40results about How to "Avoid sintering and agglomeration" patented technology

The invention provides a catalyst for catalyzing methane combustion and a preparation method thereof. The catalyst comprises a carrier, and an active component which is loaded on the carrier, wherein the active component is wrapped with a wrapping layer for providing oxygen vacancy. The catalyst further comprises a catalyst promotor which is a ceria-zirconia solid solution. According to the catalyst, the wrapping layer wraps the active component, so that oxygen molecule stored in the wrapping layer can be timely conveyed to the active component, so that the high-temperature stability of the active component of the catalyst is maintained; in addition, the catalyst further comprises the catalyst promotor which is the ceria-zirconia solid solution capable of generating more oxygen vacancies and timely effectively storing and discharging oxygen, so that the high-temperature stability of the active component of the catalyst is improved; in addition, the wrapping layer, the ceria-zirconia solid solution and the carrier are mutually dispersed and in contact, so that the mutual insulation effect is achieved, and the sintering of the carrier is inhibited, and as a result, the high-temperature thermal stability and the catalyzing activity of the catalyst can be improved.

The invention discloses a high-activity propylene gas-phase epoxidation catalyst, TiO2-MoO3-Bi2SiO5/SiO2, for preparing propylene oxide and a preparation method thereof. The catalyst is used for a propylene gas-phase epoxidation reaction for preparing the propylene oxide, which takes molecular oxygen (O2) or nitric oxide (NO) as an oxidant; reaction conditions are moderate and no inhibitor is needed; the catalyst has high catalytic activity. The catalyst takes a SiO2 mesoporous material Bi2SiO5/SiO2 containing bismuth silicate (Bi2SiO5) as a carrier, MoO3 as an active component and TiO2 as an auxiliary agent. The catalyst comprises following components in percentage by mass: 64.6%-98.8% of the carrier Bi2SiO5/SiO2, 1.1%-22.8% of the MoO3 and 0.1%-12.6% of the TiO2. The mol ratio of Si to Bi in the carrier Bi2SiO5/SiO2 is 30-200. The catalyst is synthesized by using a hydrothermal method; molybdenum and titanium precursors in the active component MoO3 and the auxiliary agent titanic oxide are immersed into the carrier by an ultrasonic-assisted immersion method to prepare the catalyst.

The application discloses a preparation method of a surface-functionalized molybdenum carbide-carbon catalyst for a carbon dioxide hydrogenation reaction. The preparation method mainly comprises the following steps: firstly, using deionized water as a solvent, uniformly mixing sodium alginate with an ammonium molybdate solution, and then putting a mixed solution into a freeze drying oven for carrying out freeze drying; secondly, carrying out high-temperature roasting in an inert atmosphere to obtain porous graphite carbon-inlaid high-dispersibility molybdenum carbide; thirdly, mechanically lapping the prepared porous graphite carbon-inlaid high-dispersibility molybdenum carbide and urea, putting a lapped material into a muffle furnace, and carrying out annealing treatment to obtain the surface-functionalized molybdenum carbide-carbon catalyst. The catalyst prepared by the preparation method has the characteristics of large specific surface area, abundant pore structures and high dispersibility, and shows good catalytic activity and selectivity in the carbon dioxide hydrogenation reaction.

The invention discloses a catalyst CuOX-MoO3-Bi2SiO5/SiO2 for preparing propylene epoxide by propylene gas-phase epoxidation at the low temperature and a preparation method of the catalyst. The catalyst is applied to a reaction of preparing propylene epoxide from molecular oxygen (O2) or air as an oxidizing agent by the propylene gas-phase epoxidation, the reaction conditions are mild, inhibitorsare not required, and the catalyst keeps higher catalytic activity at the temperature of 300-380 DEG C. The catalyst adopts Bi2SiO5/SiO2 as a supporter, MoO3 as an active component and Cu as a modification aid, and is prepared from the components in percentage by mass as follows: 75.0%-95.0% of the supporter Bi2SiO5/SiO2, 4.2%-21.0% of MoO3 and 0.8%-4.0% of CuOX. A mole ratio of Si to Bi in the supporter Bi2SiO5/SiO2 is 50, the supporter Bi2SiO5/SiO2 is synthesized with a hydrothermal method, the active component MoO3 and the aid Cu impregnate Mo and Fe precursor to the supporter with an ultrasonic assisted co-impregnation method, and the catalyst is prepared accordingly.

