750 results about "Hydrothermal synthesis" patented technology

The invention relates to the field of optical protection materials, and provides a transparent film with laser eavesdropping prevention performance and a preparation method thereof.The transparent film is composed of surface-modified doped tungsten oxide nanosheets, amino-isocyanate bifunctional lithium niobate nanowires, urethane acrylate, an ultraviolet light absorber, a silane coupling agent, a dispersing agent and a flatting agent; the molybdenum-doped tungsten oxide nanosheets are obtained through silane coupling modification after hydrothermal synthesis, and the lithium niobate nanowires are prepared through a gradient modification process of hydrothermal synthesis-silane coupling-isocyanate grafting-phenol end capping. A modified nano material is uniformly dispersed in a resin matrix through an ultrasonic dispersion composite technology, and through blade coating forming, ultraviolet curing and constant-temperature and constant-humidity post-treatment, compared with the prior art, the scheme overcomes the problems that a traditional protective film is insufficient in optical transparency, laser eavesdropping prevention function and dynamic viscoelasticity, and is suitable for the field of high-end security and protection.

The invention relates to the field of coating materials, and provides a high-wear-resistance stainless steel-based composite coating which is composed of dumbbell-shaped silver-doped silicon carbide, sea urchin-shaped titanium dioxide, 304 stainless steel powder, NiCrBSi nickel-based autolytic alloy powder and the like. The silver-doped silicon carbide is prepared through sol-gel, high-temperature carbonization and acid pickling, and the titanium dioxide filler is obtained through hydrothermal synthesis and calcination. Supersonic flame spraying deposition is adopted, the compactness and bonding strength are enhanced through laser remelting, and finally the wear resistance, the pollution resistance and the antibacterial performance are improved through vacuum annealing, mechanical polishing and hydrophobic coating modification. The design of dumbbell-shaped silver-doped silicon carbide and urchin-shaped titanium dioxide is adopted, high-wear-resistance, antibacterial and high-binding-force coating performance is achieved, the problems of wear resistance and bacteriostasis are solved, and the coating is suitable for the fields of cabinet door plates and the like.

The invention relates to a two-dimensional nano heterojunction with space-time antibacterial and anti-inflammatory functions and a preparation method and application thereof, and belongs to the field of biomedical materials. The preparation method comprises the following steps: firstly, generating a BiCuSeO nanosheet, and resuspending the BiCuSeO nanosheet by using deionized water; the preparation method comprises the following steps: adding cerium nitrate hexahydrate into ethylene glycol, mixing with a BiCuSeO nanosheet resuspended by deionized water, and preparing the two-dimensional nano heterojunction with space-time antibacterial and anti-inflammatory functions by taking the BiCuSeO nanosheet as a seed and the cerium nitrate hexahydrate as a raw material through a hydrothermal synthesis method. Compared with the prior art, good photo-thermal performance of the heterojunction can be utilized, near infrared is used as an external field excitation source to regulate and control the temperature difference and excite the thermoelectric performance of the heterojunction, collaborative treatment of the photo-thermal performance and the thermoelectric performance is achieved, the enhanced anti-inflammatory function of the heterojunction is combined, and the heterojunction becomes a potential application material for infectious bone defects. The preparation method is simple, stable in condition and high in repeatability.

The invention discloses an application of a molybdenum disulfide-based piezoelectric catalytic material in a seawater uranium extraction material, and relates to the technical field of seawater uranium extraction, thiourea and sodium molybdate are used as precursors, and a MoS2 nanoflower with a specific 1T / 2H composite crystal structure is constructed through a hydrothermal synthesis technology. The method is placed in a uranyl nitrate solution, ultrasonic treatment is combined, efficient extraction of uranium can be achieved, and the method has potential application to extraction of uranium from seawater. The method is simple in process and environment-friendly, almost does not generate harmful waste in the synthesis process, does not need complex operation, and has good amplification preparation potential.

