199 results about "Molybdenum trioxide" patented technology

The invention relates to the technical field of composite materials, in particular to a heat and sound insulation PVB intermediate film and a preparation method thereof. The problem that a PVB intermediate film is insufficient in heat insulation and aging resistance is solved. The preparation method comprises the following steps: pre-plasticizing PVB resin, shearing and mixing the pre-plasticized PVB resin and silane coupling agent modified enhanced nano cellulose, sequentially adding additives such as a plasticizer, molybdenum trioxide loaded lanthanum hexaboride, a composite light stabilizer and modified cerium oxide, and carrying out tape casting and hot pressing treatment to obtain the PVB intermediate film. Wherein the modified lanthanum hexaboride enhances infrared ray shielding, the composite light stabilizer and the modified cerium oxide synergistically improve the aging resistance, all the components are subjected to substance cooperation and process cooperation, comprehensive improvement of heat insulation, sound insulation and aging resistance of the PVB intermediate film is achieved, and the PVB intermediate film is suitable for the field of high-strength building glass.

The invention relates to the technical field of superfine molybdenum powder preparation, in particular to a preparation device and method for low-oxygen superfine molybdenum powder. The specific preparation device comprises a sublimation bin, a reaction area and a gas-solid separation bin which are sequentially connected, the reaction zone comprises a preheating zone, a reduction zone and a conversion zone; a part of the hydrogen pipeline and a part of the carbon monoxide pipeline are arranged in the preheating area; one end of the hydrogen pipeline extends to the reduction area and is used for providing preheated hydrogen and carrying out gas-phase reduction reaction on the preheated hydrogen and the gas-phase MoO3 subjected to heat preservation; one end of the carbon monoxide pipeline extends to the conversion area and is used for providing preheated carbon monoxide and reacting with water vapor to complete primary water vapor conversion; meanwhile, partial carbon monoxide is subjected to a disproportionation reaction to generate micro carbon powder, and the micro carbon powder and water vapor are subjected to a water gas reaction to complete secondary water vapor conversion. The problem that the oxygen content of existing superfine molybdenum powder prepared through gas-phase molybdenum trioxide reduction is too high is solved.

The invention discloses a molybdenum-vanadium-aluminum intermediate alloy and a low-cost preparation method thereof. The molybdenum-vanadium-aluminum intermediate alloy comprises the following chemical components in percentage by mass: 39-41% of Mo, 39-41% of V and the balance of Al. The method comprises the following steps: uniformly mixing vanadium oxide (tablets replace powder), molybdenum trioxide, metal aluminum, calcium fluoride, calcium oxide and a cold material according to a mass ratio of (28-32): (24-26): (32-35): (10-13): (1.5-4): (5-10); then putting the mixture into a graphite crucible for tamping treatment; and finally, the metal powder is directly ignited for a reduction reaction, and the molybdenum-vanadium-aluminum intermediate alloy can be obtained. According to the method, the recovery rates of the molybdenum and the vanadium are increased by adjusting the components and the ratio of the raw materials and the auxiliary materials and adopting a one-step aluminothermic reduction method, and the recovery rates of the molybdenum and the vanadium can reach 95 wt% or above and 96 wt% or above respectively.

The invention discloses an industrial flue gas denitration filter bag and a preparation method thereof, and relates to the technical field of flue gas denitration. The industrial flue gas denitration filter bag comprises PTFE (Polytetrafluoroethylene) fibers, PPS (Polyphenylene Sulfide) fibers, PI (Polyimide) fibers and PTFE loaded fibers. Wherein the PTFE loaded fiber is a PTFE fiber layer loaded with a modified molecular sieve catalyst; the modified molecular sieve catalyst takes a molecular sieve coated with modified nanorods as a carrier, a vanadium-titanium composite oxide as an active catalytic component and a cerium-titanium composite oxide as a co-catalytic component; the modified nanorod is a molybdenum-tungsten composite oxide modified cerium dioxide nanorod. By introducing the modified molecular sieve catalyst prepared from cerium dioxide nanorods, lanthanum nitrate, molybdenum trioxide and other raw materials, the denitration capacity, the ammonia escape prevention capacity, the sulfur poisoning resistance, the hydrothermal stability and the working life are further improved, and an active temperature window is widened. Therefore, the method has a wider application prospect.

