777 results about "Hydrogen atmosphere" patented technology

The invention belongs to the field of waste artificial graphite regeneration, and particularly relates to a waste artificial graphite regeneration method, a regenerated material and application thereof, the regeneration method comprises the following steps: carrying out normal pressure liquid phase modification on waste artificial graphite in an organic acid solution in advance, and then putting the modified waste artificial graphite in an inorganic acid solution for positive pressure liquid phase modification to prepare a modified material; mixing the modified material with a Mn source, a metal N source, a first carbon source and a binder to obtain a mixture, then performing heat treatment on the mixture in a hydrogen-containing atmosphere, and then performing negative-pressure annealing treatment to obtain a heat-treated material; the metal N source comprises a compound of at least one of iron, cobalt and nickel; and mixing the heat-treated material with lithium salt and a second carbon source, and carrying out roasting treatment to obtain the graphite regenerated material. The regeneration method disclosed by the invention is particularly suitable for repairing the artificial graphite waste which is difficult to treat, so that the artificial graphite waste can be repaired to obtain a material with excellent capacity, long circulation and particularly low-temperature stability.

This invention discloses a method for preparing a CuZnAlGa-based layered double hydroxide (TLH)-derived catalyst for methanol production from carbon dioxide-rich syngas. Using Cu, Zn, Al, and Ga metal salts as precursors, Na₂CO₃ and NaOH as precipitants, and a mixed alcohol-water solution as an auxiliary solvent, co-precipitation is performed under controlled temperature and pH to obtain a LDH-like catalyst precursor. After high-temperature calcination and in-situ reduction in a hydrogen atmosphere, a layered framework structure of Cu nanoparticles immobilized by oxides is obtained. The LDH-like structure provides lattice confinement, preventing Cu particle aggregation, and the interaction between Cu and the oxides enhances the catalyst surface's adsorption capacity for CO and CO₂, thereby improving the activity and stability of methanol production from carbon dioxide-rich syngas.

The invention discloses a high-entropy alloy system high-temperature brazing filler metal and a preparation method and application thereof, and relates to the technical field of welding materials.The preparation method comprises the following steps that iron powder, cobalt powder, nickel powder, copper powder and molybdenum powder are weighed and evenly mixed, and mixed metal powder is obtained; the mixed metal powder is put into a first ball milling tank, argon is introduced, ball milling is conducted for at least 15 h, and alloyed powder is obtained; the alloyed powder is put into a mold and sintered in the hydrogen atmosphere at the temperature of 1000-1200 DEG C, and a sintered blank is obtained; the sintered briquette is crushed into particles, the particles are put into a second ball milling tank, ball milling is conducted for at least 20 h in the argon atmosphere, and high-entropy alloy powder is obtained; and weighing the high-entropy alloy powder, borax and polyvinyl alcohol, and uniformly mixing to obtain the high-entropy alloy system high-temperature brazing filler metal. The prepared high-entropy alloy system high-temperature brazing filler metal has the advantages of being good in component uniformity, high in performance stability and excellent in wettability and filling performance, and the welding quality of a brazed joint can be effectively guaranteed.

The invention discloses an annular furnace heat-resistant supporting forged chassis and an additive manufacturing process and a fixing device thereof, and belongs to the technical field of plating of metal materials, and the annular furnace heat-resistant supporting forged chassis comprises the steps that heat-resistant alloy steel base metal with specific components is prepared; carrying out laser texturing and nickel-based alloy bottom layer pretreatment on the surface of the steel plate; performing laser cladding on high-silicon high-temperature alloy powder containing niobium and rare earth elements to form a functional cladding layer, and performing gradient cladding on the edge of the atmosphere guide hole; and finally, carrying out heat treatment and assembling with a fan-shaped refractory brick fixing device. A composite oxide film and a multi-scale strengthening system are constructed, hydrogen resistance and brittleness resistance are effectively achieved, interface thermal stress is relieved, cracking and stripping of a cladding layer are avoided, a fixing device adapts to thermal expansion, the atmosphere is dredged, and the annealing uniformity of a steel coil is improved; the problems of creep deformation, hydrogen embrittlement, cladding layer stripping and thermal stress cracking of a traditional supporting component under the conditions of high temperature, heavy load and nitrogen and hydrogen atmosphere are solved.