The invention discloses a deep fluorine removal agent and application thereof in wastewater in the photovoltaic industry, and belongs to the technical field of fluorine-containing wastewater treatment.The deep fluorine removal agent is obtained by conducting coordination on cross-linked hybrid chitosan microspheres and lanthanum ions to obtain composite microspheres and then synthesizing zirconium-based MOF on the composite microspheres through a hydrothermal synthesis method. The pore channels of the MOF facilitate the passing of fluorine ions but not the passing of sulfate ions, play a certain barrier role, facilitate the enrichment of the fluorine ions on the surfaces of the composite microspheres and the selective adsorption of the lanthanum ions on the fluorine ions, so that the fluorine ions are fixed, and the combination stability of the fluorine ions and the lanthanum ions is greater than that of the sulfate ions. The sulfate ions are in disadvantage when competitive adsorption with the fluorine ions, the selectivity of the deep fluorine removal agent to the fluorine ions is improved, the magnesium ions can be combined with the fluorine ions to generate complexes and can be combined with the sulfate ions to generate soluble magnesium sulfate, and interference of the sulfate ions is reduced through cooperation of the magnesium ions and the sulfate ions.

The invention belongs to the technical field of environment-friendly materials and wastewater treatment, and particularly relates to a tungsten slag-based fluorine removal agent and a preparation method thereof.The preparation method of the tungsten slag-based fluorine removal agent comprises the following steps that S1, tungsten slag and lithium slag are obtained; s2, sequentially drying, grinding and sieving the tungsten slag to obtain a first raw material, and sequentially drying, grinding and sieving the lithium slag to obtain a second raw material; s3, mixing the first raw material, the second raw material and water according to a certain proportion to obtain a slag-water mixture; s4, the slag-water mixture is adjusted to be acidic, the slag-water mixture is subjected to a hydrothermal synthesis reaction, washing and drying are conducted after filtering, and the tungsten slag-based fluorine removal agent is obtained; according to the method, the tungsten slag and the lithium slag are mixed, then the tungsten slag-based fluorine removal agent is synthesized through the hydrothermal method, the obvious removal effect on fluorine in waste water is achieved, the purpose of treating waste with waste is achieved, and high-value utilization of the tungsten slag and the lithium slag is achieved.

The invention belongs to the technical field of preparation and application of nano materials, and relates to a preparation method and application of amino-functionalized cerium oxide nano enzyme, and the preparation method comprises the following steps: adding 3-aminophenylboronic acid into a cerous nitrate hexahydrate aqueous solution to obtain a mixed solution; dropwise adding a sodium hydroxide aqueous solution into the mixed solution, carrying out hydrothermal reaction, cooling after the reaction is finished, centrifuging, washing and drying to obtain milk white powder, namely the amino-functionalized cerium oxide nano-enzyme. The boron element is introduced in the preparation of the cerium oxide nano-enzyme, and the amino-functionalized cerium oxide nano-enzyme is prepared by adopting a simple one-step hydrothermal synthesis method, so that the nano-enzyme has good phosphatase-like activity, has high selectivity and sensitivity to LPS, and is short in detection time, high in sensitivity, low in detection limit, simple in preparation process and high in preparation efficiency; the product is good in quality, high in stability, environment-friendly and extremely wide in market prospect.

The invention belongs to the technical field of catalytic materials, particularly relates to an electrocatalytic anode oxygen evolution reaction catalyst based on an anion exchange membrane electrolytic cell, and particularly relates to a high-entropy oxide electrocatalyst and a preparation method thereof. The high-entropy oxide electrocatalyst is composed of five metal elements of Ni, Co, Fe, Mn and Al, is loaded on a foamed nickel substrate, has a nanosheet structure, is rich in oxygen vacancies on the surface, has excellent electrochemical catalysis performance and stability, and is suitable for electrocatalysis of an electrolytic water anode side in an alkaline environment. According to the preparation method of the high-entropy oxide electrocatalyst, foamed nickel is used as a substrate, salts of five metals of Ni, Co, Fe, Mn and Al which are equal in mole are subjected to hydrothermal synthesis to form a precursor, and then the high-entropy oxide electrocatalyst is prepared through self-etching, annealing oxidation and acid etching, and the high-entropy oxide electrocatalyst is easy and convenient to operate, good in repeatability, controllable in cost, excellent in performance and suitable for large-scale production.

