen bond network is beneficial to reducing the dehydrogenation energy barrier in the oxygen evolution reaction process, and the technical problem that the seawater oxygen evolution reaction efficiency is low is solved to a certain extent; charges on the surface of the catalyst can be modified through the reduction effect of gluconic acid, the technical problem that seawater oxidation reaction selectivity is poor is solved, and the method has important significance on development of seawater oxygen evolution electrocatalysts with high selectivity and activity.

The application discloses a kind of microreactor for carbon dioxide conversion in air, including reaction cavity, and reaction cavity shell is made of light transmission glass;Multiple sets of catalyst carrier assemblies are equipped in reaction cavity cavity, along material flow direction, adjacent catalyst carrier assemblies are staggered in turn and form baffle passage;Each set of catalyst carrier assembly is composed of transversely arranged catalyst carrier and longitudinally arranged catalyst carrier;Catalyst carrier is foam ceramic carrier, and catalyst is loaded on carrier, and foam ceramic carrier is porous structure.The application limits reactor, can realize CO2 on foam ceramic carrier in reactor inside sufficient mass transfer and heat transfer, and transversely and longitudinally arranged carrier can increase the residence time of CO2 in foam ceramic pore, and transversely and longitudinally arranged carrier can expose more active sites of catalyst, so that the catalytic efficiency of entire reaction is improved, realizes CO2 100% conversion rate, and also can realize 100% conversion of CO2 in air.

This application discloses a palladium-hydrogen rare earth nanoalloy material, its preparation method, and its application. The palladium-hydrogen rare earth nanoalloy material includes a carbon support and PdREH nanomaterials loaded on the surface of the carbon support. x Nanoparticles, PdREH x The nanoparticles comprise an alloy of Pd and rare earth elements (RE), and hydrogen embedded in the alloy lattice; wherein the rare earth element RE is one of Y, Ce, Sm, Gd, and Tb. This application constructs a nanoalloy material with a stable lattice structure and good hydrogen intercalation capability by forming an alloy of palladium and rare earth elements and further intercalating hydrogen. Simultaneously, by combining a carbon support with a two-step Joule thermal-hydrothermal preparation process, the composition and structure of the material can be controllably adjusted. This material exhibits excellent electrochemical response sensitivity, high ethylamine production capacity, and high Faradaic efficiency in the acidic electrocatalytic hydrogenation of acetonitrile to ethylamine reaction, making it suitable for low-resistance proton exchange membrane devices.

The application discloses a preparation method of a hierarchical pore double-heterojunction catalyst for enhancing photothermal catalytic carbon dioxide reduction, and the catalyst is obtained by confining a heterojunction precursor solution in polystyrene template channels with a three-dimensional ordered multilayer opal structure, and then through simple calcination treatment, a hierarchical pore S-type heterojunction / Schottky junction photothermal catalytic material with a macropore-mesopore structure is obtained. Compared with other zero-dimensional / two-dimensional photothermal catalytic materials, the heterojunction structure is expanded to a three-dimensional hierarchical porous frame structure, and the obtained photothermal catalytic material has unique advantages of controllable structure and adjustable loading, and provides abundant active reaction site centers for a photothermal catalytic process.

This invention provides 13 High-abundance CO was prepared by CuO catalytic oxidation. 13 This invention relates to a CO2 apparatus and method, belonging to the field of stable isotope-labeled compound preparation technology. The apparatus described in this invention is an integrated unit comprising a feed gas supply unit, a fixed-bed reaction unit, a cryogenic collection unit, a partial pressure purification unit, and a tail gas treatment unit connected in series. The fixed-bed reaction unit includes a fixed-bed reactor, a heater, and a temperature sensor. This invention utilizes high-temperature calcined modified CuO catalyst particles, combined with a composite bed structure design of "quartz wool-quartz sand-catalyst-quartz sand," significantly improving conversion efficiency and selectivity; optimizing the purification process, achieving product quality that meets high-end application standards; featuring a novel apparatus design with greatly improved sealing and stability; simple and controllable operation, facilitating industrial scale-up; and being green, safe, and environmentally friendly, aligning with industrial development trends.

The application discloses a supported catalyst, a preparation method and a catalytic reforming method. The supported catalyst comprises a Sn-containing alumina carrier and an active component. The active component comprises Pt. The Pt is dispersed on the Sn-containing alumina carrier in the form of sub-nanometer clusters. The method for preparing the supported catalyst comprises the following steps: (1) adding a Pt precursor into a reducing organic solvent to obtain a first solution; (2) adjusting the pH value of the first solution to 8-14 to obtain a second solution; (3) adding the Sn-containing alumina carrier into the second solution to perform impregnation, drying and calcination, and obtaining an intermediate product; and (4) performing water-chlorine activation and reduction on the intermediate product obtained in the step (3). In the supported catalyst for catalytic reforming reaction, the Pt is dispersed on the Sn-containing alumina carrier in the form of sub-nanometer clusters. The catalyst has better catalytic selectivity and anti-carbon deposition capacity for a naphtha catalytic reforming reaction, and can obviously improve the yield of liquid products.

The present application relates to a kind of tellurium / carbon nitride p-n heterojunction photocatalyst and its preparation method and application, preparation method includes the following steps: S1, tellurium compound and carbon-nitrogen compound are dispersed in deionized water, after ultrasonic mixing sufficiently, precursor homogeneous solution is obtained;S2, precursor homogeneous solution obtained in step S1 is carried out hydrothermal reaction, cooling, centrifugal, washing, drying after obtaining supramolecular intermediate;S3, supramolecular intermediate obtained in step S2 is calcined with gas, and after grinding, tellurium / carbon nitride p-n heterojunction composite photocatalyst powder is obtained.Compared with prior art, the tellurium / carbon nitride p-n heterojunction photocatalyst prepared in the present application realizes the accelerated migration of tellurium conduction band photo-generated electrons to carbon nitride conduction band, and the accelerated migration of carbon nitride valence band photo-generated holes to tellurium valence band, inhibits the recombination of carrier, improves charge separation and migration efficiency, so as to enhance photocatalytic activity.