The invention discloses a method for preparing cyclohexylamine based on reductive amination of cyclohexanone, and belongs to the technical field of fine chemical engineering. The preparation method comprises the following steps: adding a reactant cyclohexanone into a reaction kettle containing a certain amount of solvent, ammonia water and hydrogen atmosphere, and carrying out reductive amination reaction in the presence of a catalyst to obtain cyclohexylamine. The catalyst is CoyAl-LDHs loaded with metal active components, the CoyAl-LDHs are layered cobalt-aluminum bimetal hydroxides, and cobalt ions and precious metal ions in laminates are subjected to spontaneous oxidation-reduction reaction, so that the precious metal ions can be efficiently reduced into active metal nanoparticles. The layered cobalt-aluminum double-metal hydroxide not only has abundant surface acid-base sites, but also has high dispersity of loaded metal nanoparticles. The catalyst preparation and reductive amination reaction conditions are mild, the yield is high, the reaction system is simple and easy to separate, and the method is suitable for industrial production of cyclohexylamine.

This invention belongs to the field of high-value utilization technology of biomass resources, and discloses a method for catalyzing the depolymerization of lignin into phenolic compounds using a RuNiZn / Nb2O5 catalyst. The method includes: uniformly mixing the RuNiZn / Nb2O5 catalyst, lignin-containing biomass feedstock, and water; stirring under hydrogen atmosphere to carry out the depolymerization reaction; after the reaction, cooling to room temperature and performing solid-liquid separation; evaporating the solvent to obtain the hydrogenated depolymerization product containing monophenols. In this invention, the RuNiZn / Nb2O5 catalyst employs a technique of replacing precious metals with various non-precious metals, which improves the catalyst's reactivity and reduces the amount of precious metals used. This increases the yield of lignin depolymerization products, provides milder depolymerization reaction conditions, and ultimately significantly reduces the catalyst preparation cost and the energy cost of the lignin depolymerization process.

The invention relates to a platinum-based catalyst for preferential catalytic oxidation of carbon monoxide in a hydrogen-rich atmosphere and preparation and application thereof, the composition of the catalyst is Pt / M1-M2Ox, Pt is an active component, and the content of Pt is 0.10-5.00 wt.%; m1 is an auxiliary agent and is selected from one or more of Fe, Co, Ni, Cu and Zn oxides, and the mass fraction of M1 in the catalyst is 0.01-5.00 wt.%; the carrier is M2Ox oxide, and M2 is one of Zr, Ti, Al and Si. Compared with the prior art, the Pt / M1-M2Ox catalyst has the advantages that the chemical state of the noble metal is adjusted by the aid of the aid M1, and the Pt / M1-M2Ox catalyst has excellent CO-PROX reaction activity and stability. The preparation method has the characteristics of simplicity in operation, high stability, good repeatability and the like.

The invention discloses a preparation method of chloroprocaine hydrochloride, and belongs to the technical field of chloroprocaine hydrochloride synthesis. Comprising the following steps: (1) preparing 4-amino-2-chlorobenzoic acid: dissolving 2-chloro-4-nitrobenzoic acid in a solvent, and uniformly stirring; adding a ruthenium catalyst Ru / SNC into the system, and carrying out heat preservation reaction in a hydrogen atmosphere; the 4-amino-2-chlorobenzoic acid is obtained through a reaction; (2) preparation of chloroprocaine hydrochloride: dissolving 4-amino-2-chlorobenzoic acid, 2-chloroethyl diethylamine and a solid base catalyst K / r-GO in a reaction solvent, and carrying out an esterification reaction; the 2-(diethylamino)-2-chlorine-4-nitrobenzoic acid ethyl ester is obtained; and then salifying and drying to obtain the chloroprocaine hydrochloride. The catalyst provided by the invention realizes efficient catalytic reaction at lower temperature and pressure, can be recycled for dozens of times, and is suitable for large-scale industrial production.