A production process of electronic grade molybdenum dichloride dioxide comprises the following steps: S1, pretreatment: contacting molybdenum trioxide with a dilute acid solution at a low temperature for pickling to remove alkaline impurities and soluble metal impurities adsorbed on the surface, and drying for later use after washing; s2, wet synthesis: in an inert gas atmosphere, reacting the molybdenum trioxide subjected to acid pickling in the step S1 with concentrated hydrochloric acid of which the mass is 4-5 times of that of the molybdenum trioxide at 80-100 DEG C, and after the reaction is finished, evaporating and concentrating in a high-temperature chlorine atmosphere to generate a crude product of dichloromolybdenum dioxide; s3, primary sublimation purification; s4, complexing and decomplexing purification; and S5, secondary sublimation purification: using a quartz sublimation tower to carry out vacuum sublimation on the secondary decomplexed molybdenum dichloride obtained in the step S34, and collecting sublimation condensate to obtain the electronic grade molybdenum dichloride. The final product purity of the production process is greater than or equal to 6N, and the process can be used for large-scale production.

This invention belongs to the field of single-crystal material preparation technology, specifically relating to a molybdenum trioxide single-crystal ribbon and its preparation method. During the calcination of a molybdenum source, the ribbon is contacted with a structure-directing agent composed of alkali metal salts and metals other than molybdenum in Group 6, or alkaline earth metal salts and metals other than molybdenum in Group 6. After cooling, the molybdenum trioxide single-crystal ribbon is obtained. This invention does not require complex template guidance, the structure-directing agent is simple and readily available, and it enables molybdenum trioxide crystals to grow along a specific direction, resulting in a highly crystalline molybdenum trioxide single-crystal ribbon.

The invention belongs to the technical field of photocatalysis and environmental governance, and particularly relates to a composite photocatalyst, in particular to a graphite-phase carbon nitride / molybdenum trioxide composite photocatalyst as well as a preparation method and application thereof. The method comprises the following steps: S1, dispersing ammonium heptamolybdate in deionized water, adjusting the pH value of the solution to 0.5 + / -0.3 by using sulfuric acid, stirring and centrifuging the formed system, and carrying out vacuum drying to obtain a molybdic acid precursor; s2, mixing melamine and the molybdic acid precursor, calcining the formed mixture, and naturally cooling to room temperature after calcining is finished, so as to obtain the composite photocatalyst. Tests prove that the prepared catalyst has excellent cycling stability, still keeps high catalytic activity after being recycled for multiple times, and has a good industrial application prospect.

The invention belongs to the technical field of lithium battery materials, and particularly discloses a porous carbon negative electrode material for a lithium ion battery and a preparation method of the porous carbon negative electrode material. Firstly, a copolymer is prepared through staged polymerization of a functional monomer and a chain transfer agent; secondly, taking nano molybdenum trioxide and zinc acetate dihydrate as raw materials, and performing ball milling and roasting to form a core-shell template; then, mixing and sieving the copolymer, the core-shell template, sodium chloride and the polymethyl methacrylate microspheres to obtain a precursor; and finally, carrying out multi-stage heating carbonization and post-treatment on the precursor to obtain the porous carbon negative electrode material. The obtained negative electrode material has a hierarchical porous structure and a high specific surface area, synergistic doping of multiple elements such as nitrogen, phosphorus and molybdenum is realized, rapid transmission and efficient storage of lithium ions are effectively promoted, the rate capability and cycling stability of a battery are remarkably improved, polarization impedance is reduced, and meanwhile, the electronic conductivity and interface stability of the material are further optimized; excellent comprehensive electrochemical performance is shown in the application of a high-energy-density lithium ion battery.

