587 results about "Synergistic catalysis" patented technology

The invention discloses a high-entropy oxide for synergic nitrogen removal and catalysis as well as a preparation method and application thereof, and belongs to the technical field of material preparation, the high-entropy oxide is a single solid solution phase formed by five or more metal elements of Fe, Co, Ni, Cu, Mn, Ti and Ce and an oxygen element, the configuration entropy of the high-entropy oxide is greater than or equal to 1.5 R, R is a gas constant, and R is an oxygen constant. The mole fraction of each metal element is 0.1-0.3, and the sum of the mole fractions of the metal elements is 1. According to the high-entropy oxide with the synergistic nitrogen removal and catalysis effects and the preparation method and application thereof, a synergistic catalysis system is constructed through the high-entropy oxide and silicon carbide, and the high-entropy oxide has the multiple advantages of being high in nitrogen removal efficiency, high in stability, simple in process, environmentally friendly and wide in application range; the removal rate of total nitrogen and key nitrogen pollutants can reach 90% or above in the seawater high-salt environment, and the environment-friendly emission requirement is met.

The invention provides a cerium oxide photo-thermal synergistic catalytic material loaded with a metal promoter as well as a preparation method and application of the cerium oxide photo-thermal synergistic catalytic material. The cerium oxide photo-thermal synergistic catalytic material loaded with the metal promoter comprises a cerium oxide nanocrystal and the metal promoter loaded on the surface of the cerium oxide nanocrystal, the exposed crystal face of the cerium oxide nanocrystal comprises a {111} crystal face, and the area of the {111} crystal face accounts for more than 50% of the total area of the outer surface of the crystal face; the mass fraction of the metal cocatalyst is 0.1-2wt% of the mass of the cerium oxide. The catalytic material provided by the invention takes cerium oxide with a {111} crystal face as an exposed special crystal face as a carrier, photons can be captured and charges can be separated more efficiently, and phonons further promote deep trap state charge release. Meanwhile, the metal additive is added and cooperates with cerium oxide with exposed special crystal faces for catalysis, so that the catalytic effect is remarkably improved, and efficient catalytic combustion of methane is achieved under the mild condition.

The invention discloses a method for degrading polystyrene (PS) plastic and upgrading and recycling the PS plastic into benzoic acid based on nano MnO2 photocatalytic ozonation, and belongs to the technical field of solid waste recycling. The method comprises the following steps: firstly, mixing PS plastic fragments with nano MnO2 and an organic solvent, then simultaneously introducing ozone into a reaction system at normal temperature and normal pressure, and irradiating with light. Through synergistic catalysis of light and ozone, molecular chains of the PS plastic can be efficiently and selectively broken and oxidized, and finally the PS plastic is directionally converted into benzoic acid with high additional value. After the reaction is finished, a benzoic acid product can be obtained through simple separation, concentration and purification steps. The method provided by the invention realizes high-valued recycling of the waste PS plastic under mild conditions, solves the problems of high energy consumption, complex products, easy generation of secondary pollution and the like in a traditional treatment method, and has the outstanding advantages of green process, efficient reaction, high product value and the like.

The invention provides a method for promoting acquisition of clean fuel by light / sound concerted catalytic degradation of waste plastics and upgrading and conversion thereof, which comprises the following steps: uniformly mixing g-C3N4, cadmium acetate and thioacetamide according to a predetermined proportion, pouring into a reaction kettle, placing in a high-temperature oven for a predetermined time, centrifuging, cleaning and drying to obtain a catalyst, the method comprises the following steps: loading a catalyst on the surface of aerogel, hydrogel or non-woven fabric to obtain an MTSJA-loaded catalyst, treating waste plastic with NaOH, adding the MTSJA-loaded catalyst, stirring under irradiation of a xenon lamp, starting ultrasound for reaction, and carrying out light / sound synergistic catalytic degradation on the waste plastic. According to the method, energy consumption is not needed, toxic and harmful gas is not generated, the purposes of energy conservation and environmental protection can be achieved, meanwhile, carbon dioxide in water can be catalytically reduced to generate clean energy such as methane in the process of degrading the waste plastic, and further obtaining of the energy is promoted.