The invention provides a preparation method of a composite substrate for semiconductor device production, which comprises the following steps: putting raw material carbon into a reaction chamber in a hydrogen atmosphere, vacuumizing the reaction chamber, heating to 1000-1500 DEG C, such as 1000 DEG C, 1200 DEG C and 1500 DEG C, preserving heat for 1-3 hours, cooling and cleaning to obtain a carbon substrate; grinding and mixing a tantalum source, a tantalum fluoride and a fluxing agent to obtain coating powder; transferring the coating powder into a reaction chamber with a pulsed electric field, carrying out pulsed electric field assisted vapor deposition, and cooling to obtain a tantalum carbide pre-coating material with directionally arranged crystal orientations; and transferring the tantalum carbide pre-coating material into a high-temperature sintering furnace, and heating the tantalum carbide pre-coating material in an inert atmosphere at 1800-2400 DEG C for 0.5-6 hours to obtain the composite substrate which is used for producing a semiconductor device. Through directional arrangement of crystal orientations, the tantalum carbide coating achieves higher electrical conductivity and thermal conductivity.

The invention belongs to a preparation method of a chemical intermediate, and particularly relates to a preparation method of dimethyl 1, 4-cyclohexanedicarboxylate, which comprises the following steps: carrying out hydrogenation reaction on dimethyl p-toluene in a solvent in a hydrogen atmosphere under the catalysis of a cerium dioxide loaded ruthenium monometal catalyst to obtain the dimethyl 1, 4-cyclohexanedicarboxylate, the invention discloses a method for preparing dimethyl 1, 4-cyclohexanedicarboxylate from dimethyl terephthalate through hydrogenation, which comprises the following steps: under the catalysis of a ruthenium-containing catalyst taking cerium dioxide as a carrier, carrying out hydrogenation reaction on dimethyl terephthalate in a solvent in a hydrogen atmosphere to obtain dimethyl 1, 4-cyclohexanedicarboxylate, and separating the dimethyl 1, 4-cyclohexanedicarboxylate from dimethyl terephthalate to obtain dimethyl 1, 4-cyclohexanedicarboxylate. And after the reaction is completed, the high-purity dimethyl 1, 4-cyclohexanedicarboxylate can be obtained only by filtering out the catalyst and concentrating to remove the solvent, and the operation is simple and convenient.

The invention belongs to the technical field of catalyst preparation, and particularly relates to a preparation method of a high-dispersion platinum group noble metal-based catalyst, which comprises the following steps: preparing a porous rod-like cobaltosic oxide carrier material, cleaning with deionized water, drying, and roasting for 4-8 hours; dissolving chloroplatinic acid or platinum chloride in deionized water to form a noble metal solution; soaking the treated cobaltosic oxide carrier in a noble metal solution, taking out the carrier from the solution after soaking is completed, filtering, cleaning, drying, and roasting for 4-6 hours in an inert gas atmosphere; and keeping the temperature and reducing for 2-4 hours in a hydrogen atmosphere. When the porous rodlike cobaltosic oxide carrier material is prepared, firstly, a cobalt chloride solution is poured into the lower part of the double-layer cavity for stirring, a urea solution drips into the cavity through a spray head in the stirring process, a stirring barrel is turned over after stirring is completed, the stirred solution flows out and is filtered, the cobalt chloride solution and the urea solution are continuously added into the double-layer cavity for stirring and mixing, and the porous rodlike cobaltosic oxide carrier material is prepared. Therefore, the porous rod-like cobalt oxide solvent material is efficiently prepared.