The invention discloses a flame-retardant PVC (polyvinyl chloride) wood-plastic plate which is prepared from the following raw materials in parts by weight: 100 parts of SG-7 type PVC resin; 20-30 parts of modified wood powder; the composite flame retardant is composed of ammonium polyphosphate, aluminum hydroxide, molybdenum trioxide and zinc borate according to the weight ratio of 15: 20: 16: 4; the mass ratio of the aluminum-titanium composite coupling agent to the wood flour is 1: 100; 5-8 parts of a calcium-zinc stabilizer; the lubricant is composed of polyethylene wax, paraffin and calcium stearate according to the weight ratio of 1: 1: 1; and 5-10 parts of an acetyl butyl citrate plasticizer. The invention relates to the technical field of polymer composite materials, in particular to a flame-retardant PVC wood-plastic plate and a preparation method thereof.The flame-retardant PVC wood-plastic plate and the preparation method thereof have the remarkable advantages that due to a composite flame retardant, the oxygen index of the plate reaches 32.1%, the combustion performance reaches the UL94V-0 level, and the smoke density is reduced by 72.1%; the tensile strength, the impact strength and the bending strength are respectively improved by 339.6%, 59.1% and 179.5% when the wood powder is treated by the aluminum-titanium coupling agent; the extrusion temperature of 150-175 DEG C and the screw rotating speed of 12-18 r / min are accurately controlled, the problems of wood powder carbonization and flame retardant decomposition are avoided, and the quality consistency is guaranteed.

The invention relates to an interface and fiber modified synergistic composite modified cement-based material and a preparation method thereof. On the basis of collaborative design of interface modification and grading processes, tin-titanium alloy sand, grass ash powder, nano molybdenum trioxide and sisal hemp / ramie fibers are used for constructing a composite system, and component dispersion and interface combination are optimized through a titanate coupling agent: the mechanical strength is innovatively improved through a three-dimensional network enhanced structure, and plant fibers cooperatively inhibit microcrack propagation through rigidity and softness; and hydrophobic modification of the nano material is combined with a pore filling mechanism to enhance impermeability and freezing resistance. Tests show that the comprehensive performance of the material is remarkably superior to that of a common cement-based material, the mechanical strength, crack resistance and durability are comprehensively improved, and drying shrinkage and freeze-thaw damage are greatly reduced. The graded mixing process ensures that the material is homogeneous and stable, and is suitable for ocean engineering, alpine regions and anti-seismic buildings. The raw materials are environment-friendly, the cost advantage is outstanding, and the requirements of green building material development are met.

The present invention belongs to the technical field of composite catalytic material preparation and relates to a polypyrrole-coated defective molybdenum trioxide catalyst for use in oxidative desulfurization. A method for preparing the catalyst is also disclosed, comprising uniformly dispersing molybdenum powder in n-butanol, slowly adding hydrogen peroxide with continuous stirring, and adding pyrrole when the reaction solution turns bright yellow and transparent. Stirring is continued at room temperature overnight. The solution is placed in an autoclave and subjected to a hydrothermal reaction at 100-160°C for 12-20 hours. After cooling to room temperature, the reaction is centrifuged, and the precipitate is washed with deionized water and anhydrous ethanol, respectively. The resulting precursor is collected and vacuum dried to obtain the catalyst. Using molybdenum powder and pyrrole as raw materials, the present invention employs a one-step hydrothermal synthesis method to produce a polypyrrole-coated defective molybdenum trioxide catalyst with abundant surface oxygen vacancies. This catalyst enhances light absorption efficiency and photothermal conversion efficiency, thereby improving photocatalytic oxidative desulfurization performance. The prepared composite catalyst exhibits advantages such as good selectivity, high stability, and a stable structure.

