57 results about "Ammonium heptamolybdate" patented technology

The invention provides a preparation method of a shape-controllable iron-molybdenum formaldehyde catalyst, and belongs to the technical field of catalyst preparation. The preparation method of the catalyst comprises the following steps: firstly, respectively mixing ammonium heptamolybdate tetrahydrate, ferric nitrate nonahydrate and a complexing agent, and dissolving in water to prepare a molybdenum-containing solution and an iron-containing solution; then mixing the molybdenum-containing solution and the iron-containing solution, adjusting the pH value, carrying out vacuum rotary evaporation to form sol, finally drying the sol to form xerogel, and roasting the xerogel to obtain a catalyst finished product. The coordination environment of Mo and Fe in the precursor solution is regulated and controlled through the complexing agent, uneven distribution of components is prevented, the uniform precursor solution is formed, the morphology and particle size of the catalyst are influenced by adjusting the pH of the solution and changing the precipitation rate of the precursor and the growth process of particles, and the catalyst with different morphologies and excellent comprehensive performance is prepared.

The present invention provides a method, application and product for preparing diglyceride with weight loss effect by enzymolysis, which belongs to the field of enzyme engineering technology. The method comprises the following steps: S1, mixing lipase, ammonium heptamolybdate tetrahydrate with water, adding glycerol precipitation, filtering, and obtaining an enzyme preparation; S2, mixing plant raw material oil, glycerol, fatty acid, sodium fatty acid with the enzyme preparation obtained in step S1, reacting under inert gas conditions, and obtaining an enzymolysate; S3, molecularly distilling the enzymolysate obtained in step S2 to obtain diglyceride; wherein the lipase is a mixture of Rhizomucor miehei lipase and Candida antarctica Aspergillus niger lipase. The present invention uses ammonium heptamolybdate tetrahydrate to load a specific lipase mixture, and at the same time optimizes the component types and ratios of the raw materials in the enzymolysis process, effectively improving the mass percentage content and diglyceride yield of enzymolysis production of diglyceride.

The invention discloses a preparation method and application of a composite hydrogen evolution catalyst for in-situ growth of MoS2 on a Ti3C2Tx ultrathin nanosheet, relates to a preparation method and application of a hydrogen evolution catalyst, and aims to solve the technical problems of low utilization rate of active sites and low catalytic efficiency of the conventional MoS2 catalyst. The method comprises the following steps: etching titanium aluminum carbide to obtain Ti < 3 > C < 2 > F < x > powder; stripping the powder or performing alkali heat treatment, vulcanization or hydro-thermal treatment after stripping to prepare an ultrathin nanosheet; the ultrathin nanosheets and a mixed solution of ammonium heptamolybdate tetrahydrate and thiourea are subjected to a hydrothermal reaction, separation, washing and drying are carried out, the composite hydrogen evolution catalyst MoS2 / Ti3C2Tx is obtained, and T is F, S, O or OH. When the composite material is used for producing hydrogen by electrolyzing water, the current density of 10mA. Cm <-2 > can be realized only by virtue of 86-97mV overpotential in alkaline electrolyte, and the composite material is used in the field of producing hydrogen by electrolyzing alkaline water.

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 present invention provides a preparation method and application of a sulfur-containing molybdenum phosphide catalyst for the hydrogenation of medium- and low-temperature coal tar. The method uses ammonium heptamolybdate as a molybdenum source, diammonium hydrogen phosphate as a phosphorus source, and silicon-surface-modified alumina as a carrier. After equal volume impregnation and drying and calcination, the catalyst is first sulfurized and then hydrogenated in a fixed-bed reactor to reduce the severity of the activation process of the molybdenum phosphide and simultaneously form a sulfur-doped molybdenum phosphide active structure to obtain a sulfur-containing molybdenum phosphide catalyst. Medium- and low-temperature coal tar is then directly introduced into the original fixed-bed reactor to carry out a medium- and low-temperature coal tar full-fraction hydrogenation refining reaction. The preparation of the sulfur-containing molybdenum phosphide catalyst and the in-situ activation in the reactor of the present invention can be completed completely within the preparation and reaction system of the existing transition metal sulfide catalyst, greatly reducing the difficulty of preparing and using the phosphating catalyst. Moreover, the sulfur-containing molybdenum phosphide catalyst prepared by the present invention can be used completely based on the existing hydrogenation system and exhibits good hydrogenation activity.