The invention belongs to the technical field of chemical catalysts, and particularly discloses a high-humidity-tolerance Pt / SSZ-13 molecular sieve catalyst and a preparation method and application thereof.The preparation method comprises the following steps that S1, a platinum metal precursor solution is prepared, specifically, platinum particles are added into a solvent according to a certain proportion, and the platinum metal precursor solution is obtained through dispersion and dissolution; s2, dipping and loading: dipping an SSZ-13 molecular sieve carrier into the platinum metal precursor solution obtained in S1 by adopting a dipping method, and uniformly stirring; s3, drying: drying at the temperature of 60-120 DEG C for 3-12 hours; s4, roasting: roasting for 1-10 hours at the temperature of 600-800 DEG C in an air atmosphere; and S5, reduction: reducing at 100-300 DEG C in a hydrogen atmosphere for 1-3 hours to obtain the Pt / SSZ-13 molecular sieve catalyst. According to the high-humidity-tolerance Pt / SSZ-13 molecular sieve catalyst as well as the preparation method and the application thereof, the Pt / SSZ-13 catalyst is obtained by utilizing a small-hole molecular sieve carrier and optimizing Pt loading and a preparation process, the high-humidity-tolerance and stability are realized, and the problem that an existing catalyst is insufficient in activity under the conditions of room temperature and high humidity is solved.

The invention discloses a perovskite / crystalline silicon laminated solar cell, a preparation method thereof and a photovoltaic module. The perovskite / crystalline silicon laminated solar cell provided by the invention comprises a perovskite top cell, a crystalline silicon bottom cell and a composite layer used for connecting the perovskite top cell and the crystalline silicon bottom cell, the perovskite top cell comprises a composite hole transport layer, the composite hole transport layer comprises a first hole transport layer and a second hole transport layer, and the first hole transport layer is in contact with the composite layer; the first hole transport layer is obtained by sputtering a nickel oxide target material by introducing H2 in an oxygen-free sputtering atmosphere, and the second hole transport layer is obtained by sputtering the nickel oxide target material in a hydrogen-free atmosphere. According to the perovskite / crystalline silicon laminated solar cell provided by the invention, the composite hole transport layer can realize better contact matching with the middle composite layer, better charge extraction and collection are carried out on the perovskite light absorption layer, and meanwhile, the perovskite / crystalline silicon laminated solar cell has better conductivity.

The invention relates to the technical field of catalysts, and particularly discloses a Cu-based catalyst for preparing 1, 2-pentanediol and a preparation process of the 1, 2-pentanediol. The Cu-based catalyst used for preparing 1, 2-pentanediol comprises 6-72% of a copper salt, 20-70% of a carrier, 4-12% of a transition metal oxide and 4-12% of a polymeric nitrogen-containing organic ligand, and the polymeric nitrogen-containing organic ligand is polypyrrole or polyaniline. The preparation process of the 1, 2-pentanediol comprises the following steps: mixing furfural, isopropanol and a Cu-based catalyst for preparing the 1, 2-pentanediol, adding the mixture into a high-pressure reaction kettle, and reacting for 10-14 hours in a hydrogen atmosphere of 2.8-3.2 MPa and at the temperature of 145-155 DEG C under continuous stirring to obtain the 1, 2-pentanediol. According to the Cu-based catalyst, the combination effect between the carrier and Cu can be enhanced, so that active Cu loaded on the carrier is more stable in the reaction process, and the catalytic performance of the Cu-based catalyst is improved.

