13 results about "Ammonium heptamolybdate" patented technology

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.

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 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 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 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 application provides a low-temperature sulfur-resistant denitration catalyst and a preparation method thereof, and the preparation method comprises the following steps: adding titanium dioxide into deionized water under stirring to obtain a base slurry; dissolving ammonium metavanadate in dilute sulfuric acid to react to generate vanadyl sulfate, adjusting the pH value to 2-4, and then standing and aging to obtain a vanadium precursor solution; dissolving ammonium heptamolybdate in deionized water, adding dilute sulfuric acid to adjust the pH value to 2-4, and then obtaining a molybdenum precursor solution; first adding the molybdenum precursor solution into the base slurry, mixing uniformly, then adding the vanadium precursor solution, continuing to stir, then adding an additive, stirring uniformly, and controlling the pH value of the slurry in the mixing process to be in the range of 2-4 to obtain a mixed slurry; and performing spray drying and calcination on the mixed slurry, and obtaining the low-temperature sulfur-resistant denitration catalyst after cooling. The catalyst prepared in the application has the characteristics of high dispersion of active components, high low-temperature denitration efficiency, excellent sulfur resistance and the like under the conditions of low temperature and high-sulfur flue gas.

The invention relates to the technical field of efficient catalysts and prevention and control of atmospheric pollutants, in particular to a wide-temperature denitration catalyst and a preparation method thereof. The preparation method comprises the following steps: adding deionized water and a dispersing agent into a reaction kettle, stirring after heating, then simultaneously injecting a salt solution and a precipitator solution into the reaction kettle, continuously stirring and mixing the solutions after charging, and filtering, washing and drying after aging to obtain precursor powder; calcining the precursor powder in an N2 atmosphere to obtain calcined powder; and putting the calcined powder into a mixed aqueous solution of ammonium metavanadate and ammonium heptamolybdate, carrying out water bath stirring reaction, drying, and calcining to obtain the wide-temperature denitration catalyst. The wide-temperature characteristics of low-temperature efficient denitration and high-temperature stable denitration of the catalyst are achieved through active component dispersion, layered structure regulation and control and high-temperature and low-temperature active site collaborative construction, and the catalyst effectively adapts to the working condition characteristic that the temperature of industrial flue gas fluctuates greatly.

The application discloses a Mo-Ru double-site transition metal catalyst and a preparation method thereof, and belongs to the technical field of electrocatalytic materials. The method uses graphene oxide as a carrier, adds a mixed solution of ruthenium trichloride trihydrate and ammonium heptamolybdate tetrahydrate into a graphene oxide dispersion solution, and performs ultrasonic treatment for 6 hours to obtain a uniform precursor solution; then, a hydrothermal reaction is performed to obtain a solid product; after the product is freeze-dried for 12 hours, a chemical vapor deposition method is used to perform high-temperature nitridation on the product at 800 DEG C under an ammonia-argon mixed atmosphere for 2 hours, and finally, the Mo-Ru double-site transition metal catalyst is prepared. The catalyst exhibits excellent two-electron hydrogen evolution reaction electrocatalytic activity and long-term stability in acidic and alkaline media, and can be efficiently applied to the field of hydrogen production by water electrolysis.

The present invention relates to the technical field of catalysts. Disclosed are a high-strength flat-plate catalyst and a preparation method therefor. The technical solution thereof is the catalyst comprising the following components in parts by mass: 50-80 parts of titanium dioxide, 2-15 parts of high-viscosity kaolin, 2-10 parts of glass fibers, 2-10 parts of carbon fibers, 2-15 parts of a plasticizer, 0.5-2 parts of ammonium heptamolybdate, 0.5-2 parts of ammonium metavanadate, and 10-30 parts of water. In the present invention, the high-viscosity kaolin is prepared, and in combination with the subsequent high-temperature coating process, the adhesive force between a catalyst slurry and a stainless steel screen plate is greatly improved, thereby enhancing the stability of the catalyst, prolonging the service life of the catalyst, and improving the reaction efficiency of the catalytic.

The invention relates to a molybdenum catalyst and a preparation method and application thereof. The method comprises the following steps: by taking ammonium heptamolybdate as a molybdenum source, trithiocyanuric acid as a sulfur source and activated carbon as a carrier, dispersing by ball milling, and calcining and loading in a nitrogen atmosphere to obtain the catalyst with molybdenum disulfide loaded on the activated carbon. The catalyst can be recovered through centrifugation and filtration and has excellent cycle stability. According to the method, a dexlansoprazole by-product (a mixture mainly containing levolansoprazole) is taken as a substrate, under the action of a molybdenum catalyst, hydrogen is introduced as a reducing agent, and the by-product can be reduced into the lansoprazole thioether (a synthetic precursor of dexlansoprazole) in a high-selectivity manner. In addition, racemic lansoprazole can be directly used as a substrate, high-selectivity reduction into lansoprazole thioether (a dexlansoprazole synthesis precursor) can be realized under the action of the same molybdenum catalyst, and the raw material application range of the process is further widened. The method solves the industrial problem that byproducts cannot be efficiently recycled in the existing dexlansoprazole synthesis process, has the advantages of simple reaction process, easiness in product separation and catalyst recyclability, and has a good industrial application prospect.

The invention belongs to the technical field of electro-catalysis and energy materials, and particularly relates to a rare earth element-doped carbon-coated molybdenum phosphide bifunctional catalyst and a preparation method thereof. The method comprises the following steps: 1) screening preparation raw materials, wherein the raw materials comprise rare earth metal salt, ammonium heptamolybdate tetrahydrate, a carbon source and a phosphorus-containing chelating agent; 2) weighing the raw materials obtained in the step 1) in proportion, uniformly mixing in a certain amount of deionized water, and then drying by distillation at the temperature of 60-100 DEG C to obtain a pre-product; and 3) grinding the pre-product obtained in the step 2), and performing pyrolysis treatment at 800-1000 DEG C to obtain the rare earth metal doped carbon coated molybdenum phosphide bifunctional catalyst. The introduction of the phosphorus-containing chelating agent effectively realizes uniform doping of rare earth elements into molybdenum phosphide crystal lattices. Due to introduction of rare earth elements, redistribution of surface charge density of the molybdenum phosphide is realized, the adsorption energy of intermediate adsorbates in the reaction is optimized, and the rare earth elements serve as reaction active sites to further activate the oxygen evolution activity of the molybdenum phosphide.