The invention relates to a method for producing ammonium heptamolybdate with high crystal yield and high purity by taking ammonium tetramolybdate as a raw material, which comprises the following steps: adding pure water into a batching tank at room temperature, starting a stirrer, introducing liquid ammonia into the batching tank, then adding ammonium tetramolybdate, stirring and dissolving, heating to 65 DEG C, and stirring and dissolving for 1 hour at the constant temperature of 65-70 DEG C to obtain an ammonium molybdate mixed solution; refluxing, circulating and precisely filtering by a precise filter, pumping into a cooling crystallizing tank, adding nitric acid into the crystallizing tank while stirring at room temperature to adjust the pH value of the solution to 6.2-6.5, and continuously stirring for 30 minutes; and cooling the ammonium molybdate mixed solution in the cooling crystallization tank for 7 hours, cooling the temperature of the material in the crystallization tank to 10-12 DEG C, crystallizing and separating out an ammonium heptamolybdate product, centrifugally filtering, introducing air with the relative humidity of 40% and the temperature of 15-25 DEG C into a rotary roller dryer, and drying to obtain the ammonium heptamolybdate. The method has the advantages of simple and reasonable process, regular product crystal form, good crystallization yield and high purity.

The application discloses a preparation method of a nanoscale multi-metal catalyst, which comprises the following steps: mixing ferric nitrate, magnesium nitrate, lanthanum nitrate, gadolinium nitrate, ammonium heptamolybdate and citric acid with water to obtain a concentrated solution by heating and concentrating; mixing ethylenediaminetetraacetic acid, ammonia water and urea to obtain an ethylenediaminetetraacetic acid solution; mixing the concentrated solution and the ethylenediaminetetraacetic acid solution to obtain a mixed solution by stirring, adding a surfactant into the mixed solution and calcining, and finally roasting. The ferric nitrate, the magnesium nitrate, the lanthanum nitrate and the gadolinium nitrate are mixed, a complexing agent is added, a solution is prepared by using a complexing method, the solution is concentrated, calcined and sieved, and finally the nanoscale multi-metal catalyst is formed. The catalyst prepared by the method has a uniform particle size. The catalyst prepared by the method is combined with a plasma technology to prepare a single-walled carbon nanotube, and the single-walled carbon nanotube (without treatment) has a high ratio, a large IG / ID and a small powder resistance.

The application discloses a kind of low-temperature denitration catalysts of water resistance, sulfur resistance and alkali resistance and a preparation method thereof, and belongs to the technical field of catalyst materials.The preparation method comprises the following steps: ammonium metavanadate and ammonium dihydrogen phosphate are added to monoethanolamine and a small amount of water to stir and dissolve, obtaining solution 1; cerium nitrate is added to deionized water to dissolve, obtaining solution 2; solutions 1 and 2 are mixed uniformly to obtain solution 3; ammonium metatungstate and ammonium heptamolybdate are added to deionized water to dissolve and then added to solution 3, obtaining solution 4; titanium white, zirconium nitrate and silicon dioxide powder are mixed uniformly and added to solution 4 to stir uniformly, while a certain amount of lactic acid, glass fiber and boric acid are added, obtaining uniform slurry; drying; calcination, and the process is completed.The beneficial effects are as follows: the prepared catalyst can achieve a denitration efficiency of more than 90% in a low-temperature range of 160-220°C, and the catalyst has high strength, resistance to 6% water poisoning, 3% alkali poisoning and 400ppm sulfur poisoning.

The application belongs to the technical field of atmosphere treatment, and provides a sulfur-poisoning-resistant denitration and carbon monoxide removal SCR catalyst and a preparation method thereof. Part of anatase titanium white, platinum nitrate, ammonium metatungstate and water are first mixed to perform first calcination to obtain a precursor powder; the rest of the anatase titanium white, clay, stearic acid, ammonium heptamolybdate, ammonium metavanadate, glass fiber, cerous nitrate, zirconium nitrate and water are second mixed to obtain a slurry; the slurry, the precursor powder, carboxymethyl cellulose ammonia and polyoxyethylene are mixed, and after the pH value is adjusted to be alkaline, kneading and aging are sequentially performed to obtain an aged slurry; the aged slurry is sequentially subjected to extrusion molding, drying and second calcination to obtain the SCR catalyst. The obtained SCR catalyst can efficiently remove nitrogen oxides and carbon monoxide, and also has excellent sulfur-poisoning resistance.