The invention discloses a method for preparing a sodium-rich boundary-rich iron-based prussian blue analogue (FePBA) through one-step hydrothermal synthesis assisted by sodium thiosulfate. The method specifically comprises the following steps: preparing a solution A and a Na4Fe (I I) (CN) 6 solution; the molar ratio of ferrocyanide to Fe ions in the solution B is 3: 4. And preparing a solution B to react with ferrocyanide to form FePBA. Adding sodium citrate to form a sodium and citrate-rich environment, then adding ferric iron salt, and fully stirring to chelate the added Fe < 3 + > with the citrate; and adding sodium thiosulfate after the step. Preparing a PVP (Polyvinyl Pyrrolidone) solution to play roles in dispersing FePBA and reducing agglomeration, and taking the PVP solution as a solution C; slowly dropwise adding the solution A and the solution B into the solution C at a constant speed by using a rubber head dropper to finally obtain a precursor solution, carrying out hydrothermal reaction for 6 hours at 110 DEG C, carrying out suction filtration on the obtained precipitate, and drying to obtain a FePBA sample. According to the invention, the time required for synthesis is greatly shortened, and the traditional coprecipitation of more than 24 hours is improved into rapid hydrothermal reaction of 6 hours.

The invention provides a preparation method of nitrogen and phosphorus-doped carbon dots and application of the nitrogen and phosphorus-doped carbon dots in quercetin detection, the nitrogen and phosphorus-doped fluorescent carbon dots (N, P-CDs) are successfully constructed for the first time by adopting a hydrothermal synthesis method, and the carbon dots have emission peaks at 465 nm under the excitation wavelength of 325 nm and show green fluorescence under the irradiation of an ultraviolet lamp; quinine sulfate is used as a standard reference substance, and the quantum yield is 1301%; an N, P-CDs solution is used as a probe molecule, after quercetin is added, fluorescence quenching of N, P-CDs is induced, and the concentration of quercetin and the fluorescence intensity of N, P-CDs are linearly changed, so that the method can be used for quantitative detection of quercetin. The N, P-CDs preparation method provided by the invention is simple and rapid, the product property is stable and non-toxic, the detection sensitivity on the quercetin is high, and the N, P-CDs can be used for detecting the content of the quercetin in serum.

The invention discloses a silver vanadate photocatalytic material, a preparation method thereof and an illuminating lamp. The preparation method comprises the following steps: firstly, respectively dissolving NH4VO3 and AgNO3 in deionized water, uniformly mixing by magnetic stirring, adjusting the pH value of the solution, and then carrying out hydrothermal synthesis reaction to obtain the Ag3VO4 photocatalytic material. The Ag3VO4 photocatalytic material with controllable morphology, uniform particle size and good dispersity is prepared by adopting a synthesis strategy of a one-step hydrothermal method, the performance of the photocatalyst is optimized by regulating and controlling the pH value, the raw materials and the process are simple, the conditions are easy to control, the cost is low, the photocatalytic degradation rate of the catalyst to organic pollutants is high, and the method is suitable for industrial production. The stability of a crystal structure and catalytic activity can be kept under long-term illumination, and the functional application of a photocatalytic air purification technology can be realized by integrating with an illumination lamp.

The invention discloses a multi-metal layered hydroxide catalytic material and a preparation method and application thereof, and belongs to the technical field of catalytic materials.The preparation method of the multi-metal layered hydroxide catalytic material comprises the following steps that a one-pot solvothermal method is adopted, foamed nickel is soaked in a mixed solution for hydro-thermal synthesis, and the multi-metal layered hydroxide catalytic material is obtained; the multi-metal layered hydroxide catalytic material is prepared; wherein the mixed solution comprises a surfactant, a solvent and at least two of a nickel source, an iron source and a cobalt source. The CO2 desorption rate of the MEA solution is jointly improved through the synergistic effect of multiple metals and the # imgabs0 # acid site provided by the periphery of the metal hydroxide main layer. Under the condition that the desorption temperature (oil bath pan temperature) is 120 DEG C, the highest CO2 desorption rate of the FeCo (1 / 5) material with the best catalytic effect is increased to 7.68 mmol / min, and compared with 4.78 mmol / min under the blank condition, the desorption rate of the FeCo (1 / 5) material is increased by 60.7%, and the CO2 desorption rate is remarkably increased.