The invention discloses an immunosensor for detecting cytokine interferon gamma through electrochemiluminescence as well as a preparation method and application of the immunosensor. The immunosensor comprises a three-electrode system consisting of an immunoelectrode, a reference electrode and a counter electrode, the immunoelectrode is a VMSF modified electrode confined to cerium dioxide nano enzyme and platinum nano particles, and is obtained by covalently immobilizing an IFN-gamma antibody and closing a non-specific site; when the immunosensor is used for detection, a solution containing luminol is used as an electrolyte. The CeO2 and the PtNPs which are confined in the nano channel show a remarkable synergistic catalysis effect. Compared with direct modification on a plate electrode, CeO2-PtNPs has higher catalytic activity and stability. The sensor provided by the invention is used for INF-gamma detection, has the advantages of high sensitivity, low detection limit and wide detection range, does not need complex pretreatment and separation processes during detection, reduces the detection cost, is simple to operate, and is suitable for large-scale application.

The invention provides a ceramic fiber tube and a preparation method thereof, the ceramic fiber tube is provided with a tube body, the tube body is provided with multiple fiber filter paper layers formed by overlapping fiber cotton layers, and the tube body comprises a denitration area and a CO removal area which are arranged along the wall thickness direction; the denitration area comprises a fiber filter paper layers, the CO removal area comprises b fiber filter paper layers, and a + b is greater than or equal to 100; the pipe body is overlapped between the adjacent fiber filter paper layers to form nanoscale pores, and the pore diameter of the nanoscale pores is 10-50nm; and the CO removal area at least further comprises a CO catalyst which is loaded in the pores and on the surface of the fiber cotton in a nano-scale manner. Different active components are loaded on the carrier structure according to functional areas, and the number of layers of the fiber filter paper layers and nanoscale pores are configured, so that the three-in-one design of partition loading, gradient pores and collaborative catalysis is realized, the technical bottleneck of collaborative purification of multiple pollutants in complex flue gas is overcome, and the application prospect is wide. And high efficiency, economical efficiency and long service life are achieved.

The invention discloses a method for detecting glucose on the basis of cascade catalysis of cerium dioxide / gold nano cluster-Prussian blue nano enzyme (AuNCs-CeO-HMPB). The material is prepared by compounding cerium dioxide (CeO) with similar glucose oxidase activity and hollow Prussian blue nanoparticles (AuNCs-HMPB) modified by gold nanoclusters with similar peroxidase activity through a hydrothermal assembly method. In the presence of glucose, CeO catalyzes oxidation of glucose to generate gluconic acid and H2O2, then AuNCs-HMPB synergistically catalyzes decomposition of newly generated H2O2 to generate high active oxygen species, further a colorless 3, 3 ', 5, 5'-tetramethyl benzidine (TMB) color developing agent is oxidized to generate obvious color change, and based on the cascade catalytic reaction, the enzyme-free glucose colorimetric sensor is successfully constructed. The sensor shows excellent detection performance on glucose under optimized conditions (pH = 4.0, 50 DEG C), the linear detection range is 10.00-90.00 [mu] mol / L, and the detection limit is 2.1 [mu] mol / L (S / N = 3).

The invention discloses a microwave catalysis and plasma combined waste gas treatment system and method. The system is formed by connecting a pretreatment module, a pretreatment cavity module, a main catalysis cavity module, a tail end purification module and an intelligent control module in series. The pretreatment module adopts two-stage condensation and multi-stage dust removal and is provided with a humidity particle return valve; the pretreatment cavity completes low-temperature oxidation under the cooperation of multi-frequency microwaves and a catalyst; the main catalytic cavity integrates a pulse corona-enhanced plasma discharge structure and a 2.45 / 5.80 GHz double-frequency microwave source, and cooperates with a catalyst to deeply crack VOCs. The tail end module achieves waste heat recovery and fine purification through double heat exchangers and double activated carbon adsorption, and a terminal monitors emission online through Fourier infrared. And the intelligent control module predicts and adjusts the microwave power, the discharge frequency and the valve position in real time based on a long short-term memory (LSTM) network algorithm, namely LSTM, so that the system keeps high-efficiency, low-energy-consumption and stable operation under the conditions of high humidity and multi-component VOCs (Volatile Organic Compounds).