The present invention relates to a polyacid-based cobalt-containing magnetic compound, the molecular formula of which is [Co(C 20 H 14 N4)2]2(Mo8O 26 )·Solv, during preparation, ammonium heptamolybdate is dissolved in distilled water, the pH of the solution is adjusted and then placed at the bottom of a test tube; a mixed solution of distilled water and acetonitrile is added as a transition layer, and the upper layer is a solution in which cobalt chloride and 4'-(4-pyridyl)-2,2':6',2"-terpyridine are dissolved; the solution is allowed to stand and slowly diffuse to obtain red block crystals, thereby obtaining a polyacid-based cobalt-containing magnetic compound; the pH value of the ammonium heptamolybdate solution is adjusted to 4.1, and the volume ratio of distilled water and acetonitrile in the transition layer is 1:1; the polyacid-based cobalt-containing magnetic compound of the present invention is synthesized by a layered diffusion method, using a molybdate solution as a lower layer, a magnetic center cobalt ion and an organic ligand as an upper layer, and then using a mixed solvent as an intermediate layer to obtain a compound to obtain a single crystal sample.

The application provides a molybdenum-copper composite coiled material for a heat sink and a preparation method thereof, and relates to the technical field of molybdenum-copper composite heat sink materials. The method adopts ammonium heptamolybdate for heat preservation in three temperature zones, which is beneficial to the growth of molybdenum trioxide, and generates coarse and loose molybdenum trioxide; the coarse and loose molybdenum trioxide is reduced to obtain very fine molybdenum powder; the ultra-fine molybdenum powder is mixed with a copper-containing solution to obtain a solid-liquid mixture, and then the solid-liquid mixture is reduced in hydrogen to obtain uniform molybdenum-copper powder, so that the material organization is more uniform; and the ultra-fine molybdenum powder is easier to sinter due to the larger surface activity, and can be sintered to be dense at a lower sintering temperature; the application also adopts polyformaldehyde, polyethylene, styrene-butadiene-styrene and other high molecular organic substances as binders, so that the obtained heat sink material has better fluidity when being pressed into a shape, is easy to be removed in the debinding stage, and almost has no residue, and can obtain molybdenum-copper heat sink material with better size precision and better density.

The invention discloses a preparation method of an iron-molybdenum hydrogenation catalyst for coke-oven gas hydrogenation fine desulfurization, and particularly relates to the technical field of preparation of a catalyst for coal chemical gas purification. The invention aims to solve the core problem that the service life of the existing catalyst is only 3-5 months due to micropore blockage caused by tar carbonization in coal gas. The catalyst takes basic oxide modified gamma-Al2O3 as a carrier (neutralizing the strong acidity of traditional aluminum oxide and inhibiting tar adsorption), active components are precursor ferric nitrate, precursor ammonium heptamolybdate and an anti-carbon deposition component (CeO2 or ZrO2), and tartaric acid of which the dispersity is superior to that of citric acid is adopted as a competitive adsorption aid; in the preparation process, the beta acid site strength is reduced through segmented roasting at the high temperature of 600-700 DEG C, and carbon deposition generation sites are reduced; accurate prevulcanization is adopted, so that the structural stability of the catalyst is further optimized. The organic sulfur conversion rate of the catalyst is greater than or equal to 97.5%, the continuous operation life is prolonged to 12-18 months, the catalyst can be efficiently used for pretreatment of raw material gases such as preparation of methanol from coke-oven gas, synthesis ammonia and the like, and deep removal of organic sulfur and long-acting operation of the catalyst are realized.

The application belongs to the technical field of electrochemical bifunctional overall water splitting catalyst materials, and particularly relates to a bifunctional boron-doped molybdenum-cobalt microsphere overall water splitting catalyst as well as a preparation method and application thereof. ‑2 The application is prepared by dissolving ammonium heptamolybdate and cobalt acetate tetrahydrate in water in a small amount of sulfuric acid and sodium citrate borate system according to a certain molar ratio, heating to a transparent liquid at a constant temperature, taking foamed nickel as a working electrode, taking a platinum sheet and an Ag / AgCl electrode as a counter electrode and a reference electrode, and taking a current density of-300 to-200 mA cm ‑2 at 20-50 DEG C for 10-30 minutes, rinsing the surface of the foamed nickel with deionized water after the electrodeposition is completed, and vacuum drying to obtain a black microsphere boron-doped MoCo material loaded on the foamed nickel. The catalyst prepared by the application has the characteristics of low cost, non-toxicity, high chemical activity and stability, exhibits high hydrogen evolution and oxygen evolution activity, and low overpotential.

