316 results about "Molybdenum carbide" patented technology

The invention belongs to the technical field of catalysts, and particularly relates to a supported Co-based catalyst with a nano molybdenum carbide auxiliary as well as a preparation method and application of the supported Co-based catalyst. The preparation method comprises the following steps: depositing molybdenum oxide on the surface of a carrier material by adopting an atomic layer deposition method, then carrying out carburizing treatment to obtain a molybdenum carbide catalyst, depositing cobalt oxide on the surface of the molybdenum carbide catalyst by adopting the atomic layer deposition method, and then carrying out reduction treatment to obtain the supported cobalt-based catalyst with the nano molybdenum carbide assistant. According to the preparation method provided by the invention, the size of molybdenum carbide and the dispersity and valence state of cobalt are controlled by regulating and controlling the deposition times of molybdenum oxide, and the prepared catalyst has excellent catalytic activity and stability in the hydroformylation reaction of long-chain olefin with the carbon atom number being greater than or equal to 5.

The invention discloses a rare earth oxide modified high-entropy hard alloy and a preparation method thereof. A high-entropy hard phase (high-temperature calcination), a high-entropy binding phase and rare earth oxide are adopted, grinding, pressing and air pressure sintering at the temperature of 1450-1550 DEG C are conducted, and the high-entropy hard phase is prepared from tungsten carbide, titanium carbide, zirconium carbide, yttrium carbide, manganese carbide, chromium carbide and molybdenum carbide; the high-entropy binding phase comprises the following components: cobalt and a CoCrFeNi-series high-entropy alloy; and the component of the rare earth oxide is Y2O3 or Nd2O3. The prepared rare earth oxide modified high-entropy hard alloy has the advantages of high strength, high compactness, high hardness, high wear resistance and the like.

The invention discloses a molybdenum carbide / nitrogen-doped carbon composite material and a preparation method and application thereof, and belongs to the technical field of new energy materials and devices. The preparation method comprises the following steps: uniformly mixing ammonium molybdate, glucose and g-C3N4, and carrying out hydrothermal and high-temperature calcination treatment to obtain a composite material (Mo2C / NC) in which a nano Mo2C electrocatalyst is dispersed and distributed on a nitrogen-doped carbon matrix. The nitrogen-doped carbon in the composite material has a hierarchical porous structure, so that the electrolyte permeation and ion transmission capabilities are enhanced; the nitrogen-doped active sites not only enhance the adsorption performance of the porous carbon on polysulfide, but also improve the catalytic activity by optimizing the coordination structure of Mo2C; mo2C can chemically adsorb and efficiently catalyze reversible conversion of polysulfide, and the utilization rate of active substances is increased. When the composite material is used as a positive electrode additive of a lithium-sulfur battery, dissolution and shuttling of polysulfide can be effectively inhibited, so that the battery has high specific capacity, rate capability and excellent cycle reversibility.

The present invention relates to a method of producing a catalyst structure comprising molybdenum carbide on a porous carrier compound, comprising preparing a mixture comprising a porous carrier compound and a molybdenum oxide; shaping the mixture into a porous green body by a 3D-printing technique; and carburizing the porous green body by exposing the mixture to a reducing atmosphere comprising a carbon-comprising gas at a temperature between 650 °C and 1000 °C, thereby converting at least a portion of the molybdenum oxide into molybdenum carbides and obtaining a catalyst structure having an elevated temperature; cooling the catalyst structure having an elevated temperature to room temperature in an atmosphere which is inert with respect to molybdenum oxide, thereby obtaining the catalyst structure; wherein the concentration of molybdenum oxide in the mixture is such that a ratio of the molybdenum content in the mixture to the BET surface area of the porous carrier compound in the mixture is equal to or lower than 2.5 * 10-5 molMo / m², wherein the molybdenum content in the mixture is measured by ICP-OES and the BET surface area is measured by multi-point BET analysis of a N2 adsorption isotherm. The invention further relates to a catalyst structure obtained by the methods of the invention.