The invention relates to the technical field of nano molecular sieves, in particular to a nano FAU / EMT symbiotic molecular sieve and a preparation method thereof. The preparation method of the nano FAU / EMT symbiotic molecular sieve comprises the following steps: mixing and stirring an aluminum source, an alkali source and deionized water until the mixture is clear to form an alkaline aluminate solution, slowly adding a silicon source into the alkaline aluminate solution in batches, and continuously stirring to form uniform precursor gel; the precursor gel is subjected to aging treatment, hydrothermal crystallization treatment, centrifugal washing and drying, and the nano FAU / EMT symbiotic molecular sieve is obtained. The template-free one-step hydrothermal synthesis of the nano FAU / EMT symbiotic molecular sieve is realized. According to the method, use of an expensive and toxic organic template agent is avoided, and the preparation cost and the environmental pollution risk are remarkably reduced; meanwhile, one-step hydrothermal synthesis simplifies the technological process, improves the production efficiency and provides feasibility for industrial production.

The present invention relates to a method for preparing a DDR molecular sieve membrane. The method comprises preparing a seed suspension of Sigma-1 molecular sieve seeds obtained by ball milling, and coating the seed suspension onto a support. A synthesis solution is prepared by hydrothermal synthesis of a mixture of adamantaneamine, ethyleneamine, deionized water, and silica sol. The membrane is then calcined with ozone to obtain an activated DDR molecular sieve membrane. Compared to the prior art, the method employs a high-boiling-point ethyleneamine compound as a mineralizer, thereby eliminating the problem of toxic gas volatilization associated with the use of ethylenediamine as a mineralizer. Furthermore, the thickness of the prepared DDR molecular sieve membrane is significantly reduced.

The invention relates to the technical field of microfluidics, in particular to a carbon quantum dot hydrothermal synthesis system and method based on microfluidics thermal field equilibrium, which comprises a thermal field sensing module, an equilibrium analysis module, a thermal field coupling module, an equilibrium regulation and control module and a closed loop execution module, the thermal field sensing module is used for collecting array temperature on the surface of the micro-fluidic chip and fluid pressure data in a flow channel, and reconstructing three-dimensional temperature distribution in the micro-channel through a multi-physics field coupling algorithm to obtain a real-time thermal field state matrix. According to the invention, by constructing a multi-physical field coupling algorithm of a thermocouple array-flow resistance model-conjugate heat transfer equation, the three-dimensional temperature distribution of the fluid in the micro-channel can be inverted and reconstructed by using surface temperature and pressure data, so that a control system can pass through a chip matrix, and the temperature of the fluid in the micro-channel can be controlled. The radial temperature gradient and the axial thermal distortion in the fluid are directly sensed, the hysteresis and the error of sensor measurement are eliminated, and a real physical basis is provided for accurate temperature control.

The invention discloses a method for preparing a porous carbon / hydrotalcite-like compound adsorbent from fine coal gasification slag, which comprises the following steps: by taking the fine coal gasification slag as a raw material, sequentially carrying out alkali activation desiliconization and ion regulation, adding a pH regulator, stirring, and carrying out one-pot hydrothermal synthesis to obtain the porous carbon / hydrotalcite-like compound adsorbent. And carrying out solid-liquid separation and washing on the hydrothermal composition to obtain a solid phase, namely the porous carbon / hydrotalcite-like compound adsorbent. According to the invention, the pore structure of carbon is expanded while alkali activation desiliconization is carried out, so that the formation of porous carbon is ensured; the porous carbon / hydrotalcite-like compound adsorbent meets the requirement of forming a hydrotalcite-like compound with better crystallinity through ion regulation and control, provides an alkaline environment for synthesizing the hydrotalcite-like compound by adding a pH regulator, ensures the formation of the hydrotalcite-like compound through one-pot hydrothermal synthesis, and is obtained through solid-liquid separation and washing, the aggregation state in the hydrotalcite-like compound synthesis process is improved, and the stability and adsorption active sites of the composite adsorption material are increased.

Methods are provided for hydrothermal synthesis of b-oriented MFI zeolite. The method generally comprises forming a solution of precursors and reagents in effective ratios for a b-oriented MFI zeolite including a fluoride-containing mineralizer, and water-soluble oxidized disulfide oil. The solution is hydrothermally treated under effective conditions and for an effective time to synthesize b-oriented MFI zeolite.