The invention provides a cathode material, a proton ceramic reactor, preparation and application in ammonia synthesis, and the cathode material and the proton ceramic reactor are prepared by the following steps: dissolving raw materials in distilled water under heating and stirring conditions to form a solution; the raw materials comprise strontium nitrate, ferrous nitrate nonahydrate, ammonium heptamolybdate tetrahydrate, ruthenium nitrosyl nitrate, citric acid and glycine; then adjusting the pH value of the solution to 7 + / -0.5 to promote the formation of a complex, and maintaining a heating and stirring state to gradually evaporate water to obtain a gel; and drying and calcining to obtain the cathode material Sr2Fe1. 5Mo0.5-xRuxO6-delta, x is more than 0 and less than 0.1, and delta is the oxygen vacancy content. When the cathode material is applied to a proton ceramic reactor, the catalytic activity of the cathode of the reactor can be remarkably improved, and efficient nitrogen reduction reaction ammonia synthesis under the medium-temperature condition suitable for industrial application is realized.

This invention discloses a method for preparing a catalyst for the oxidative dehydrogenation of ethane, comprising the following steps: dissolving ammonium heptamolybdate tetrahydrate, ammonium metavanadate, telluric acid, and a dispersant in deionized water to form a mixed solution; adding an aqueous solution of niobium oxalate to the mixed solution within 15–50 min to form a suspension; then adding an aqueous solution of the template agent polyether P123; and subjecting the process to aging, hydrothermal crystallization, drying, calcination, and removal of the M2 phase to obtain the catalyst for the oxidative dehydrogenation of ethane. This invention introduces a dispersant and the template agent polyether P123 at specific steps in the catalyst preparation process, combined with limiting the time of adding the niobium oxalate aqueous solution to the mixed solution, which effectively improves the pore structure and specific surface area of ​​the catalyst, increases the proportion of high-concentration active sites on its terminal surface, and thus significantly enhances the catalyst's reactivity.

The invention provides a method for preparing fine-grained ammonium heptamolybdate crystals by an aid crystallization method. The method specifically comprises the following steps: step 1, preparing an ammonium molybdate solution; 2, crystallizing an ammonium molybdate solution auxiliary agent; and step 3, performing reduced pressure evaporation to prepare fine-fraction ammonium heptamolybdate crystals. Molybdenum oxide is used as a raw material, ammonium heptamolybdate is formed under the synergistic effect of induced crystallization of assistant crystallization and reduced pressure evaporation, and the concentration of molybdenum in the solution is improved through reduced pressure evaporation, so that molybdate ions are induced to be converted towards a high polymerization degree direction, and formation of ammonium heptamolybdate is remarkably promoted; and the crystallization auxiliary agent can promote the formation of crystals and refine ammonium heptamolybdate crystal particles, so that a fine-fraction ammonium heptamolybdate crystal product with high purity and narrow particle size distribution is obtained.

The invention relates to the technical field of energy materials and electro-catalysis, in particular to a preparation method and application of a catalyst containing bimetallic oxide and transition metal sulfide.The preparation method comprises the steps that firstly, thiourea, ammonium heptamolybdate and cobalt nitrate are sequentially mixed with ionized water, and ultrasonic treatment is conducted to prepare a uniform mixed solution; and then putting the mixed solution and a current collector into a tetrafluoroethylene lining together for hydrothermal reaction, and after the reaction is completed and natural cooling is performed, washing and vacuum drying are performed to obtain the alkaline electrolytic water oxygen evolution reaction catalyst containing the bimetallic oxide and the transition metal sulfide. The catalyst prepared by the invention shows relatively good stability and catalytic property in alkaline electrolyte, and relatively high current density can be obtained under relatively low overpotential. Meanwhile, the preparation method is simple to operate, short in time consumption, low in production cost and easy to realize large-scale production, and has an excellent application prospect in the field of electro-catalysis.