This invention discloses a high-performance V-Mo-Ti-based low-temperature SCR denitration catalyst, using titanium dioxide as a support, with vanadium pentoxide and molybdenum trioxide loaded on the support as active components; wherein, based on the mass of the support, the loading of V₂O₅ is 1.0 wt%–3.0 wt%, and the vanadium element on the catalyst surface contains V 5+ and V 4+ The molar ratio is 3.0:1 to 4.0:1; the loading of MoO3 is 1 wt% to 5.5 wt%. Compared with conventional catalysts, this invention can significantly improve the denitrification activity and efficiency in the low-temperature range, with the K value increasing from 9.14 to 19.41. The raw materials used in this invention are inexpensive, the preparation method is simple, the reaction conditions are mild, and it can endow general catalysts with low-temperature catalytic ability, thus having good economic benefits.

The application relates to the technical field of molybdenum trioxide production, and particularly discloses a preparation method of high-purity molybdenum trioxide. The method comprises the following steps: preparing a complexing impurity removing agent by taking diatomite, citric acid, ethylenediaminetetraacetic acid disodium and tartaric acid as raw materials; dissolving industrial ammonium dimolybdate to obtain an ammonium molybdate solution, adding the impurity removing agent into the ammonium molybdate solution, complexing impurities under an acidic condition, and deeply removing the impurities through flocculation and precision filtration; adjusting the alkalinity of the filtrate, and cooling and crystallizing the filtrate to obtain high-purity ammonium molybdate; and finally performing program-controlled temperature calcination in an atmosphere with a specific oxygen content by using a quartz boat coated with a composite coating on the inner wall, so as to obtain high-purity molybdenum trioxide. The application combines multi-stage purification with an accurate calcination process, can efficiently remove impurities in raw materials, and has stable process flow; the obtained molybdenum trioxide product has high purity, good crystal morphology, good process stability and good industrialization prospect.

The application belongs to the technical field of semiconductor manufacturing, and particularly relates to a preparation method of an alpha-phase molybdenum trioxide film, a back-gate silicon-based field effect transistor and a preparation method thereof. A precursor is dispersed in an organic solvent to obtain a precursor solution, the precursor containing molybdenum elements and sulfur elements; the precursor solution is coated on a substrate surface to obtain a substrate with a precursor wet film; the substrate with the precursor wet film is sequentially heat-treated, subjected to first annealing treatment in a protective gas atmosphere, and subjected to second annealing treatment in an oxidizing atmosphere to obtain an alpha-phase molybdenum trioxide film. The alpha-phase molybdenum trioxide film obtained by the application has the characteristics of high film quality, excellent interface characteristics and high crystal phase purity, can form a high-quality, undamaged interface with a two-dimensional semiconductor channel as a gate dielectric layer material, and can realize ultra-thin EOT, thereby solving the problems of large leakage current and weak gate control capability of the FET in the prior art.

This molybdenum trioxide powder has a specific surface area, as measured using the BET method, of 100 mｍ2 / g-500 m2 / g. The molybdenum trioxide powder may have a median diameter D50 of 5-1000 nm, as determined using a dynamic light scattering method. The molybdenum trioxide powder may have a purity of 99 mass% or more. The molybdenum trioxide powder may include molybdenum trioxide having a β crystal structure.

The invention relates to a graphene-coated molybdenum dioxide nanorod composite material as well as a preparation method and application thereof. The composite material is of a core-shell structure and takes a molybdenum dioxide nanorod as a core and a graphene layer as a shell; the graphene layer is formed by high-temperature carbonization of polyaniline, and the thickness of the graphene layer is 10-80 nm. The preparation method comprises the following steps: dissolving a molybdenum source in a nitric acid aqueous solution for hydrothermal reaction to prepare a molybdenum trioxide nanorod precursor; dispersing the molybdenum trioxide nanorod precursor in an acidic solution, sequentially adding aniline and ammonium persulfate under a stirring condition, and reacting to obtain a polyaniline / molybdenum trioxide composite precursor; and drying the composite precursor, and carrying out high-temperature calcination to obtain the graphene-coated molybdenum dioxide nanorod composite material. Compared with the prior art, the composite material has the high conductivity of graphene and the chemical activity of molybdenum dioxide, and shows excellent removal efficiency and cycling stability on lead ions in the capacitive deionization process.