The invention discloses a preparation method and application of a catalyst based on pyridine ionic liquid, and belongs to the technical field of catalyst preparation. According to the invention, a hydrolysis reaction of a silane coupling agent is utilized to prepare a silicon oxide nanotube containing a pyridine unit, and then a quaternization reaction is carried out to obtain the catalyst based on the pyridine ionic liquid. The catalyst has a high specific surface area and a rich pore channel structure, exposure of active sites and contact of the active sites and reactants are facilitated, and the catalytic rate is increased. Meanwhile, the silicon oxide nanotube contains hydroxyl, and can cooperate with a pyridine ionic liquid site to catalyze a carbon dioxide cycloaddition reaction. The obtained catalyst can catalyze the reaction of carbon dioxide and an epoxy compound to prepare cyclic carbonate under solvent-free and metal-free conditions, and the catalyst is easy to recover and simple in product purification, and has a good application prospect.

The invention provides a method for preparing rare ginsenoside through conversion of kombucha, the rare ginsenoside and application, and belongs to the technical field of biological medicine. A symbiotic system is formed by multiple bacteria such as acetic acid bacteria, gluconacetobacter, foal bacillus and the like and fungi, after the symbiotic system is domesticated, the American ginseng stem and leaf extract is fermented through multi-bacteria synergistic catalysis, the rare ginsenoside can be efficiently prepared, the highest conversion rate of Rb3 and Rd can reach about 90%, and the yield of Rb3 and Rd can reach about 90%. Meanwhile, the contents of rare ginsenosides Rg3 (20S), Rg5, Rh2 (20R) and Rh2 (20S) are remarkably increased and are increased by about 15 times at most, and efficient conversion of various ginsenosides is achieved.

The invention belongs to the technical field of chemical synthesis, and discloses a method for synthesizing cyclic carbonate through urea alcoholysis under photo-thermal synergistic catalysis. Uniformly mixing the mixed solution of methanol and ionic liquid, zinc salt and other metal salts, and reacting; and after the reaction is finished, centrifugally separating a product, washing, drying, and calcining to obtain the zinc-based homojunction photo-thermal catalyst. The method comprises the following steps: mixing urea, dihydric alcohol and a zinc-based homojunction photo-thermal catalyst, and reacting for 1-6 hours under the conditions that the light intensity is 1-150 mW / cm, the temperature is 130-160 DEG C and the pressure is 5-30 kPa to obtain the cyclic carbonate. The catalyst used in the method effectively overcomes the limitations of low target product synthesis efficiency and high reaction energy barrier in single thermocatalysis, and the yield of the synthesized cyclic carbonate can reach up to 84.1%. Through light energy excitation coupling thermocatalysis, the harshness of reaction conditions is significantly reduced, and efficient synthesis of cyclic carbonate under mild conditions is realized.

The invention belongs to the technical field of composite catalysts, and particularly discloses a metal composite catalyst constructed based on a metal phenolic complex-crystalline porous material as well as a preparation method and application of the metal composite catalyst. The preparation method comprises the following steps: mixing a polyphenol solution and an organic salt solution, and carrying out coordination complexation reaction to obtain a metal phenolic complex; sequentially carrying out first reaction and second reaction on the metal phenolic complex solution and the crystalline porous material precursor solution to obtain a metal phenolic complex-crystalline porous material core-shell structure compound; and then blending with an inorganic metal salt solution, and sequentially carrying out reduction reaction and centrifugal separation to obtain the metal composite catalyst. The hierarchical porous structure and the metal-organic concerted catalysis interface are constructed through interface coordination engineering, and the method has wide application in the fields of electro-catalysis, electro-biological coupling catalysis systems, photo-thermal sterilization and the like. The catalyst is mild in preparation process condition, controllable in structure and suitable for large-scale production.