The application provides a preparation method of a morphology-controllable iron-molybdenum formaldehyde catalyst, and belongs to the technical field of catalyst preparation.The preparation method of the catalyst comprises the following steps: firstly, ammonium heptamolybdate tetrahydrate and ferric nitrate nonahydrate are respectively mixed with a complexing agent to prepare a molybdenum-containing solution and an iron-containing solution; then the molybdenum-containing solution and the iron-containing solution are mixed, pH is adjusted, vacuum rotary evaporation is carried out to form a sol, and finally, the sol is dried to form a dry gel, and the dry gel is calcined to obtain a catalyst product.The Mo and Fe coordination environment in the precursor solution is regulated by the complexing agent in the application, the component distribution is prevented from being uneven, a uniform precursor solution is formed, the precipitation rate of the precursor and the particle growth process are changed by adjusting the pH of the solution, the morphology and particle size of the catalyst are influenced, and a catalyst with different morphology and excellent comprehensive performance is prepared.

The application discloses a kind of high-strength flat plate catalyst and preparation method thereof, it is related to catalyst technical field.The technical scheme is as follows: including the following mass fraction components: titanium dioxide 50-80 parts, high-viscosity kaolin 2-15 parts, glass fiber 2-10 parts, carbon fiber 2-10 parts, plasticizer 2-15 parts, ammonium heptamolybdate 0.5-2 parts, ammonium metavanadate 0.5-2 parts and water 10-30 parts.The high-viscosity kaolin is prepared, and then combined with the subsequent high-temperature coating process, the adhesion between the catalyst mud and the stainless steel screen plate is greatly improved, thereby enhancing the stability of the catalyst, prolonging the service life of the catalyst and improving the catalytic reaction efficiency.

The patent discloses a preparation method of Mo-V-Sb-Na-O composite oxide catalyst and application of the Mo-V-Sb-Na-O composite oxide catalyst in a reaction of preparing acrylic acid from propylene aldehyde, and comprises the following steps: using a solvent evaporation method to prepare a Mo-V series catalyst, dissolving ammonium heptamolybdate, ammonium metavanadate and antimony trioxide in deionized water and uniformly mixing under rapid stirring, and drying and calcining the mixed liquid to obtain a high-activity catalyst for selectively oxidizing propylene aldehyde into acrylic acid, i.e. a composite oxide catalyst. The composite oxide catalyst prepared by the above method has the advantages of simple operation process, short preparation time, good selectivity and yield of acrylic acid.

The present invention belongs to the field of catalyst technology and provides a vanadium-based catalyst, a preparation method thereof, and its application in the preparation of homogenized anhydrides. The method comprises the following steps: mixing vanadium pentoxide, phosphoric acid, rubidium nitrate, oxalic acid, and water to obtain an active component slurry A; mixing titanyl sulfate, lanthanum nitrate, rubidium nitrate, ammonia water, and water, and calcining to obtain a composite oxide; mixing ammonium metavanadate, ammonium heptamolybdate, the composite oxide, oxalic acid, and water to obtain an active component slurry B; spraying the active component slurries A and B onto a support in sequence and calcining to obtain a vanadium-based catalyst. By selecting specific types and contents of active components, arranging the active components in a double layer, and preparing the composite oxide as a support within the outer layer of the active components, the activity and stability of the catalyst are improved, thereby increasing the yield of homogenized anhydrides. When the vanadium-based catalyst prepared by the present invention is applied to the preparation of homogenized anhydrides, the homogenized anhydride yield reaches as high as 112.7 wt%.

The present application relates to the technical fields of energy materials and electrocatalysis, and particularly relates to a preparation method and application of a catalyst containing bimetallic oxide and transition metal sulfide, which comprises the following steps: firstly, mixing thiocarbamide, ammonium heptamolybdate and cobalt nitrate with ionized water in sequence, and preparing a uniform mixed solution by ultrasonic; then, putting the mixed solution and a current collector into a tetrafluoroethylene lining for hydrothermal reaction; after the reaction is completed and naturally cooled, washing, vacuum drying, and then the catalyst for alkaline electrolytic water oxygen evolution reaction containing bimetallic oxide and transition metal sulfide can be obtained. The catalyst prepared by the present application exhibits good stability and catalytic property in the alkaline electrolyte, and can obtain a higher current density at a lower overpotential. Meanwhile, the preparation method of the present application is simple in operation, short in time consumption, low in production cost, easy to realize large-scale production, and has excellent application prospect in the field of electrocatalysis.