The invention discloses a carbon-doped non-noble metal high-entropy alloy hydrogen evolution catalytic electrode and a preparation method thereof, and belongs to the technical field of water electrolysis hydrogen production. The preparation method comprises the following steps: (1) blending four metal powder of Fe, Co, Ni and Mo with carbon powder, ball-milling, standing and passivating to obtain mixed powder; and (2) carrying out compression molding on the mixed powder obtained in the step (1), and sintering. The preparation method is simple in process, the hydrogen evolution catalytic electrode can be obtained only through two steps of mechanical alloying and pressureless sintering, operation is easy and convenient, large-scale preparation can be achieved, and industrialization is easy; through a carbon doping mode, a transition metal carbide-molybdenum carbide and quaternary high-entropy alloy synergistic effect is formed in the electrode material, the free energy of a hydrogen intermediate is obviously reduced, the mass transfer process in electrochemical reaction is facilitated, and the electrode material has excellent hydrogen evolution catalytic performance and is suitable for water electrolysis hydrogen evolution catalytic reaction in an alkaline environment; the hydrogen production efficiency can be improved, and the energy consumption is reduced.

The invention provides a method and a system for screening a catalyst for preparing methanol by reducing carbon dioxide. The method comprises the following steps: calculating an optimized structure (CONNTCAR) and an energy value (OUTCAR) of a TM (at) Mo2C model; the formation energy Ef of the TM and Mo2C model is calculated; by calculating a POURBAIX graph, the coverage conditions of other species of molybdenum carbide under the working potential under the chemical reaction are determined; detailed electrocatalytic CO2RR and HER mechanisms of these catalysts are systematically discussed through density functional theory (DFT) calculation. The invention solves the technical problems of high experimental research cost and high difficulty in improvement of the performance of methanol preparation by carbon dioxide reduction due to undefined reaction mechanism of transition metal loaded molybdenum carbide for preparation of methanol by carbon dioxide reduction.

A gradient multilayer nano Ti (C, N)-based metal ceramic and a preparation method thereof relate to the field of powder metallurgy, and the method comprises the following steps: S1, mixing 64.9% by mass of titanium carbonitride, 23% by mass of tungsten carbide, 8% by mass of cobalt, 4% by mass of molybdenum carbide and 0.1% by mass of graphene nanosheets to obtain mixed powder I; mixing 60.9% of titanium carbonitride, 23% of tungsten carbide, 8% of cobalt, 8% of molybdenum carbide and 0.1% of graphene nanosheets to obtain mixed powder II; and S2, the mixed powder I and the mixed powder II are added into a mold layer by layer, three layers of mixed powder with the surface layer being the mixed powder II layer and the core layer being the mixed powder I layer are obtained, spark plasma sintering is carried out, and the gradient multi-layer nano Ti (C, N)-based metal ceramic is obtained. According to the Ti (C, N)-based metal ceramic and the preparation method thereof, different molybdenum carbide mass proportions of the surface layer and the core layer are controlled, a hard phase enrichment area is formed on the surface layer, a binding phase enrichment area is formed on the inner core part, the Vickers hardness can be improved through hard phase enrichment, the fracture toughness can be improved through binding phase enrichment, and therefore the Ti (C, N)-based metal ceramic with the hardness and the fracture toughness is obtained.

The invention discloses a WC-TiC-Mo2C-carbonfiber-8Co hard alloy and a preparation method thereof, and relates to the technical field of hard alloy preparation, the method comprises the following steps: S1, mixing tungsten carbide, cobalt, titanium carbide, molybdenum carbide and carbon fibers to obtain mixed powder; s2, the mixed powder is subjected to pre-pressing forming, and a hard alloy intermediate is obtained; and S3, the hard alloy intermediate is subjected to high-temperature and high-pressure sintering, and the WC-TiC-Mo2C-carbon fiber-8Co hard alloy is obtained. Wherein the conditions of high-temperature and high-pressure sintering are as follows: the sintering temperature is 1300-1450 DEG C, the sintering pressure is 2-6 GPa, and the heat preservation time is 2-10 minutes. By means of the preparation method, the hardness, toughness and other mechanical properties of the hard alloy can be further improved.

This invention belongs to the field of catalytic material preparation technology, specifically relating to a method for preparing high specific surface area pure phase α-type molybdenum carbide by hydrogen intercalation modification of MoO3 and its application, including the following steps: (1) adding MoO3 powder to hydrochloric acid and dispersing it to prepare a mixture of MoO3 and hydrochloric acid; (2) adding metal powder to the mixture in step (1) and performing pre-reduction treatment by in-situ hydrogenation of the metal and hydrochloric acid to prepare H x MoO3 precursor; (3) H prepared in step (2) x The MoO3 precursor is carbonized under a carbon source gas to obtain a pure α-type molybdenum carbide with a high specific surface area. This method is simple and effective, avoids the use of corrosive NH3 gas during carbonization, and does not require a metal as a medium, thus solving the current problem of not being able to prepare metal-free modified pure α-MoC in one step.