The application provides a method and application for reducing molybdenum trioxide to generate molybdenum dioxide or molybdenum carbide, which comprises the following steps: dispersing MoO3 powder in a mixed solution of monohydric alcohol and polyhydric alcohol, adding a triblock copolymer P123 stabilizer, and obtaining a suspension which is subjected to microwave-assisted solvothermal reaction, centrifugation or filtration and washing, and then brown H 0.93 The MoO3 / C precursor microspheres are placed in an argon plasma environment and calcined at a high temperature of 500-600 DEG C for 30-60 min to obtain brown-black MoO2 / C microspheres; or the H 0.93 The MoO3 / C precursor is placed in a hydrogen-argon plasma environment and calcined at a high temperature of 500-600 DEG C for 30-60 min to obtain gray Mo2C / C microspheres. The MoO2 / C and Mo2C / C materials prepared by the application have nanocrystalline characteristics and excellent electrochemical performance, and have a good commercial application prospect as negative electrode materials of lithium batteries.

The application provides a molybdenum trioxide extraction method, and belongs to the field of extraction metallurgy. The molybdenum trioxide extraction method provided by the application comprises the following steps: vacuum smelting a molybdenum-containing material to obtain sublimates, and cooling the sublimates to obtain the molybdenum trioxide; the molybdenum content in the molybdenum-containing material is 37.42-46.31 wt%, and the oxygen content is 30.74-38.13 wt%; the temperature of the vacuum smelting is 880-1200 DEG C, and the vacuum degree is 0.47-10 Pa; and the cooling rate of the cooling is 5-10 DEG C / min. The molybdenum trioxide is obtained by decomposing molybdate in the molybdenum-containing material through vacuum smelting, and the original molybdenum trioxide in the molybdenum-containing material sublimates under high-temperature conditions to obtain high-purity molybdenum trioxide, thereby effectively improving the extraction efficiency of the molybdenum trioxide; and the extraction method is simple, the low-grade molybdenum-containing material is used as the raw material, the extraction cost is lower, and the environment is not polluted.

A molybdenum trioxide powder, which contains an aggregate of primary particles comprising a crystal structure of molybdenum trioxide, the crystal structure comprising α-crystals having an average crystallite size of 50 nm or less. The median particle diameter D50 of the primary particles, which is obtained by a dynamic light scattering method, is 2000 nm or less. 50 is 2000 nm or less.

The invention discloses a preparation method of a gasoline selective hydrogenation catalyst, which comprises the following steps: (1) adding a niobium-containing precursor into bottom water of a reactor, adding an aluminum salt solution and a precipitant in a parallel flow manner, carrying out gelling reaction, pulping molybdenum trioxide after gelling, carrying out aging reaction, and washing, filtering and drying an aging product to obtain modified alumina dry glue powder; (2) uniformly mixing the modified alumina dry glue powder, a peptizing agent and an extrusion aid, carrying out extrusion molding, drying and roasting to obtain a carrier, and carrying out vulcanization treatment; (3) carrying out saturated impregnation on the carrier vulcanized in the step (2) by using liquid olefin, and then carrying out closed heat treatment under a CO2 atmosphere condition with a certain concentration; and (4) impregnating the heat-treated material obtained in the step (3) with an impregnation liquid containing active metal Co, drying, roasting and vulcanizing to obtain the hydrodesulfurization catalyst. The catalyst disclosed by the invention has relatively high desulfurization activity and selectivity when being applied to a gasoline selective hydrogenation process.