The invention belongs to the field of powder metallurgy, and particularly discloses a method for preparing nano molybdenum-rhenium alloy powder through liquid-phase in-situ precipitation. According to the method, ammonium heptamolybdate and ammonium perrhenate serve as raw materials and are dissolved in an ammonia water solvent, then a dispersing agent, a complexing agent and a surface active agent are added, the pH is adjusted to be within the acidic range, so that molybdenum-rhenium precursors are rapidly separated out from the solution in situ, and atomic-scale mixed ammonium dimolybdate-ammonium perrhenate mixed crystals are formed. And then low-temperature calcination dehydration is conducted in the argon atmosphere, gradual reduction and alloying of oxides are sequentially achieved through a three-stage hydrogen reduction technology, and finally the nanometer molybdenum-rhenium alloy powder which is uniform in component, good in dispersity and about 160 nm in average particle size is obtained. The method is simple in process, and the prepared powder is small in particle size and concentrated in distribution, has high sintering activity and is suitable for preparing a high-performance molybdenum-rhenium alloy material.

The current invention describes the synthesis of heterogeneous composite comprising laponite and heptamolybdate by wetness impregnation method. Different experimental settings were used to carry out the synthesis, including the heptamolybdate ammonium dose (1.5, 1 or 0.5 g), ion exchanger dose tetrabutyl ammonium bromide (0.5, 0.25 or 0.125g), reaction duration (12 or 24h) and calcination temperature (200, 300 and 400 °C) for 2 hours. The optimal synthesis composition of the laponite / molybdate (Lap-Mo) is as follows: 5 g of Lap + 0.5 g of TBA + 1.5 g of heptamolybdate ammonium with reaction duration of 24 h and a calcination temperature of 300 °C for 2 hours under air. The laponite / molybdate composite have been used in an AOP to degrade MB dye in presence of H2O2 as an oxidant under visible light radiation. The AOP experiment have been optimized using RSM based on BBD. Under the optimum conditions: contact time=72 min, [H2O2 / Lap-Mo] wt% ratio= 1.24, dye concentration= 20.95 mg.L-1 pH= 8.3 reaching a 99% of degradation rate. The Lap-Mo catalyst degradation efficiency was also tested for other dyes such as safranin T (ST) and rhodamine B (RhB) as cationic dyes and methyl orange (MO) as anionic dye. Indeed, they exhibits a highly degradation rate equal to 96, 90 and 89% for ST, RhB and MO, respectively. Advantageously, the invention intends to promote, profitably, and efficiently dye degradation using the laponite / molybdate composite. Furthermore, the potential of the invention falls within the framework of improving wastewater treatment and paves the way to more areas of application in multiple industries.

The invention provides a method for preparing ammonium dimolybdate from ammonium heptamolybdate, and belongs to the technical field of chemical product preparation. The method comprises the following steps: weighing ammonium heptamolybdate and an ammonium source in a container according to a molar ratio, adding deionized water, stirring while heating until solids are completely dissolved, then cooling and crystallizing the solution, filtering after the crystallization is finished, and drying the filtered crystal substance to obtain ammonium dimolybdate; the ammonium source is one or more of ammonium bicarbonate, ammonium carbonate and ammonia water, and the molar ratio of the ammonium heptamolybdate to the ammonium source is equal to 1: (1.0-1.3) in terms of total ammonium in the ammonium heptamolybdate and the ammonium source. The method is short in technological process, low in energy consumption and relatively simple in preparation means, and the prepared ammonium dimolybdate product is low in impurity content and stable in quality.

The present invention relates to the technical field of photocatalytic materials, and particularly relates to a MoC quantum dot / zinc indium sulfide composite photocatalyst with lattice strain, and a preparation method and application thereof. The preparation method comprises the following steps: Step 1, preparation of MoC quantum dots with lattice strain: Melamine and ammonium heptamolybdate are dissolved in methanol and deionized water; the ammonium heptamolybdate solution is added dropwise to the vigorously stirred melamine suspension, and the mixture is evaporated to dryness by water bath; the white precipitate is reacted at 700 °C for 1-3 hours; Step 2, in-situ growth and compounding of the MoC quantum dots and zinc indium sulfide to obtain the composite photocatalyst. The present invention realizes the controllable preparation of MoC quantum dots with different lattice strains, which helps to improve the energy level structure of the nanomaterials, thereby affecting the charge transfer efficiency. Moreover, the preparation process does not involve dangerous chemicals, the preparation is safe, the raw materials are cheap and easily available, and the cost is low. Under simulated sunlight, the composite photocatalyst can stably and continuously produce hydrogen for 144 hours.