Molybdenum(0) coordination complexes comprising ligands which each coordinate to the metal center by nitrogen or phosphorous are described. Methods for depositing molybdenum-containing films on a substrate are described. The substrate is exposed to a molybdenum precursor and a reactant to form the molybdenum-containing film (e.g., elemental molybdenum, molybdenum oxide, molybdenum carbide, molybdenum silicide, molybdenum nitride). The exposures can be sequential or simultaneous.

The present invention provides a high-temperature resistant and highly lubricating coating for aviation fastener wires, wherein the raw materials of the coating include, by weight, 20-30 parts of graphite, 30-40 parts of molybdenum disulfide, 3-10 parts of molybdenum carbide, 20-30 parts of silicate, 1-5 parts of silicon powder, and 15-30 parts of diluent. In the present invention, by using materials such as graphite and molybdenum disulfide in a specific proportion, the raw materials work together to obtain a lubricating coating having excellent high-temperature resistance and high lubrication effects. The coating has excellent adhesion at room temperature, and can avoid the coating from being peeled off due to scratches on moving wires; it can still maintain excellent adhesion and good lubricity at high temperatures, and the coated sample wire is taken out for inspection after being kept in an oven (temperature 850°C) for 2 minutes, and the coating is intact and there is no discoloration or peeling.

The invention discloses a high-dispersion and small-particle-size alpha-MoC1-x / SiO2 catalyst as well as a preparation method and application thereof. The catalyst is composed of alpha-MoC1-x nanoparticles dispersed on a silicon dioxide carrier, the alpha-MoC1-x / SiO2 catalyst is generated in a three-dimensional SiO2 confined network in a limited manner, wherein the three-dimensional SiO2 confined network is constructed by in-situ polycondensation of silica sol under the condition that the pH value is 2.3-2.8, and the molybdenum content is 30-60%; the average particle size of the alpha-MoC < 1-x > nanoparticles is 1.0-2.2 nm, and the alpha-MoC < 1-x > nanoparticles are highly dispersed in the SiO2 confinement structure; the alpha-MoC1-x nano-particles are face-centered cubic phase molybdenum carbide, and the mass fraction of the face-centered cubic phase molybdenum carbide is larger than or equal to 90 wt%. The alpha-MoC1-x / SiO2 obtained by the invention can realize higher methanol selectivity and intrinsic activity under the condition of 140-180 DEG C, and can stably operate for 100 hours. The invention provides a novel small-particle-size and high-dispersion molybdenum carbide catalytic material and a preparation strategy thereof for preparing methanol through low-temperature and high-selectivity CO2 hydrogenation.

MAX-phase Mo2Ga2C is used as a matrix, a liquid phase corrosion method is utilized, the preparation of the two-dimensional vacancy doped molybdenum carbide (Mo2-CTz) nano material is realized through excessive corrosion, and the two-dimensional vacancy doped molybdenum carbide (Mo2-CTz) nano material is applied to the aspect of a hybrid supercapacitor. Compared with other reported MXene materials, the influence of vacancy doping measures on the Mo2CTz nanometer material is studied, the layered MAX ceramic powder is excessively corroded through hydrofluoric acid, vacancies are introduced into a metal layer, vacancy doping of MXene is achieved, and the capacitive performance of the MXene is improved. And vacancy defects are introduced, so that the interlayer spacing of MXene can be increased, activation sites on the surface of the layered structure can be increased, the conductivity of the two-dimensional material can be improved, the utilization rate of pseudocapacitance active sites of the two-dimensional material can be improved, and finally the capacitive performance of the Mo < 2->-CTz-based electrode can be enhanced. The successful development of the two-dimensional vacancy doped Mo < 2->-CTz self-supporting film electrode material lays a foundation for the practical application of electrochemical energy storage devices such as hybrid supercapacitors and ion batteries.