The invention relates to micron-sized hexagonal flaky magnesium hydroxide with controllable particle size by using sodium hydroxide and bittern as raw materials and a preparation method thereof, belonging to the technical field of inorganic material preparation. The preparation method of the granularity-controllable micron-sized hexagonal flaky magnesium hydroxide with sodium hydroxide and bittern as raw materials comprises the following three steps: preparation of a magnesium hydroxide precursor, hydrothermal synthesis and post-treatment. According to the micron-sized hexagonal flaky magnesium hydroxide which takes sodium hydroxide and bittern as raw materials and is controllable in particle size, the particle size distribution tested by a laser particle analyzer is as follows: D10 is 0.96-1.18 mu m, D50 is 1.83-2.13 mu m, and D90 is 3.85-4.44 mu m.

The invention discloses a method for preparing a scale layer on a secondary side of a steam generator and a test sample piece on the secondary side of the steam generator. The method comprises the following steps: dissolving ferric salt, oxysalt, an acid compound and an organic solvent in deionized water to form a mixed aqueous solution; taking the mixed aqueous solution as a raw material, and depositing a scale layer precursor on a test sample on the secondary side of a steam generator by adopting a hydrothermal method; and heating the scale layer precursor in an inert gas atmosphere so as to form a simulated scale layer on the test sample. According to the method, preparation of the simulated scale layer is completed based on hydrothermal synthesis-high-temperature firing, the ultra-long period of preparing the simulated scale layer through high-temperature and high-pressure corrosion is avoided, rapid preparation of the steam generator secondary side sample sediment simulated scale layer is achieved, and the deposited scale layer growing closer to the actual operation environment can be simulated.

A preparation method for and the use of an aluminum hydroxide oxide nano-adjuvant based on calcium and silicon doping. The particle morphology of the AlOOH adjuvant is a 50-800 nm nano-particle, wherein silicon or calcium is doped in AlOOH crystal lattices, and the molar ratio of calcium or silicon to aluminum is 0.01-100:1. The preparation method comprises: synthesizing AlOOH by using an Al source, doping Ca or Si in a reaction solution by using a calcium source or a silicon source, precipitating Al(OH)3 and a dopant by adding an alkaline solution, and preparing a Ca- or Si-doped AlOOH adjuvant by means of a hydrothermal synthesis method. In a hepatitis B surface antigen and varicella-zoster virus glycoprotein E antigen model, the calcium- or silicon-doped AlOOH nano-adjuvant can simultaneously induce efficient humoral immunity and cellular immunity by means of in-vivo experiment verification of mice.

Methods are provided for hydrothermal synthesis of porous crystalline materials. The method generally comprises forming a solution of precursors and reagents in effective ratios for a porous crystalline material including a fluoride-containing mineralizer, and water-soluble oxidized disulfide oil. The solution is hydrothermally treated under effective conditions and for an effective time to synthesize porous crystalline materials.

The invention relates to the technical field of preparation of catalysts, in particular to a solar-driven CO2 capturing and cracking catalyst, a preparation method and application, and the preparation method comprises the following steps: S1, mixing a solid metal-based carrier precursor with deionized water, performing hydrothermal synthesis in a hydrothermal reaction kettle at 180-220 DEG C for 12-14 hours, and calcining at 300-600 DEG C for 2-4 hours to obtain a porous carrier; s2, co-impregnating a porous carrier with a metal salt solution and the modified impregnation liquid, drying, and calcining in a nitrogen atmosphere at 300-600 DEG C for 2-6 hours to obtain an active component supported catalyst precursor; and S3, mixing a reaction medium and a modified doping solution, compounding with the active component loaded catalyst precursor obtained in the step S2, and drying to obtain the solar-driven CO2 capture cracking catalyst. Through the one-step hydrothermal synthesis and co-impregnation process, the preparation process is simplified, the traditional complex process of separation after CO2 capture is omitted, the comprehensive cost is reduced by more than 30%, and the traditional high-energy-consumption carbon dioxide pressure swing adsorption and temperature swing adsorption technology is completely eliminated.