The present application provides a transition metal single atom carbon-based catalyst, characterized by comprising a transition metal single atom, a nitrogen-doped carbon substrate and an oxygen-doped carbon substrate, and the carbon-based catalyst comprises a 4-coordination structure unit M-N4 structure and a 5-coordination structure unit M-N2O3 structure of the transition metal single atom in the structure of the carbon-based catalyst. The carbon-based catalyst also has high conductivity, and the existence of the two coordination structures can synergistically catalyze the oxidative dehydrogenation of organic matter and the efficient reduction of hydrogen peroxide and oxygen to generate hydroxyl radicals and superoxide radical active species. The synergistic oxidation of the two free radicals on the organic matter in water can significantly improve the mineralization degree of the organic pollutants, thereby efficiently catalyzing the degradation of the organic pollutants in water. The present application also provides a method for preparing the carbon-based catalyst.

The invention discloses a bio-oil enhanced hydrodenitrogenation method, which comprises the following steps: adding bio-oil, a catalyst, formic acid and deionized water into a reaction kettle, uniformly stirring to obtain a mixed solution, continuously stirring for reaction, and after the reaction is finished, carrying out suction filtration and distillation to obtain reformed bio-oil. The preparation method of the catalyst comprises the following steps: mixing corn straw and ammonium molybdate, adding deionized water after mixing, stirring and dipping, and then carrying out vacuum drying and calcining to obtain the catalyst. In the catalytic reforming process, formic acid is innovatively introduced to serve as a hydrogen source, the gas-liquid interface transmission resistance of a traditional gaseous hydrogen source is eliminated through the homogeneous hydrogen supply characteristic of liquid formic acid, the flammable and explosive risk of high-pressure hydrogen is avoided, the process safety is improved, meanwhile, formic acid is subjected to in-situ decomposition on the surface of the catalyst to generate active hydrogen species, and the catalytic reforming efficiency is improved. And a synergistic catalysis mechanism is formed with a platinum-like active site of the catalyst, so that the kinetic advantage of the hydrodenitrification reaction is enhanced, and an efficient, safe and environment-friendly bio-oil hydrodenitrification process system is constructed.

The invention provides a preparation method of a MoS2 / MXene moire heterogeneous synergistic catalyst, which comprises the following preparation steps: selectively etching a Ti3AlC2 precursor by adopting LiF and HCl to obtain a two-dimensional MXene nanosheet; the preparation method comprises the following steps: mixing an MXene solution with Na2MoO4, CH4N2S and citric acid in proportion, and ultrasonically dispersing in a water solvent to form a precursor solution; by regulating and controlling the proportion of the 1T / 2H-MoS2 phase, the conductivity and the stability are both considered, and the synergistic effect of the MoS2 as an electrocatalytic active phase is improved; the orientation and the torsional angle of MoS2 are regulated and controlled on a two-dimensional MXene substrate, a periodic Moire superlattice structure is constructed, and electron coupling and energy band alignment are enhanced; by constructing a collaborative interface system, the transmission rate of interface carriers is increased, the reaction overpotential is reduced, and the durability and cycling stability under high current density are enhanced; the invention provides an extensible and universal flexible preparation method which is suitable for a low-temperature-condition controllable synthesis process for constructing a two-dimensional MoS2 / MXene heterostructure in a large area.

This invention discloses a solution-based synergistic catalytic method for preparing post-functionalized polyolefins, belonging to the field of polymer material modification technology. The method includes the following preparation steps: adding polyolefin, graft monomer, and catalyst to an organic solvent, stirring until homogeneous, and heating to react, thereby obtaining the post-functionalized polyolefin; wherein the catalyst is a combination of a first catalyst and a second catalyst; and the first catalyst is selected from tert-butyl nitrite, and the second catalyst is selected from N-hydroxysuccinimide and / or N-hydroxyphthalimide. This invention utilizes a synergistic catalytic system composed of tert-butyl nitrite and N-hydroxysuccinimide and / or N-hydroxyphthalimide to activate the C-H bonds of polyolefins in an organic solvent via a free radical mechanism, thereby grafting polar functionalized graft monomers onto the main chain of various polyolefins.

The invention relates to the field of comprehensive utilization of biomass energy, and particularly discloses a process for preparing biological coal based on atmospheric distillation of biochar and biological oil, which comprises the following steps: performing atmospheric distillation on unpickled biochar or pickled biochar and biological oil to finally obtain light fraction and biological coal; biochar which is not subjected to acid pickling or biochar subjected to acid pickling serves as an in-situ catalyst, rich pores and oxygen-containing functional groups of the biochar can synergistically catalyze bio-oil to be subjected to condensation polymerization such as esterification and etherification, and finally the prepared bio-coal is good in combustion performance and high in productivity; the process is simple and controllable, and large-scale industrial production is expected to be carried out.