The invention belongs to the technical field of nano confinement, and provides a method for preparing multi-grain-boundary molybdenum carbide nano-particles through a precise double-confinement path and application of the multi-grain-boundary molybdenum carbide nano-particles. The preparation method comprises the following steps of: coating polymer hydrogel on a carbon carrier in situ by taking a Ni-porphyrin cross-linking agent as a nickel source and phosphomolybdic acid as a molybdenum source, and preparing a Ni and PMo12 ortho-position double-confinement carbon-coated precursor by accurately controlling the ratio of the phosphomolybdic acid to the cross-linking agent and cross-linking through a self-confinement Ni-containing cross-linking agent Ni porphyrin cross-linking agent; the proportion of a Mo source to a cross-linking agent is precisely limited, and the multi-grain-boundary molybdenum carbide catalyst regulated and controlled by Ni atoms is prepared based on double-confinement pyrolysis. The molybdenum carbide catalyst containing a plurality of crystal boundaries is accurately prepared on the carbon substrate, and the OER catalytic performance of the molybdenum carbide catalyst is researched. Accurate regulation and control on the defect state of the molybdenum carbide nanosheet are realized, so that the intrinsic catalytic activity of molybdenum carbide is improved. The prepared catalyst shows excellent electrochemical performance in electro-catalysis oxygen evolution, and efficient water electrolysis oxygen evolution is achieved.

The invention belongs to the technical field of catalyst preparation, and particularly relates to a preparation method and application of a catalyst for synthesizing deuterated ammonia. The preparation method comprises the following steps: S1, adding molybdenum carbide into a hydrofluoric acid solution, magnetically stirring for 72-96 hours, washing and centrifuging with water, and repeatedly washing and centrifuging until the pH (Potential of Hydrogen) gt; 5, obtaining acid etching molybdenum carbide; s2, adding an alkaline solution into the acid-etched molybdenum carbide, carrying out ultrasonic treatment at room temperature until the pH value of the solution is 7, and then carrying out centrifugal solid-liquid separation to obtain layered molybdenum carbide; and S3, mixing the cobalt chloride hexahydrate solution and molybdenum carbide at 400-600 DEG C to react for 3-6 hours, and performing vacuum freeze drying to obtain the Co / molybdenum carbide catalyst. The catalyst prepared by the method is applied to synthesis of deuterated ammonia by reaction of nitrogen and deuterium gas, and is low in cost, pollution-free, high in conversion rate and simple to prepare.

The application provides a preparation method and application of a molybdenum carbide loaded jute derived porous carbon material, and belongs to the technical field of electrochemical catalysis. The preparation method comprises the following steps: pretreating jute fibers to obtain jute powder; placing the jute powder in a molybdenum compound containing solution to obtain a mixture, the jute powder in the mixture adsorbing the molybdenum compound, and the mass ratio of the jute powder to the molybdenum compound in the molybdenum compound containing solution being any value in 1:(2.5-6.25); and carbonizing the jute powder adsorbing the molybdenum compound at 800-900 DEG C to obtain the molybdenum carbide loaded jute derived porous carbon material. The jute fiber derived porous carbon is used as a carrier, and the precursor is fully adsorbed and combined in the molybdenum compound containing solution. By adjusting the mass ratio and the carbonization temperature, the highly dispersed and stably loaded molybdenum carbide is realized, the structural stability and catalytic activity of the molybdenum carbide based catalyst are improved, and the catalytic efficiency of the hydrogen evolution reaction is further improved.

The invention discloses a platinum-nickel loaded molybdenum carbide / molybdenum dioxide nano composite material and a preparation method and application thereof.The platinum-nickel loaded molybdenum carbide / molybdenum dioxide nano composite material is prepared by the steps that firstly, metal molybdenum salt and a coordination agent serve as raw materials, a Mo2C / MoO2 substrate material containing heterojunctions is prepared, then PtNi is loaded on the Mo2C / MoO2 substrate material, and the platinum-nickel loaded molybdenum carbide / molybdenum dioxide nano composite material is prepared. Wherein the PtNi alloy is well anchored by the MoO2 / Mo2C nano material carrier, the catalytic stability of the material is further improved, and the reactivity of active sites can be enhanced by the electron coupling and interface synergistic effect provided by a heterogeneous interface, so that the catalytic performance of the material can be developed to the greatest extent; meanwhile, the application cost of hydrogen production under the acidic condition is further reduced. Experimental results show that the platinum-nickel loaded molybdenum carbide / molybdenum dioxide nano composite material has the advantages of high catalytic activity, excellent stability and the like when being used as a hydrogen production electrocatalyst of an acidic electrolyte, so that the platinum-nickel loaded molybdenum carbide / molybdenum dioxide nano composite material has a wide application prospect.