The invention belongs to the technical field of fluorine chemical industry, and relates to preparation and application of a hydrodechlorination catalyst, a preparation method comprises the following steps: dipping a palladium source and a copper source on an activated carbon carrier, drying, and sequentially carrying out heating pretreatment in an inert atmosphere, reduction treatment in a hydrogen atmosphere and passivation treatment in an air atmosphere; in the obtained catalyst, the loading capacity of palladium on the activated carbon carrier is 0.5-0.1 wt%, and the loading capacity of copper on the activated carbon carrier is 5-0.1 wt%. Compared with the prior art, the preparation method has the advantages of low metal loading capacity, low reaction temperature, controllable product selectivity and the like, and the granular active carbon is adopted, so that the influence of active carbon extrusion molding and molding auxiliaries on preparation and performance of the catalyst can be avoided. Meanwhile, the catalyst can be used for the hydrodechlorination reaction of CFC-113, the problems of fast deactivation, poor stability and high use cost of the conventional catalyst can be solved, and an effective way is provided for converting fluorochloroalkane into fluorine-containing olefin.

The invention discloses a production method of HMDA (4, 4 '-MDA), which comprises a process of pretreating a catalyst before a catalytic hydrogenation reaction of 4, 4'-MDA, the pretreatment method of the catalyst comprises the following steps: mixing the catalyst, a solvent and a heavy component-reaction regulator, treating for a period of time in a high-temperature hydrogen atmosphere, filtering out the catalyst after the treatment is finished, and carrying out a subsequent catalytic hydrogenation reaction; the heavy component, namely the trans regulator, is cis-1, 4-di (aminomethyl) cyclohexane; preferably, the addition amount of the heavy component, namely the anti-reaction regulator, is 0.1-15 wt% of the mass of the catalyst. The yield of the H12MDA exceeds 95%, the trans-trans isomer content is 13-15%, no heavy components are generated, the unit consumption of the raw materials is greatly reduced, and the catalyst is not inactivated after being used for 60 batches.

The invention relates to a polysaccharide coated-hydrogen pre-sintered dispersed graphene copper composite material and a preparation method thereof, and the preparation method comprises the following steps: mixing first copper powder with a coating solution, and removing a solvent to obtain coated copper powder; sintering the coated copper powder in a hydrogen atmosphere for the first time to obtain graphene coated copper powder; second copper powder and the graphene-coated copper powder are mixed, and the graphene-copper composite material is obtained through second sintering and forming; the solute of the coating solution comprises polysaccharide and an organic auxiliary agent, and the number of carbon atoms of the polysaccharide is greater than or equal to 10. According to the preparation method, through molecular-level coating of the polysaccharide and the organic additive, the coating layer is converted into a few-layer graphene or high-quality carbon layer which is uniformly attached to the surface of the copper powder in situ during first sintering, so that the high-quality graphene copper composite material is obtained.

The invention discloses a preparation method of nano tungsten-nickel-iron composite powder, which comprises the following steps: 1, dissolving ammonium metatungstate, nickel chloride hexahydrate and ferric chloride hexahydrate in water, and stirring to obtain a solution; step 2, atomizing the solution and spraying the atomized solution into liquid nitrogen for pre-freezing to obtain frozen particles; 3, freeze-drying the frozen particles to obtain precursor composite powder; and 4, the precursor composite powder is subjected to roasting and reduction in the hydrogen atmosphere in sequence, and the nano tungsten-nickel-iron composite powder is obtained. According to the preparation method, frozen particles containing tungsten, nickel and iron are obtained through pre-freezing, then solid ice of the frozen particles is directly sublimated into gas to be separated through a freeze-drying process, nanoscale precursor composite powder is obtained, and the nano tungsten-nickel-iron composite powder is prepared through roasting and reduction in the hydrogen atmosphere. The method is suitable for the technical field of powder preparation engineering.

The invention provides a method for synthesizing diol from glucose, which comprises the following steps: adding glucose, a catalyst and deionized water into a reaction kettle, and carrying out heating catalytic reaction in a hydrogen atmosphere to obtain diol, the main product of which is butanediol; wherein the catalyst is a Pd-WO3 composite nano catalyst loaded by a carrier. The catalyst can be used for preparing diol, the novel catalyst is formed by combining the carrier and the specific composite nano-catalyst, the combination can selectively catalyze glucose to be converted into 1, 2-butanediol under mild conditions, and compared with an existing metal catalyst, the catalyst has higher catalytic efficiency and conversion rate; meanwhile, the catalyst is stable in activity and longer in service life, so that the production cost is reduced, and the production efficiency is improved; in addition, the preparation process of the catalyst is simple, the catalyst can keep excellent catalytic activity in the recycling process, and compared with an existing catalyst preparation process, the preparation method has higher production efficiency and economic benefits.