The invention relates to the technical field of organic synthesis, in particular to a method for synthesizing cyclopentane compounds through [3 + 2] cycloaddition reaction of aryl cyclopropane and olefin under the synergistic catalysis of bromide ions / visible light. The method comprises the following steps: in a nitrogen atmosphere, sequentially adding aryl cyclopropane, a benzyl malononitrile derivative, pyridine tribromide and a photocatalyst into a reaction solvent to obtain a mixture, stirring the mixture at the temperature of 40 DEG C under the irradiation of a 12W blue light LED lamp until the reaction is complete, and performing concentration and column chromatography purification to obtain the cyclopentane compound. The method has the advantages of mild reaction conditions, simple operation, simple and easily available raw materials and low cost.

The invention discloses a catalyst for preparing a C4 + oxygen-containing compound through catalytic conversion of ethanol and a preparation method and application thereof, and belongs to a catalyst technology. The catalyst is composed of a carrier and an active component, the carrier is spinel metal oxide AB2O4, and has high specific surface area, rich pore structure and uniform particle size; the active component is high-dispersion metal M, and the metal M accounts for 0.1-5% of the total mass of the catalyst. The preparation method of the catalyst comprises the following steps: preparing the carrier, and anchoring the active component on the carrier in a highly dispersed manner in a molten salt in-situ loading manner, so that the active component of the catalyst and the carrier form a strong synergistic catalysis effect, and the catalyst has the characteristics of high activity and high stability. Under the reaction conditions that the pressure is 3.0 MPa, the temperature is 250 DEG C and the air speed is 3.0 h <-1 >, the selectivity for preparing the C4 < + > oxygen-containing compound through ethanol conversion is as high as 97.6%, and obvious inactivation can be avoided after 200 hours of stable operation.

The application provides a denitration and CVOCs removal encapsulated bifunctional molecular sieve catalyst and a preparation method and application thereof. y The composite nanoparticle is a core, and the hierarchical porous molecular sieve is a shell layer x -BO y The hierarchical porous-zeolite bifunctional molecular sieve catalyst is prepared by coupling two methods of reverse microemulsion and one-pot two-step dry gel conversion. The catalyst exhibits excellent NO x / CVOCs cooperative catalytic removal activity and stability in a medium-low temperature range (180-520 DEG C), and is suitable for simultaneous purification and removal of NO x and CVOCs in flue gas of waste incineration power generation and hazardous waste incineration pyrolysis industries. The catalyst preparation method is simple, can improve the flue gas pollutant purification efficiency, reduce the industry operation energy consumption and save the production cost.

The application discloses an engine exhaust treatment method and device. A target catalyst is obtained, and an active component of the target catalyst comprises cobalt Co, chromium Cr and indium In. The target catalyst is placed in a synergistic catalytic reactor. Then, engine exhaust containing CH4 and nitrogen oxide NO X is introduced into the synergistic catalytic reactor to perform exhaust treatment. During the exhaust treatment, CH4 is converted into carbon dioxide CO2 and water H2O, and NO X is converted into nitrogen N2 based on the action of the target catalyst. Finally, the engine exhaust after the exhaust treatment is discharged from the synergistic catalytic reactor. It can be seen that, for the engine exhaust containing CH4 and NO X , only the synergistic catalytic reactor is arranged as the exhaust treatment system, CH4 and NO X can be treated simultaneously under the action of the target catalyst, and the purposes of simultaneously removing CH4 and NO X are achieved. That is, a mode of synergistically treating CH4 and NO X by using one set of exhaust treatment system is provided, and the engine exhaust treatment system can be simplified, and the exhaust treatment cost is reduced.