The invention belongs to the technical field of a preparation method of a multi-component composite catalyst, and discloses a preparation method of a nickel-doped molybdenum carbide composite perovskite catalyst, which comprises the following steps: maintaining a constant high-temperature condition in a single reactor, continuously executing minute-level instantaneous gas phase pulse according to a preset time sequence, according to the method, deposition in-situ instantaneous carbonization of molybdenum-containing species and deposition of nickel-containing species are sequentially completed, and finally rapid cooling is carried out. Separation of process time is utilized to cope with migration and agglomeration trends generated by thermodynamic driving of all solid-phase components at continuous high temperature; the formation of the microstructure of the catalyst is controlled by the time sequence of the gas phase pulse instead of a single temperature field, so that the high dispersion state of the active component can be locked and stored by a dynamic process in a necessary high-temperature reaction environment.

The application belongs to the technical field of catalysts, and relates to a supported molybdenum carbide catalyst, which comprises a carrier and an active component; the carrier is MY molecular sieve, and the active component is molybdenum carbide; M is one or two of Co, Ni and Cu. A preparation method thereof is also disclosed, in which a molybdenum source solution is mixed with MY molecular sieve, dried, calcined, and then carbonized in a reducing mixed gas atmosphere to obtain the supported molybdenum carbide catalyst. The Y molecular sieve has good hydrothermal stability, a typical microporous structure, a large specific surface area, and can better disperse the active substance, so that more active components are exposed on the surface and participate in the reaction, and at the same time, smaller and more dispersed metal particles are obtained, which can effectively avoid the contact between the metal particles and the molybdenum carbide; on the other hand, the metal M is beneficial to H2 activation, improves the H2 dissociation capacity, and is helpful to remove the hydroxyl groups remaining on the surface of the molybdenum carbide during the reaction.

The invention belongs to the technical field of synthesis of 2-methoxy-4-methylphenol, and particularly discloses a bimetallic-based catalyst for synthesizing 2-methoxy-4-methylphenol through vanillin hydrogenation as well as a preparation method and application of the bimetallic-based catalyst. Molybdenum carbide (alpha-MoC) is adopted as a carrier, cobalt and iron are loaded by an impregnation method to obtain the bimetallic-based catalyst, and the bimetallic catalyst can be used for obtaining a 2-methoxy-4-methylphenol product with high added value at high yield by taking vanillin as a raw material under mild reaction conditions. The method is short in synthesis process, low in cost, economical, effective, high in universality, environment-friendly, free of corrosion to equipment and high in product quality. The bimetallic-based catalyst not only has excellent catalytic hydrodeoxygenation performance on vanillin, but also has relatively high selectivity on 2-methoxy-4-methylphenol, and in addition, the bimetallic-based catalyst also has excellent cycle stability, wide market prospect and remarkable economic potential.

The invention provides a method for generating molybdenum dioxide or molybdenum carbide through reduction of molybdenum trioxide and application, and the method comprises the following steps: dispersing MoO3 powder in a mixed solution of monohydric alcohol and polyhydric alcohol, adding a triblock copolymer P123 stabilizer, carrying out microwave-assisted solvothermal reaction on the obtained suspension, centrifuging or filtering and washing to obtain molybdenum dioxide or molybdenum carbide; the obtained brown H0. 93MoO3 / C precursor microspheres are placed in an argon plasma environment, high-temperature calcination is carried out at the temperature of 500-600 DEG C for 30-60 min, and brown black MoO2 / C microspheres are obtained; or placing the H0. 93MoO3 / C precursor in a hydrogen-argon plasma environment, and calcining the H0. 93MoO3 / C precursor at a high temperature of 500-600 DEG C for 30-60 minutes to obtain the gray Mo2C / C microspheres. The MoO2 / C and Mo2C / C materials prepared in the invention have nanocrystalline characteristics and excellent electrochemical performance, and have good commercial application prospects as lithium battery negative electrode materials.

A reflective photomask blank has a substrate 10; and a multilayer reflective film 50. The multilayer reflective film 50 has a periodic stacked structure in which a low refractive index layer 30 containing ruthenium (Ru), a high refractive index layer 20 containing silicon (Si), and a diffusion prevention layer 40. The diffusion prevention layer 40 is formed in contact with the low refractive index layer 30 on both or one of a side of the low refractive index layer 30 close to the substrate 10 and a side of the low refractive index layer 30 away from the substrate 10. The diffusion prevention layer 40 is one or more sublayers selected from a layer containing a silicon nitride (SiN), a layer containing silicon carbide (SiC), a layer containing molybdenum (Mo), a layer containing a molybdenum nitride (MoN), and a layer containing molybdenum carbide (MoC).