The invention relates to the technical field of electro-catalytic materials, in particular to a preparation method of a NiFe LDH / NiFeO / NF composite catalyst. The method comprises the following steps: carrying out acetic acid solution pretreatment on a foamed nickel substrate; growing a nickel-iron precursor on the pretreated foamed nickel through the first hydrothermal reaction, and treating to obtain NiFeO / NF; and growing a nickel-iron layered double hydroxide nanosheet on the surface of the NiFeO / NF through a second hydrothermal reaction to obtain the NiFe LDH / NiFeO / NF composite catalyst. According to the preparation method of the NiFe LDH / NiFeO / NF composite catalyst provided by the invention, a NiFeO / NF matrix is prepared by a hydrothermal synthesis method, after air heat treatment, a NiFe layered double hydroxide nanosheet with a smaller size is synthesized on the surface of NiFeO / NF by adopting a secondary hydrothermal process, and finally the NiFe LDH / NiFeO / NF composite catalyst is obtained.

The invention discloses a preparation method of cellulose micron sheet powder and a high-haze transparent film thereof, which comprises the following steps: S1, crushing bamboo pulp foil to obtain a cellulose raw material; s2, placing in a sulfuric acid solution, stirring in an oil bath for hydrolysis, adding water after reaction, taking out, and placing in a polytetrafluoroethylene hydrothermal synthesis reaction kettle for auxiliary reaction to obtain a milk white suspension; s3, centrifuging and dialyzing the milk white suspension until the pH is nearly neutral; s4, performing ultrasonic treatment on a product in S3 by adopting an ultrasonic cell crusher, and performing freeze drying to obtain powdery cellulose micron sheets; according to the invention, through reasonable optimization of acidolysis and hydrothermal process parameters, the powdery cellulose micron sheet with uniform thickness and no irreversible keratinization defect is obtained, has excellent redispersibility after rehydration, can be compounded with polyvinyl alcohol to form a high-haze transparent film, and overcomes the defect that in the subsequent drying process of sulfuric acid hydrolysis of micro-nano cellulose, the film is not easy to form, and the film is not easy to form. The problems of irreversible agglomeration and poor rehydration redispersibility caused by hydrogen bond induction are solved.

The invention belongs to the technical field of energy storage materials, and particularly discloses preparation and application of a high-performance asphalt-based porous carbon material. The method comprises the following steps: pre-treating asphalt; carrying out hydrothermal synthesis on microcrystalline cellulose and phytic acid to obtain cellulose ester; the preparation method comprises the following steps: compounding humic acid, hectorite powder and cellulose ester, and freeze-drying to obtain a compound additive; carrying out microwave-hydrothermal reaction on the pretreated asphalt and a compound additive to form a precursor; and activating the precursor, carbonate and phosphate in a multi-section gradient atmosphere, and finally washing and drying to obtain the porous carbon material. According to the method, strong base etching is replaced by synergistic pore-forming and atmosphere activation of the composite additive, so that green controllable pore expansion and uniform doping of heteroatoms are realized; and a graded pore channel structure is accurately constructed through multi-section carbonization. The obtained material has a three-dimensional interpenetrating network, a high specific surface area and excellent conductivity, can effectively buffer ion embedding stress, remarkably improve electrochemical stability and inhibit volume expansion, and is suitable for lithium and sodium ion battery negative electrodes and supercapacitor electrodes.

The invention relates to the technical field of catalysts, and particularly discloses a composite catalyst for preparing acrolein through catalytic oxidation of propylene and a preparation method of the composite catalyst, the composite catalyst comprises an active component I and an active component II, and the use mass ratio of the active component I to the active component II is 1: (1-19); the active component I is bismuth tungstate microspheres obtained by a hydrothermal synthesis method, and the general formula of the active component I is BiaW1Ox; the active component II is a multi-metal oxide obtained by a coprecipitation method, and the general formula of the active component II is Mo < 12 > Bi Co < c > Ni < d > Fe < e > A < f > B < g > O < y >; the bismuth tungstate microspheres obtained by a hydrothermal synthesis method and the multi-metal oxide obtained by a coprecipitation method are mixed to obtain the composite catalyst, so that the bismuth tungstate microspheres with microsphere structures can be used as active phases of reaction, and the specific surface area and the pore volume of the composite catalyst can be increased; the catalyst is suitable for a reaction for preparing acrolein through propylene catalytic oxidation under high load.