The present invention relates to a preparation process of a high-density tungsten-copper alloy. The preparation process comprises: mixing oxide powder of copper having a certain proportion with oxide powder of tungsten in a dual-power mixer, performing crushing and activation treatment on the mixed powder in a high-speed crusher, and then reducing in a hydrogen atmosphere to obtain the nano tungsten-copper composite powder; and carrying out sheathing, degassing, and hot isostatic pressing treatment on the nano tungsten-copper composite powder, carrying out thermoplastic processing, and then carrying out annealing treatment to obtain the high-density tungsten-copper alloy. The process of the present invention is simple and controllable, has high operability, and is easy to industrialize; the phenomena of component segregation caused by preparation of the tungsten-copper alloy by an infiltration method, and uneven crystal grain size caused by particle aggregation and growth are avoided; and the proportion of the two-phase components can be accurately regulated, so that the tungsten-copper alloy with a tungsten content of 5%-95% can be prepared. The density (relative density) of the prepared tungsten-copper alloy reaches 99.6% or above; the oxygen content is lower than 40 ppm; the alloy has a uniform structure; the crystal grains are fine; and the present invention has wide application prospects and popularization value.

The invention provides a method for preparing alpha-olefin from a triglyceride compound, and relates to the technical field of organic synthesis. According to the method provided by the invention, in a solvent environment, a hydrogen-containing atmosphere and at 50-300 DEG C, a triglyceride compound I reacts under the catalysis of a NiCu bimetallic catalyst to generate alpha-olefin II-1, alpha-olefin II-2 and alpha-olefin II-3. According to the method provided by the invention, the triglyceride compound is adopted as a reaction substrate, the alpha-olefin compound can be efficiently synthesized, the reaction is green and efficient, the atom utilization rate is high, and no pollution is caused.

The present invention relates to a preparation method and application of a catalyst for catalyzing the production of mesitylene from trimethylbenzene. The method comprises the following steps: firstly preparing a multi-level pore Hβ zeolite molecular sieve, then mixing the multi-level pore Hβ zeolite molecular sieve with a hydrogen-type mordenite molecular sieve and a binder, adding a nitric acid solution and water, extruding the zeolite molecular sieve into strips, drying the strips and then calcining the strips at 500-750°C to obtain an unmodified catalyst I; performing impregnation modification on the unmodified catalyst I, then drying and calcining the strips to obtain a modified catalyst; and reducing the modified catalyst in a hydrogen atmosphere at 0.3-1MPa and 350-450°C to obtain a catalyst for isomerization of trimethylbenzene to mesitylene. The present invention utilizes a multi-level pore Hβ zeolite molecular sieve and a hydrogen-type mordenite molecular sieve to form a composite molecular sieve catalyst, then adding rare earth metals, Group VIII, Group IIIB and Group IVB as modifying elements, and reducing the catalyst with hydrogen to improve the selectivity and thermal stability of the catalyst, while increasing the life of the catalyst and improving the economic efficiency of the device.

The invention relates to the technical field of diamond color center quantum light sources, in particular to a method for preparing a diamond color center in a positioning mode, and the method comprises the following steps that a single-face polished sapphire sheet serves as a substrate, and a microwave plasma chemical vapor deposition method is adopted for preparing a single crystal diamond with a (001) surface; preparing a metal layer on the surface of the monocrystal diamond by adopting a physical vapor deposition method, and dehumidifying and self-assembling to form balls; etching the surface of the monocrystal diamond (001) at a high temperature in a hydrogen atmosphere to form a conical pit structure with a different surface; and selectively growing a diamond color center in the cone pit by adopting a chemical vapor deposition method. Aiming at the problems that the existing ion implantation technology for positioning and preparing the diamond color center is difficult to realize nanoscale accurate control and high in cost, a foundation is laid for the integration and low-cost preparation of the high-purity and high-brightness diamond single photon source.