The invention provides a nitrogen-doped carbon nanosphere-molybdenum carbide-carbon nanotube composite material and a preparation method and application thereof in hydrogen evolution by electrolysis of water, the preparation method comprises the following steps: combining phosphomolybdic acid with dopamine through interaction, grinding with melamine to fully mix, and finally calcining in one step to obtain the nitrogen-doped carbon nanosphere-molybdenum carbide-carbon nanotube composite material. The nitrogen-doped carbon nanosphere-molybdenum carbide-carbon nanotube composite material is prepared by the following steps of: carbonizing polydopamine and melamine and doping nitrogen and molybdenum, catalyzing molybdenum to generate a carbon nanotube, and finally obtaining the nitrogen-doped carbon nanosphere-molybdenum carbide-carbon nanotube composite material, and applying the nitrogen-doped carbon nanosphere-molybdenum carbide-carbon nanotube composite material to the catalytic research of hydrogen evolution reaction by electrolysis of water. Compared with the traditional preparation method, the method disclosed by the invention is simple, rapid, mild in reaction condition and high in yield, and the prepared composite material is uniform in morphology and has excellent electro-catalytic performance on a water electrolysis hydrogen evolution reaction.

The invention relates to a molybdenum carbide-based catalyst for hydrogen production by methanol reforming and a preparation method and application thereof, the molybdenum carbide-based catalyst is CCu / MoC, Cu / MoO3 is used as a precursor, and activated carbon is doped to prepare the molybdenum carbide-based catalyst; in the molybdenum carbide-based catalyst, a metal component Cu loaded on alpha-MoC is a main active component; the preparation method comprises the following steps: roasting molybdenum metal oxide to obtain MoO3; adding a copper metal compound into MoO3, grinding, further drying, and roasting to obtain a Cu / MoO3 catalyst precursor; and uniformly mixing the Cu / MoO3 catalyst precursor with the modified activated carbon, reducing, carbonizing and passivating to obtain a CCu / MoC catalyst, namely the molybdenum carbide-based catalyst. Compared with the prior art, the preparation method has the advantages that the formation of an alpha-MoC crystal phase in the carbonization process of the molybdenum carbide-based catalyst can be effectively promoted, and the dispersion degree of active components on the surface of the carrier is greatly improved, so that the catalyst has good low-temperature activity and hydrogen production efficiency, and meanwhile, the catalyst also has good stability and relatively low CO selectivity.

The application discloses a biomass-based nitrogen-doped carbon-carbide molybdenum composite catalyst and a preparation method and application thereof, and is characterized in that: a widely-sourced biomass, especially agricultural biomass waste, is used as a carbon and nitrogen source, ammonium molybdate is used as a molybdenum source, and a nitrogen-doped carbon-carbide molybdenum composite catalyst is prepared through one-step pyrolysis under an ammonia atmosphere; the catalyst is mesoporous nitrogen-doped carbon loaded with pure beta-phase carbide molybdenum, has the characteristics of a large pore size, high dispersion of beta-phase carbide molybdenum and the like, and has good thermal stability; the catalyst can efficiently denitrogenate quinoline and directively convert the quinoline, and high-selectivity aromatic hydrocarbon products can be obtained; the conversion rate is not less than 99%, the denitrogenation rate is not less than 99%, the selectivity of aromatic compounds is not less than 86%, and the catalyst has the characteristics of low hydrogen consumption due to the avoidance of hydrogen saturation reaction.

The invention belongs to the technical field of catalysts, and relates to a supported molybdenum carbide catalyst, which comprises a carrier and an active component, the carrier is an MY molecular sieve, and the active component is molybdenum carbide; and M is one or two of Co, Ni and Cu. The preparation method comprises the following steps: mixing a molybdenum source solution with the MY molecular sieve, drying, calcining, and carbonizing in a reducing mixed gas atmosphere to obtain the supported molybdenum carbide catalyst. The Y molecular sieve is good in hydrothermal stability, has a typical microporous structure, is relatively large in specific surface area, and can well disperse active substances, so that more active components are exposed on the surface and participate in the reaction, meanwhile, relatively small and relatively dispersed metal particles are obtained, and the metal particles can be effectively prevented from being in contact with molybdenum carbide; and on the other hand, the metal M is beneficial to H2 activation, the dissociation capacity of H2 is improved, and hydroxyl remaining on the surface of molybdenum carbide in the reaction process can be removed.