The invention discloses a method for synthesizing a benzodithiepinone derivative through metal-free catalysis, and belongs to the field of organic synthesis. According to the method, benzo disulfonylphenol ketone and alkyne are taken as raw materials, a dual-catalysis system composed of triethylene diamine and bis (diphenylphosphine) methane is adopted, a heating reaction is performed in a 1, 4-dioxane solvent, and the target seven-membered sulfur heterocycle (benzo [e] [1, 4] dithiepin-5-ketone compound) is obtained through separation and purification. According to the method, the problem of regioselective sulfuration of alkyne is effectively solved through a synergistic catalysis mechanism of organic amine and organic phosphine, and high-precision cyclization reaction of benzobissulfonylphenol ketone and alkyne is realized. The process is mild in reaction condition, free of inert gas protection, simple and convenient to operate and good in functional group tolerance, the atom economy can reach 100%, and an efficient and practical synthesis way is provided for construction of the benzo [e] [1, 4] dithiepin-5-ketone compound with a novel structure.

The present application relates to a kind of catalyst composition and its application in catalytic preparation optically active secondary alcohol, the catalyst composition includes chiral ionic bridged aryloxyalkane rare earth complex and additive, the additive is selected from one or more of pyrimidine, N,N-dicyclohexylmethylamine, 4,4'-dipyridyl.The above-mentioned catalyst composition can be used for synergistically catalyzing asymmetric borohydration of chalcone and its derivatives with pinacol borane, and show high catalytic activity and high enantioselectivity, product yield is as high as 99%, ee value can reach 84%, provide a reliable new way for the efficient, high selective synthesis of optically active secondary alcohol.

The invention relates to the technical field of organic synthesis, and discloses a synthesis method of fatty acyl chloride, which is characterized in that fatty acid and oxalyl chloride are used as raw materials and are subjected to temperature control reaction in an organic solvent under the action of a composite catalyst to prepare the fatty acyl chloride. Through the synergistic catalysis of the composite catalyst, the reaction activation energy is remarkably reduced, the reaction time is shortened, and the acylation reaction selectivity is improved; meanwhile, reaction process parameters are optimized, the problems of raw material waste and complicated post-treatment caused by excessive oxalyl chloride in a traditional method are avoided, and the product yield and purity are relatively high. The method is easy and convenient to operate, mild in condition, environmentally friendly, suitable for acylating chlorination reaction of straight-chain or branched-chain fatty acid and capable of achieving large-scale industrial production.

The invention relates to the technical field of seawater decomposition, in particular to a molybdenum-based bifunctional catalytic electrode for seawater decomposition and a preparation method of the molybdenum-based bifunctional catalytic electrode. Conventional seawater decomposition hydrogen production or oxygen production highly depends on a noble metal electrocatalyst, the cost is high, and large-scale industrialization of seawater decomposition hydrogen production or oxygen production is greatly limited. In order to solve the technical problems, the molybdenum-based bifunctional catalytic electrode for seawater decomposition is provided, a CP / MoP composite structure is constructed on an NF substrate through phosphating treatment, Ru is combined for dipping and loading modification, a multi-component synergistic catalytic system is formed, bifunctional catalysis is achieved, and the HER overpotential of the electrode can be reduced to lt in an alkaline seawater medium; 60 mV ((at) 10 mA / cm), and OER overpotential lt; the catalyst has the advantages that the catalyst is less than 170 mV (at10mA / cm), is obviously superior to a non-noble metal catalyst and is close to the level of a noble metal-based catalyst, and the electrolysis energy consumption and the production cost are greatly reduced.

The application discloses a preparation method of a mesoporous silicon-based composite material with phosphotungstic acid and titanium oxide simultaneously supported, and belongs to the technical field of catalytic material preparation. The method aims to solve the problems of easy aggregation of active components, easy damage of channel order and complex preparation process in the prior art. The method is characterized by the following steps: through a one-step hydrothermal synthesis strategy, a triblock copolymer is used as a structure directing agent, an alcohol solution of a titanium source precursor, a silicon source precursor and a Keggin type phosphotungstic acid is simultaneously added in an acid system, and then the mesoporous silicon-based composite material is prepared through hydrothermal crystallization, washing, drying and calcination. The method is simple in process and controllable in operation, and the obtained material has the following advantages: two-dimensional hexagonal ordered mesoporous structure, large specific surface area, high dispersion of titanium and phosphotungstic acid, intact Keggin structure, good double-acid-site synergistic catalytic effect, and suitability for acid catalytic reactions, especially in the field of biomass conversion.