The invention provides a method for producing superfine lead-free solder powder. The method is implemented in a reaction system composed of a high-temperature evaporator, a grain controller, a spraying tank, a collector and the like which are all communicated in sequence. Tin alloy is placed in the high-temperature evaporator to be heated and melted, the temperature is maintained for 1 to 3 hours to acquire even alloy liquid, the power of a plasma gun is then increased rapidly, the flow of nitrogen is adjusted, metal steam is conveyed to the grain controller so as to be gradually cooled, collide with one another and grow, and alloy drops are generated; the alloy drops enter the spraying tank through air flow and rapidly cooled through liquid nitrogen to form solder powder, the solder powder is conveyed to the collector along with the nitrogen, attached to the outer wall of a gas-solid separator in the collector and then collected to a collecting hopper at the bottom of the collector, and therefore the superfine solder powder is acquired, wherein the nitrogen is cyclically used. The superfine lead-free solder powder produced through the method is hemispherical, the average grain diameter ranges from 2 micrometers to 7 micrometers, the powder is distributed narrowly, the oxygen content is low, the purity is high, and alloy components are even.

The invention discloses a preparation method of a monatomic catalyst for preparing synthesis gas by methane dry reforming , the preparation process adopts a one-step synthesis method, the active component metal Ni in the obtained catalyst is uniformly dispersed on a carrier CeO2 in an isolated atom form, the catalytic stability can be effectively improved, and the preparation method has the advantage of simple steps. The invention also discloses the monatomic catalyst prepared by the method, monatomic dispersed Ni has high catalytic activity, Ni is limited by oxygen vacancy of CeO2, and sintering agglomeration of Ni at high temperature can be effectively prevented; and the doped second metal regulates and controls the oxygen vacancy concentration on the surface of CeO2, a large number of oxygen vacancies can effectively activate carbon dioxide, surface active oxygen is generated, and the influence of carbon deposition on the activity of the catalyst is inhibited. The invention also discloses an application of the monatomic catalyst in preparation of synthesis gas by methane dry reforming, the catalyst can be continuously used for 150 hours without obvious deactivation, and a good technical effect is achieved.

The invention relates to a preparation method of heavy metal adsorbent alpha-Al2O3 nanoparticles and belongs to the technical field of preparation of a nanometer sewage treating agent. A glycol aluminum precursor is prepared by an alcohol aluminum hydrolysis method and high-temperature calcination is conducted to obtain the alpha-Al2O3 nanoparticles. The preparation method comprises the followingsteps: A, dissolving aluminum powder into anhydrous glycol, controlling the molar ratio of the aluminum powder to the anhydrous glycol to be 1:(25-30), stirring, adding PEG6000, adding AlCl3, performing catalytic reaction, and stirring for 5 to 8 hours by controlling the temperature to be 50 to 70 DEG C to obtain glycol aluminum white precipitate; B, adding deionized water into the glycol aluminumwhite precipitate obtained in the step A, stirring by controlling the temperature and performing hydrolysis at 60 to 70 DEG C for 2 to 5 hours to obtain hydrated alumina gel; C, drying the hydrated alumina gel at 60 to 80 DEG C for 24 to 48 hours to obtain dry gel; and D, heating to 1100 to 1200 DEG C at the heating speed of 5 to 10 DEG C/min and calcining the dry gel for 2 to 3 hours to preparethe alpha-Al2O3 nanoparticles. The method is mild and stable in preparation process; and the prepared nanometer aluminum oxide has high purity and has high adsorptive property on various heavy metal ions.

The invention provides a preparation method of a carbon-based Fe/S/N co-doped oxygen reduction catalyst, and the method comprises the following steps: S1) copolymerizing phenyl ferriporphyrin and a cross-linking agent under the action of a catalyst to obtain a ferriporphyrin-based cross-linked microporous polymer; S2) mixing the ferriporphyrin-based cross-linked microporous polymer with thiophene for adsorption, and then performing polymerization under the action of an initiator to obtain a polythiophene coated ferriporphyrin cross-linked microporous polymer composite structure; S3) carrying out carbonization treatment on the composite structure obtained in the step S2) to obtain the carbon-based Fe/S/N co-doped oxygen reduction catalyst. The oxygen reduction catalyst shows efficient oxygen reduction electrochemical performance and stability, the half-wave potential of the oxygen reduction electrochemical reaction is (0.89 Vvs.RHE), and the oxygen reduction catalyst is superior to commercial platinum carbon; the maximum output power of the zinc-air battery is 106mW/cm<2>, which is superior to that of 20wt% commercial platinum carbon.

The invention belongs to the technical field of material synthesis and energy, and discloses a niobium tungstate material for a high-safety lithium ion battery as well as a preparation method and application of the niobium tungstate material. The molecular formula of the niobium tungstate material is Nb14W3O44, and the niobium tungstate material is prepared by uniformly mixing hydrated niobium oxalate, ammonium metatungstate and fuel in inorganic acid, carrying out self-propagating combustion reaction at the temperature of 1050-1250 DEG C in an air atmosphere and then carrying out calcinationreaction at the temperature, wherein the fuel is more than one of glycine, urea or glucose. The Nb14W3O44 material prepared by the method has excellent cycle performance, the capacity can be kept at 215.9 mAh g<-1> after 200 cycles at 0.5 C, and the capacity retention rate is as high as 98.1%. The electrochemical stability of the electrode material is obviously superior to that of a conventional Nb14W3O44 material synthesized by a solid-phase method and that of a commercial Li4Ti5O12 material.