The invention discloses laminated Ti (C, N)-based metal ceramic and a preparation method thereof, and relates to the field of powder metallurgy, the preparation method comprises the following steps: S1, mixing titanium carbonitride, tungsten carbide, cobalt, molybdenum carbide, hard alloy balls and absolute ethyl alcohol, and drying to obtain a mixture A; mixing titanium carbonitride, tungsten carbide, cobalt, molybdenum carbide, multi-walled carbon nanotubes, hard alloy balls and absolute ethyl alcohol, and drying to obtain a mixture B; s2, adding the mixture A and the mixture B into a mold layer by layer to obtain an A-B-A three-layer mixture, and performing spark plasma sintering to obtain laminated Ti (C, N)-based metal ceramic; spark plasma sintering is carried out under the vacuum condition, the heating rate is 50-75 DEG C / min, the temperature is increased to 1350-1500 DEG C for heat preservation sintering, the heating current during heat preservation sintering is 1700-2000 A, the sintering pressure is 25-40 Mpa, and the heat preservation sintering time is 8-20 min. The surface of the Ti (C, N)-based metal ceramic prepared through the method has high hardness so that high-speed cutting can be facilitated, and the core has high toughness.

The invention relates to the technical field of ceramic materials, in particular to a zirconia ceramic material and a preparation method thereof.The preparation method of the zirconia ceramic material comprises the following steps that firstly, zirconia, modified boron-doped molybdenum carbide, carbon nanotubes, cerium oxide, a dispersing agent and an ethanol water solution are mixed and stirred, and a mixed solution is obtained; carrying out ball milling on the mixed solution to obtain a ball-milled mixed solution; step 2, carrying out slip casting on the ball-milled mixed solution to obtain a wet blank, and carrying out compression molding on the wet blank by using a hydraulic machine to obtain a green body; step 3, cutting the green body to obtain a zirconia ceramic green body; and step 4, sintering the zirconium oxide ceramic green body to obtain the zirconium oxide ceramic material. The preparation method is simple and low in cost, and the prepared zirconia ceramic material has good mechanical performance, compact structure and good wear resistance.

The invention belongs to the field of catalyst preparation, and particularly discloses a method for preparing carbon-coated molybdenum phosphide, which comprises the following steps: by using molybdenum carbide as a framework and a template, replacing carbon atoms in the molybdenum carbide through phosphorization reaction to obtain the molybdenum phosphide. The in-situ replacement mode belongs to a non-destructive replacement reaction, the original morphology and structure of molybdenum carbide can be kept, and meanwhile, part of the replaced carbon is deposited on the surface of molybdenum phosphide to form an in-situ carbon layer which is tightly coated on the surface of molybdenum phosphide. According to the in-situ replacement method provided by the invention, the preparation difficulty of the carbon-coated molybdenum phosphide can be greatly reduced, and the preparation which is short in period, simple, convenient and easy to industrialize is realized.

The invention provides a preparation method and application of a polycrystalline molybdenum carbide / cadmium sulfide composite catalyst. The material has excellent performance in the aspect of hydrogen production by photocatalytic decomposition of water. The preparation method comprises the following steps: firstly, taking melamine, cyanuric acid and ammonium molybdate as raw materials, and annealing in an inert atmosphere in a tubular furnace to prepare polycrystalline molybdenum carbide; then taking cadmium nitrate, thiourea and ethidene diamine as raw materials to hydrothermally prepare cadmium sulfide in a polytetrafluoroethylene high-pressure reaction kettle; and finally, dispersing the polycrystalline molybdenum carbide and cadmium sulfide in N, N-dimethylformamide, and carrying out ultrasonic treatment, stirring, washing and drying to obtain the polycrystalline molybdenum carbide / cadmium sulfide. According to the polycrystalline heterostructure disclosed by the invention, a channel for directionally and rapidly transferring current carriers is constructed, the separation of electron-hole pairs is accelerated, and the migration rate of electrons is improved; meanwhile, a molybdenum vacancy located at a crystal boundary forms a Lewis acid site serving as an active site of a hydrogen production reaction, so that an energy barrier of the hydrogen production reaction is reduced, and excellent performance of photocatalytic decomposition of water to produce hydrogen is shown.