The invention discloses tetragonal system germanium dioxide and a hydrothermal synthesis method thereof. According to the method, hexagonal crystal system germanium dioxide is taken as a raw material, a hydrothermal reaction is carried out in an acidic aqueous solution, and efficient conversion from a hexagonal crystal system to a tetragonal crystal system is realized by controlling the reaction temperature to be 120-240 DEG C, the reaction time to be 24-48 hours and the pH value to be 1-3. According to the preferable scheme, the raw materials are subjected to calcination pretreatment at the temperature of 500-600 DEG C, the yield of the tetragonal crystal phase can be remarkably increased, and the synthesis temperature can be reduced to 120 DEG C. According to the invention, stable synthesis of tetragonal system germanium dioxide is realized for the first time under the mild condition of 240 DEG C and below, and the technical problem that high-temperature transformation at 1000 DEG C or above is needed in the traditional method is solved. The tetragonal crystal system germanium dioxide prepared by the method is of a regular polyhedral structure, has the particle size of 400-500nm, and can be used as a high-efficiency catalyst for polyester synthesis. The process is energy-saving and environment-friendly, the total utilization rate of the raw materials is increased by recycling the waste liquid, and the process has remarkable industrial application value.

The invention provides a bismuth ferrite-graphite phase carbon nitride photocatalyst and a preparation method and application thereof, and relates to the technical field of photocatalysis, the preparation method comprises the following steps: dissolving a bismuth source and an iron source in a solvent, mixing with a mineralizing agent, and carrying out a hydrothermal synthesis reaction to obtain bismuth ferrite; performing first roasting treatment on the nitrogen-containing organic matter precursor to obtain graphite-phase carbon nitride; and mixing bismuth ferrite and graphite phase carbon nitride, and carrying out grinding treatment and second roasting treatment to obtain the bismuth ferrite-graphite phase carbon nitride photocatalyst. According to the preparation method, bismuth ferrite and graphite-phase carbon nitride which are prepared respectively are compounded, a Z-type heterojunction can be constructed at an interface of the bismuth ferrite and the graphite-phase carbon nitride, an internal electric field is formed, so that photo-induced electrons and holes are efficiently separated, compounding of the photo-induced electrons and the holes is effectively inhibited, and finally the oxidation-reduction capacity of the material is remarkably enhanced; therefore, the photocatalyst shows excellent photocatalytic performance, high selectivity and good cycle stability.

The application relates to a preparation method of an ordered defective indium cluster framework porous material for electrocatalytic reduction of carbon dioxide to urea, and belongs to the technical equipment field of ordered defective metal organic framework synthesis, in particular to a preparation method of an ordered defective indium cluster framework material for electrocatalytic reduction of CO2 to urea, which comprises a preparation method of five steps; through the above design, the ordered defective indium cluster framework porous material is synthesized by adopting a hydrothermal synthesis mode, taking indium trifluoromethyl sulfonate as a metal source and a square fan of in-situ self-assembly; the preparation method of the application can obtain the ordered defective indium cluster framework porous material, the obtained product indium cluster framework porous material has uniform micron-level size and excellent stability, the method used in the application is simple in operation, the obtained catalyst defect order exhibits excellent selectivity in electrocatalytic reduction of carbon dioxide to urea at a lower overpotential, which is difficult to realize by the existing metal organic framework-based catalyst.

The invention relates to the field of catalytic materials, and provides a metal oxide composite material for preparing ethane through photocatalytic methane conversion and a preparation method of the metal oxide composite material. The material is a ternary composite functional material with a multi-stage structure and multi-scale characteristics, and comprises a micron-scale porous alumina carrier skeleton which is prepared by a freeze drying method and has directional through columnar pore channels, CeO2 nanorods which grow in the pore channels in situ, and an anatase type TiO2 shell layer which coats the surfaces of the CeO2 nanorods. The composite material forms a CeO2-TiO2 core-shell structure and a TiO2 thin layer on the inner wall of a pore channel, and has excellent photocatalytic activity and thermal shock resistance. The activity attenuation rate does not exceed 10% after irradiation of a light source with the wavelength of 365 nm and 20 times of thermal cycles at the temperature of 25-800 DEG C. The preparation method comprises the steps of freeze-drying forming and heat treatment of an aluminum oxide framework, in-situ hydrothermal synthesis of CeO2 nanorods and hydrolytic deposition and calcination of a TiO2 shell layer, the process is simple and convenient, the repeatability is high, and the method is suitable for efficient and stable photocatalysis application.