The present application relates to a kind of low sulfur high performance fuel oil production device, it relates to fuel oil production technical field.Low sulfur modified residual oil, hydrogenation low sulfur raffinate are used as main raw material, auxiliary agent A, auxiliary agent B prepared by special oil device are matched, reaction conditions are accurately controlled through DCS system, low sulfur high performance marine fuel oil is prepared in low temperature mild environment;Device integrates vacuum deep pull and viscosity reduction cracking combined process, light fraction can be deep-processed into three kinds of base oil, etc.Additional value products, heavy fraction is reduced in viscosity by viscosity reduction cracking, and low-temperature fluidity is improved;Auxiliary agent B is prepared by dithiophosphoric acid, molybdenum trioxide, epoxy succinic acid polymer, 2,6-naphthalene dicarboxylic acid, anhydrous toluene, phosphorous acid;Fuel oil prepared by the present application, sulfur content is lower, environmental protection is better, low-temperature fluidity is improved, and combustion efficiency is better.

A molybdenum trioxide powder contains an aggregate of primary particles having a β crystal structure of molybdenum trioxide. The molybdenum trioxide powder has a MoO3 content ratio of 99.6% or more measured by X-ray fluorescence (XRF), and has an average particle diameter of the primary particles of 1 μm or less. A method for producing the above molybdenum trioxide powder includes vaporizing a molybdenum oxide precursor compound to form molybdenum trioxide vapor, and cooling the molybdenum trioxide vapor.

The present application relates to geothermal resource development technical field, specifically to a kind of high heat-conducting material resistant to CO2 corrosion for cementing and its preparation method, the material includes 45wt. 70wt. 20wt. 40wt. 10wt. 15wt. By weight percentage Heat-conducting material, corrosion-resistant material and toughening material, heat-conducting material is formed by heat-conducting reinforced material and reinforcing material by mass ratio (8-12):(6-9) Mixed, the corrosion-resistant material is formed by nano-molybdenum trioxide, chlorite powder and acidified serpentine powder by mass ratio (9-12):(4-6):(4-5) Mixed.The high heat-conducting material resistant to CO2 corrosion for cementing of the present application has the properties of high temperature resistance, toughening, gas channeling prevention, corrosion resistance and heat conduction by mutual cooperation and mutual cooperation between components.

The application discloses a preparation method of a supported high-dispersion molybdenum phosphide catalyst, and comprises the following steps: S1, dissolving molybdenum acetylacetonate and ammonium hypophosphite in an aqueous solution of N,N-dimethylformamide to obtain an impregnation solution; S2, immersing a carrier in the impregnation solution, then drying and reducing to obtain a supported molybdenum phosphide catalyst. The hydrogenation activity and the hydrodesulfurization activity of the prepared molybdenum phosphide catalyst are higher than those of MoP catalysts prepared by a temperature programmed reduction method and a molybdenum trioxide reduction method with ammonium hypophosphite, and the molybdenum phosphide catalyst has very high hydrodesulfurization activity on p-benzothiophene.

The invention discloses a low-emission scratch-resistant polypropylene composite material and a preparation method thereof, and relates to the technical field of high polymer materials. The low-emission scratch-resistant polypropylene composite material is prepared from the following raw materials: polypropylene resin, functionalized molybdenum trioxide porous microspheres, mineral powder, a flexibilizer, an antioxidant and a light stabilizer. The organic siloxane is grafted to the functionalized molybdenum trioxide porous microspheres, and low-molecular substances such as formaldehyde, acetaldehyde and the like generated in the production process are adsorbed by utilizing the porous structures of the functionalized molybdenum trioxide porous microspheres, so that the odor of the material is reduced; and meanwhile, the grafted organosiloxane reduces the surface friction coefficient and provides lasting scratch resistance. The synthesis raw materials of the functionalized molybdenum trioxide porous microspheres are easy to purchase, economical, environment-friendly and efficient, and the production cost is reduced.

The application discloses a wafer-level single-layer MoS2 film and a preparation method thereof, and the method comprises the following steps: placing sulfur powder and molybdenum trioxide powder as reaction precursors into two quartz boats respectively, and placing the quartz boat containing the sulfur powder, the quartz boat containing the molybdenum trioxide powder and a C-surface sapphire substrate vertically placed in the direction of the air flow into a first temperature zone, a second temperature zone and a third temperature zone of a single-tube CVD tube furnace respectively; introducing a carrier gas into the single-tube CVD tube furnace after cleaning, and heating the sulfur powder, the molybdenum trioxide powder and the C-surface sapphire substrate when the preset furnace pressure is reached, so that a wafer-level single-layer MoS2 film with good uniformity and high quality is formed, and the technical problems of low yield and poor uniformity of the two-dimensional MoS2 film obtained by mechanical peeling are solved.