The invention discloses a titanium silicalite molecular sieve and a modification method and application thereof, and belongs to the technical field of petrochemical engineering, and the modification method comprises the following steps: 1, pretreating the titanium silicalite molecular sieve, then mixing the pretreated titanium silicalite molecular sieve with silane and alkali metal hydroxide, and then carrying out ball milling treatment to obtain the titanium silicalite molecular sieve subjected to ball milling treatment; 2, uniformly dispersing the ball-milled titanium silicalite molecular sieve in an alkali solution, and then performing reacting at the temperature of 80-160 DEG C for 3-18 hours to obtain a primarily modified titanium silicalite molecular sieve; 3, in an inert gas atmosphere, carrying out heat preservation on the primarily modified titanium silicalite molecular sieve at the temperature of 500-800 DEG C for 4-36 hours to complete modification of the titanium silicalite molecular sieve. The modification method provided by the invention is simple to operate, and the prepared titanium silicalite molecular sieve has strong hydrophobicity, titanium species are not easy to lose, the stability is good, and the catalytic performance in propylene and hydrogen peroxide gas phase epoxidation reaction is good.

The invention discloses a preparation method of a denitration catalyst carrier TiO2. The preparation method comprises the following steps: firstly, preparing TiO2 used as a raw material into metatitanic acid by adopting a sulfuric acid method, and preparing the metatitanic acid into a suspension, and adjusting the pH of the suspension to be not more than 1; then, drop by drop adding a titanous sulfate solution, and performing filtration and washing; then anew preparing obtained filter residues into a suspension, and adjusting the pH value of the suspension to be 7.5+/-0.5 by ammonia water, and performing filtration and washing; then anew preparing obtained filer residues into a suspension again, and adjusting the pH value of the suspension to be 6.5 to 7.0 by acetic acid, and then performing filtration and washing; and carrying out low-temperature vacuum drying on the suspensions processed through the above-mentioned steps; finally, cooling and grinding to form powder. According to the invention, the existing preparation method of the denitration catalyst carrier TiO2 is improved, and the TiO2 preparation method which has simple process and does not require high-temperature heating is put forward, furthermore, the obtained product is high in quality and the high catalytic efficiency of a denitration catalyst is ensured.

The invention discloses a solid acid-bimetallic nanoparticle composite material as well as a preparation method and application thereof. The composite material disclosed by the invention is prepared from Pd-Co bimetallic alloy nanoparticles and a solid acid carrier ZrO2. The preparation method comprises the following steps: 1) dispersing zirconium salt, a polydentate carboxylic acid ligand and acid in an organic solvent, and carrying out solvothermal reaction to obtain a UiO-67-H material; 2) dissolving a palladium salt and a cobalt salt in a solvent, adding the UiO-67-H material, and carrying out a coupling coordination reaction to obtain a UiO-67-H immobilized PdCo salt material; and (3) the UiO-67-H immobilized PdCo salt material is subjected to a temperature programmed reduction pyrolysis reaction in a reducing atmosphere, and the solid acid-bimetallic nanoparticle composite material is obtained. The composite material can resist chlorine poisoning, has high catalytic activity and good stability, and is suitable for catalytic oxidation of chlorine-containing volatile organic pollutants.

A method for preparing waterborne epoxy coating used for an inner compartment of a ship is disclosed. The method includes fully mixing aluminum nitrate, zinc borate, polyvinyl alcohol 6000 and water;adding ammonia water dropwise under stirring until the pH value of the system is 8-8.4; stirring the mixture to obtain a white emulsion suspension; performing a hydrothermal reaction, centrifugation,washing, drying, calcination and cooling to obtain a material a; stirring bisphenol A type epoxy resin, bisphenol F type epoxy resin, epoxy alkyd resin, and trimethylhexamethylenediamine to obtain a material b; and stirring the material b, the material a, nanometer talc powder, vermiculite powder, diatomite, fly ash, zinc oxide, zinc phosphate, polyethylene glycol, a film forming auxiliary agent,an antibacterial agent, a dispersing agent, an anti-mold agent, a defoamer, a wetting agent and water to obtain the coating.

The invention discloses an anti-sintering treatment method of heavy metal particles, which comprises the following steps: by using heavy metal particles as damage elements, uniformly mixing with a molten anti-sintering agent, carrying out hot sieving granulation, and cooling to obtain the anti-sintering heavy metal particles. Tthe anti-sintering agent is any one or a mixture of more of stearic acid, calcium stearate and paraffin in any proportion. The anti-sintering heavy metal particles obtained through the anti-sintering treatment method have good formability and can be conveniently pressedinto a low-attached damage ammunition embedded layer, the heavy metal particles serving as damage elements are scattered in a single particle mode within a certain distance away from an explosion center under explosive loading of explosives. A damage range of the damage element is effectively controlled.