The application discloses a method for regionally selective C3-H alkyne of triazolopyridazine compounds, and belongs to the field of organic synthesis. The method uses triazolopyridazine and high-valence iodine (III) alkyne reagent as raw materials, and a double catalytic system composed of Ph3PAuNTf2 (5 mol%), AgOTf (5 mol%) and 1,10-phenanthroline (20 mol%) in dichloromethane, and after reaction at 50 DEG C, the C3 alkyne product is obtained through purification. The method solves the problems of catalyst deactivation and poor selectivity caused by nitrogen-rich heterocyclic rings through gold / silver synergistic catalysis, and realizes precise functionalization of the C3 position. The reaction condition is mild, the substrate is widely applicable (R¹ contains various aryl groups and heteroaryl groups, and R² is compatible with different substituted aryl groups), the yield is 60% to 95%, the step is economical, and the method is suitable for large-scale preparation.

The invention relates to a high-activity catalyst for synthesizing propylene carbonate from CO2 and epoxypropane and a preparation method and application thereof.The catalyst comprises a molecular sieve and metal oxide loaded on the molecular sieve, the molecular sieve is a pure silicon molecular sieve, the metal oxide is one or a combination of more of ZnO, Fe2O3, NiO, CoO and Cr2O3, the metal content accounts for 1-7 wt% of the mass of the catalyst, and the metal content accounts for 1-5 wt% of the mass of the catalyst. The particle size of the catalyst is 0.1-4 [mu] m. The preparation method comprises the following steps: treating a molecular sieve with an organic alkali, dipping the treated molecular sieve in a metal precursor solution subjected to acid treatment, controlling the pH value of the prepared metal precursor solution to be 2-4, shaking with an orbital shaking table, standing, drying, and roasting to obtain the catalyst. According to the invention, rich silicon hydroxyl nest sites on the surface of the molecular sieve with small particle size are utilized to effectively anchor metal species, and under the appropriate metal loading capacity, the synergistic catalysis of the metal and the adjacent silicon hydroxyl sites enables the molecular sieve to have high reaction performance for synthesizing propylene carbonate from CO2 and epoxypropane.

The invention relates to the technical field of nano-materials, and discloses a heterogeneous diatomic nano-enzyme as well as a preparation method and application thereof. The invention provides a space confinement regulation and control strategy which is used for constructing a heterodiatomic catalytic center on a nitrogen-doped carbon skeleton and preparing nano-enzyme with structural stability and synergistic catalytic performance. According to the method, a confinement framework formed by self-assembly of first metal ions such as cobalt ions and second metal ions such as zinc ions and organic ligands is used as a template, third metal ions such as iron ions are introduced, and then carbonization heat treatment is performed in a protective gas atmosphere, so that bimetal sites with stable bridging configuration are formed in situ. The obtained nano-enzyme has the catalytic activity of various antioxidant enzymes, including catalase and remarkable superoxide dismutase activity, and has more excellent free radical scavenging capacity compared with a single-metal or non-bridging system.

The invention discloses an intelligent treatment system for multi-stage microwave catalytic degradation of VOCs, and relates to the technical field of concrete crack detection, and the intelligent treatment system comprises the following specific steps: (1) waste pretreatment, (2) concerted catalytic degradation, and (3) tail gas monitoring and emission. According to the intelligent treatment system for multi-stage microwave catalytic degradation of VOCs, during waste gas pretreatment, waste gas is adjusted to the optimal reaction temperature and humidity, and subsequent waste gas reaction is facilitated; during synergistic catalytic degradation, synergistic treatment of plasma reaction and multi-stage microwave catalytic reaction is adopted, the reaction effect and degradation efficiency of waste gas are improved, complex VOCs waste gas is subjected to classified treatment through multi-stage labor division, a microwave catalytic reactor is divided into a first-stage treatment section, a middle treatment section and a tail-stage treatment section, and the treatment efficiency is improved. Meanwhile, the middle treatment section is further divided into a low-temperature chamber, a medium-high-temperature chamber and a high-temperature chamber, and the problem that complex VOCs are not thoroughly degraded through traditional single-section catalysis is conveniently solved through multi-stage catalytic degradation of the multiple treatment sections.