The invention provides a room-temperature hydrogen sensor as well as a preparation method and application thereof, and belongs to the technical field of hydrogen sensors. According to the invention, sulfur-metal chemical bond combination between a thiol end group of a dithiol organic molecule and metal is utilized, a layer of porous thiol self-assembled monomolecular layer film is constructed between a palladium hydrogen sensitive layer and a first electrode of a substrate, and the palladium sensitive layer is suspended on the self-assembled monomolecular layer, so that the palladium sensitive layer is fully exposed in a hydrogen atmosphere; the adsorption / desorption dynamic performance of the palladium membrane in the hydrogen response process is greatly improved, so that the response speed of the sensitivity of the sensor is remarkably improved. Besides, the carbon chain structure of the self-assembled monomolecular layer has excellent mechanical toughness and lubricity, interface stress generated in the hydrogen absorption expansion process of the palladium sensitive layer can be effectively relieved, the stability of the sensor is greatly improved, and the service life of the sensor is greatly prolonged. The sensor prepared by the invention can detect low-concentration (1ppm) hydrogen at room temperature, and can stably work for more than 10 years.

The invention discloses a Cu-based catalyst for carbon dioxide catalytic conversion and a preparation method thereof.The preparation method comprises the following steps that S1, a precursor solution providing a molybdenum source is prepared, the precursor solution and organic matter are mixed and stirred to be uniform, and a mixture is obtained; s2, drying the mixture, and performing high-temperature roasting treatment in a pure hydrogen atmosphere to obtain a Mo2C carrier; s3, dispersing the Mo2C carrier into pure water, dropwise adding a metal cation saline solution providing a copper source and a cerium source, adjusting the pH to be alkaline, stirring, aging, and filtering to obtain a precipitate; and S4, drying the precipitate in vacuum, and calcining in a pure hydrogen atmosphere to obtain the Cu-CeO2 / Mo2C catalyst. The Cu-based catalyst for the catalytic conversion of the carbon dioxide, which is high in CO2 conversion rate and CO selectivity, can be prepared, and technical support can be provided for the catalytic conversion of the CO2.

The invention discloses a rapidly sintered rhenium plate and a preparation method thereof, and relates to the field of powder metallurgy. The preparation method comprises the following steps: putting a mold filled with rhenium powder into spark plasma sintering equipment, vacuumizing, introducing hydrogen-containing mixed gas, carrying out a gradient pressurization-pulse sintering process, heating the rhenium powder to a target temperature at a rate of 80-200 DEG C / min, carrying out heat preservation, synchronously applying axial pressure, controlling the pressure to be 8-12 Mpa when the temperature is less than 1000 DEG C, controlling the pressure to be greater than or equal to 15 Mpa when the temperature is greater than or equal to 1000 DEG C, and carrying out sintering for 2-3 hours; and cooling, demolding, reducing and annealing in a hydrogen atmosphere, and grinding to obtain the rhenium plate. Rapid sintering densification of pure rhenium is achieved through the spark plasma sintering technology, the temperature rising time is greatly shortened, step pressure rising is carried out before the nucleation stage of heating sintering, it is avoided that moving filling of rhenium powder is hindered by high pressure at the low temperature, size homogenization is promoted, and the prepared rhenium plate is good in uniformity and high in density and purity; and the oxygen content is low.