The present application belongs to the field of gas sensing technology, and relates to a hydrogen sensor, and provides a humidity gain film of a molybdenum trioxide hydrogen sensor, which is used for solving the problems of slow response time and sensitivity decline of the existing hydrogen sensor caused by the influence of environmental humidity, and is jointly formed with a palladium-based hydrogen-sensitive film and a substrate to form the hydrogen sensor. Through the design of a thermal evaporation process, a molybdenum trioxide film with a thickness of 2-10 nm and a non-continuous nano-island structure on the surface is successfully deposited on the surface of the palladium-based hydrogen-sensitive film to serve as the humidity gain film. Through the unique reverse hydrogen release effect of the molybdenum trioxide film in a humidity environment, hydrogen atoms are accelerated to contact the active sites on the surface of the palladium film, and the influence of water molecules on the response speed of the palladium-based hydrogen sensor is weakened, that is, while allowing hydrogen molecules to diffuse through to the surface of the palladium-based hydrogen-sensitive film, the diffusion of water molecules is inhibited on the surface of the humidity gain film, and finally the target of rapid detection of hydrogen leakage in a humidity environment is achieved.

The application belongs to the field of catalytic material preparation, and particularly relates to a molybdenum-iron catalyst for methanol oxidation to formaldehyde with high reaction intensity and a preparation method thereof. The catalyst is prepared by the following steps: adding dry molybdenum trioxide powder and a ferric nitrate solution into a hydrothermal reactor, adding ammonia water into the hydrothermal reactor under stirring to control the pH value of the mixed solution; after uniform stirring, the hydrothermal reactor is sealed and placed into an oven for hydrothermal treatment, and then cooled to room temperature; the obtained precursor is filtered, dried and calcined to obtain the catalyst. The preparation method is simple in operation, low in production cost, small in environmental pollution, and does not require many auxiliary facilities. The hydrothermal treatment can strengthen the contact between the active center and the carrier, and the obtained catalyst is high in crystallinity, good in high-temperature stability, high in formaldehyde selectivity, and can be applied to the reaction condition of methanol oxidation to formaldehyde with high reaction intensity.

The invention provides a process for preparing molybdenum and tungsten oxyhalide compounds which are useful in the deposition of molybdenum and tungsten containing films on various surfaces of microelectronic devices. In the process of the invention, a molybdenum or tungsten trioxide is heated in either a solid state medium or in a melt-phase reaction comprising a eutectic blend comprising alkaline and / or alkaline earth metal salts. The molybdenum or tungsten oxyhalides thus formed may be isolated as a vapor and crystallized to provide highly pure precursor compounds such as MoO2Cl2.

The invention discloses a two-dimensional semiconductor p-type field effect transistor based on transition metal oxide contact and a preparation method thereof, and relates to the technical field of semiconductor micro-nano electronic devices, and the preparation method comprises the steps: forming a single-layer tungsten diselenide on a substrate as a channel layer; defining pattern windows of a source electrode and a drain electrode on the surface of the channel layer to form an electrode region and a non-electrode region; sequentially depositing molybdenum trioxide and gold on the pattern windows of the source electrode and the drain electrode by adopting a thermal evaporation process to form a molybdenum trioxide / gold composite electrode structure; and removing the photoresist and sediments above a non-electrode region through a stripping process to prepare the two-dimensional semiconductor p-type field effect transistor based on transition metal oxide contact. The preparation of the high-performance two-dimensional semiconductor p-type field effect transistor is realized by introducing the ultrahigh work function molybdenum trioxide as the buffer layer and combining a mild process.