The invention relates to the technical field of catalyst preparation, and specifically discloses a method for preparing a nanocatalyst for the reduction reaction of p-nitrophenol. The method specifically comprises the following steps: S1, preparation of MoS2: S101, adding 1 mmol of ammonium heptamolybdate and 30 mmol of thiourea to 40 mL of deionized water, and magnetically stirring for 30 minutes; S102, pouring the stirred transparent solution into a stainless steel polytetrafluoroethylene-lined autoclave, and heating at 200 DEG C for 12 hours; S103, centrifuging the obtained sample, washing it with pure water and ethanol, and drying it at 80 DEG C for 8 hours to obtain MoS2; S2, preparation of CoMoS2: S201, adding 1 mmol of a mixture containing ammonium heptamolybdate and cobalt chloride hexahydrate, and 30 mmol of thiourea to 40 mL of deionized water, and magnetically stirring for 30 minutes. In the invention, the synthesized Au / CoMoS2 catalyst exhibits excellent catalytic activity and has a short reaction processing time.

The invention relates to a self-supporting lanthanum-molybdenum-cobalt-boron difunctional complete water splitting catalyst as well as a preparation method and application thereof, and belongs to the technical field of electro-catalytic materials. The method comprises the following steps: dissolving lanthanum salt, ammonium heptamolybdate and cobalt acetate tetrahydrate in an aqueous solution containing boric acid and sodium citrate according to a set molar ratio, adding a small amount of sulfuric acid, and heating to form a uniform electrolyte; and by taking the foamed nickel as a working electrode, carrying out electro-deposition for 100-200 minutes at the current density of-300 to-200mA cm <-2 > and the temperature of 20-50 DEG C to obtain the lanthanum-molybdenum-cobalt-boron material loaded on the foamed nickel. The catalyst has a self-supporting structure, does not need a binder, is simple in preparation process, low in cost and environment-friendly, shows high catalytic activity and excellent stability in both hydrogen evolution reaction and oxygen evolution reaction, and is suitable for an efficient all-water decomposition system.

The present invention discloses a preparation method and application of a denitrification and mercury co-removal SCR honeycomb catalyst, which relates to the technical field of flue gas denitrification. The raw material components of the denitrification catalyst of the present invention include: anatase catalytic titanium dioxide, pseudo-boehmite, ammonium metavanadate-monoethanolamine aqueous solution, ammonium heptamolybdate, ammonium metatungstate, glass fiber, cerium nitrate, copper nitrate, antimony acetate, silica sol, sesbania powder and polyethylene oxide. The denitrification and mercury co-removal SCR catalyst prepared by the present invention has a large specific surface area, good dispersion of active components, strong mercury adsorption and oxidation ability, remarkable denitrification effect, and has a good Hg<supgt;0< / supgt; oxidation rate, and is very suitable for the denitrification and mercury emission control of fixed-source flue gas such as thermal power plants, coking plants, waste incinerators, iron and steel sintering machines, and cement kilns.

The invention belongs to the technical field of hydrometallurgy, and discloses a method for leaching molybdenum from molybdenum calcine, which comprises the following steps: mixing the molybdenum calcine and a solid ammonium source, and heating to obtain a transformed material; then, the transformed material is soaked in water and filtered, and a molybdenum-containing solution A is obtained; the ammonium molybdate is prepared through the technology combining heating transformation with water leaching, active molybdenum oxide in the molybdenum calcine is transformed into ammonium heptamolybdate / ammonium dimolybdate in the transformation process, the situation that local ammonia is excessive in the direct leaching process can be avoided, the leaching rate of MoO3 can be greatly increased, and the method is suitable for industrial production. During leaching, molybdenum enters a solution in a relatively pure ammonium heptamolybdate / ammonium dimolybdate form, so that the introduction of impurities is reduced, the burden of subsequent purification and impurity removal steps is reduced, and the impurity removal cost is reduced; the method is simple in process, does not need to use a large amount of strong acid or strong alkali or other strong-corrosivity reagents, reduces the dosage of the reagents in the leaching and subsequent processes, is wide in raw material source and low in price, is low in production cost, and is beneficial to industrialization and marketization.