The invention discloses lithium borohydride and a preparation method thereof, and belongs to the technical field of hydrogen storage material preparation. The preparation method provided by the invention comprises the following steps: in a hydrogen atmosphere of 50bar, mixing lithium hydride, triethylamine borane and an organic solvent, and performing mechanical ball milling to obtain a mixture; and evaporating the solvent in the mixture, and carrying out heat treatment to obtain the lithium borohydride. Lithium borohydride is prepared through mechanical ball milling, the preparation process is high in safety coefficient, low in energy consumption, simple in process, mild in condition, adjustable in reaction process and easy to implement; the optimal yield is 80%, and the method is originally superior to other similar processes, has technical conditions for efficient mass production, and has a wide application prospect in hydrogen storage materials.

The invention relates to the technical field of molybdenum powder preparation, in particular to superfine molybdenum powder and a preparation method thereof.The preparation method comprises the steps that ammonium molybdate is subjected to ball milling and sieving to obtain ammonium molybdate powder, and the ammonium molybdate powder and a gluconic acid solution are mixed, stirred and dissolved to obtain a suspension solution; adding an azeotropic solution of n-butyl alcohol and water into the suspension solution, heating, stirring and dissolving to obtain a mixed solution; distilling the mixed solution, and cooling after the mixed solution is evaporated to obtain a solid ammonium molybdate precursor; the preparation method comprises the following steps: dispersing an ammonium molybdate precursor in an azeotropic solution, heating and roasting the ammonium molybdate precursor in air to obtain MoO3, carrying out first-stage reduction on the MoO3 in a hydrogen atmosphere to obtain MoO2, and then carrying out second-stage reduction to obtain the super molybdenum powder. And meanwhile, by regulating and controlling the mixing ratio of ammonium molybdate and the azeotropic solution, the morphology and size of the molybdenum powder can be remarkably adjusted, so that the molybdenum powder which is single and regular in morphology, uniform in distribution, high in yield, simple in preparation process and capable of being rapidly produced on a large scale is prepared.

The invention provides a rare earth catalyst for preparing array type carbon nanotubes and a preparation method of the rare earth catalyst, and relates to the technical field of rare earth catalysts. The preparation method provided by the invention comprises the following steps: mixing tetraethoxysilane and diaspore, and hydrolyzing to form composite gel; calcining the composite gel to obtain a porous carrier; dipping the porous carrier in the ligand solution, adding the cerium-containing feed liquid, stirring and mixing, and separating to obtain a catalytic precursor; dipping the catalytic precursor in the complexing solution, adding the iron-containing material liquid, stirring and mixing, and separating to obtain a catalytic intermediate; and depositing a carbon coating layer on the surface of the catalytic intermediate, and reducing in a hydrogen atmosphere to prepare the rare earth catalyst. According to the catalyst provided by the invention, in the growth process of the array type carbon nano tube, the diameter distribution of the carbon tube is concentrated by virtue of a confinement structure, and a Fe-Ce-O interface induces directional assembly of carbon atoms, so that the defect density of the tube wall is reduced.

The invention discloses a preparation method of low-cost in-situ doped continuous silicon carbide fiber, which comprises the following steps: by taking vinyl liquid polycarbosilane as a precursor, adding a boron monomer, an organic solvent and metallocene, and doping to prepare a doped polycarbosilane precursor; carrying out melt spinning on the doped precursor to obtain a doped precursor; placing the doped precursor in a mixed gas of an inert atmosphere and a boron-containing active atmosphere, and carrying out thermal crosslinking to obtain a doped crosslinked filament; and finally, pyrolyzing in an ammonia atmosphere to complete partial inorganic transformation of the doped cross-linked wire, then completing inorganic transformation in a hydrogen atmosphere, and finally performing high-temperature heat treatment on the doped cross-linked wire in an inert atmosphere to obtain the in-situ doped continuous silicon carbide fiber. Therefore, the problem of non-uniform coating of a ceramic-based composite material prefabricated body with a complex structure is solved, meanwhile, high cost and large damage to fibers of a secondary coating are avoided, and the composite material preparation technological process is simplified.