36results about How to "High crystal phase purity" patented technology

The invention relates to synthetic rare earth doped nitric oxide fluorescent powder and a preparation method thereof, which is characterized in that the general chemical formula of the rare earth doped nitric oxide fluorescent powder is A1-xByOzN2 / 3+4 / 3y-2 / 3z : xRe, wherein A is one or the combination of two or more of Ca ion, Sr ion and Ba ion and comes from the oxide, carbonate or nitrate whichcontains A element; B is one or the combination of Si ion and A1 ion, at least contains Si ion and comes from the nitride which contains B element; Re is one or the combination of two or more of Eu ion, Ce ion, Dy ion and Mn ion and comes from the oxide, nitrate or acetate which contains Re element; and the relations of X is more than or equal to 0 and less than 1.0, Y is more than or equal to 1.0 and less than or equal to 2.0 and Z is more than 0 and less than or equal to 2.0 are satisfied. The luminescent material is of stable physical and chemical properties, strong thermal decay resistance and high quantum efficiency, is suitable for excitation of wavelength at 300nm-600nm and is widely applicable in LED lighting and display devices. The fluorescent powder is synthesized through two-step synthesis by taking cheap compounds as the materials and the fluorescent powder synthesized through the method under normal pressure is of pure phase.

The invention belongs to the technical field of sodium ion batteries, and specifically discloses a fluorine-doped carbon-coated phosphate ferric sodium pyrophosphate @ mesoporous carbon composite material. The material comprises mesoporous carbon and fluorine-doped carbon-coated phosphate ferric sodium pyrophosphate dispersed in the mesoporous carbon in situ. The invention also discloses a preparation of the material and an application of the material as an active material for a sodium ion battery. The composite material of the invention has the characteristics of high specific capacity, highsafety and high rate as a positive electrode material of a sodium ion battery, and has rich system resources, low cost, a simple preparation method and a good application prospect.

The invention relates to a method for preparing a ferrum-fluorine-codoped nano-titanium dioxide visible light photocatalyst. The method comprises the following steps: (1) at the room temperature, adding nitric acid into the ethanol solution of tetrabutyl titanate dropwise, adding ferrum-fluorine-containing ethanol solution into the mixed solution with stirring, and stirring the mixed solution at the room temperature for 0.5 to 2 hours to perform a hydrolysis reaction to obtain light yellow titanium dioxide sol; (2) ageing the obtained titanium dioxide sol at the room temperature to obtain titanium dioxide gel, and drying the titanium dioxide gel to obtain dried titanium dioxide gel; and (3) grinding, screening and sintering the dried titanium dioxide gel to obtain the ferrum-fluorine-codoped nano-titanium dioxide visible light photocatalyst. The method has the characteristics of mild reaction conditions, easy control, simple equipment and rich raw material resources, simple synthetic process and high yield, and can be used for large-scale production; and the prepared ferrum-fluorine-codoped nano-titanium dioxide visible light photocatalyst has high performance.

A guiding agent for preparing 4A zeolite from the solution of sodium aluminate generated in the production of alumina features that the solution of sodium aluminate, water glass and sodium hydroxide are proportionally mixed while the Si / Al ratio and Na / Al ratio are controlled to be 5-20 and 10-25. Its advantages are high productivity and high quality of 4A zeolite.

The invention relates to the field of electrode materials, and discloses a solid electrolyte modified lithium titanate negative electrode material and a preparation method thereof. The microscopic appearance of the lithium titanate negative electrode material is as follows: the secondary particles are spherical, and the particle size is 5-20 μm. The secondary particles are composed of primary particles with a grain size of 20-200 nm; the lithium titanate particles in the lithium titanate negative electrode material are attached to the lithium ion solid electrolyte composed of fluoride oxide and fluoride, and the lithium ion solid electrolyte The mass fraction is 0.1-3%; its preparation method is: one or more fluorine-containing lithium battery electrolytes, titanium dioxide and lithium salts are subjected to two times of sand milling, two times of spray granulation and two times of solid-phase calcination have to. The tap density of the prepared lithium titanate negative electrode material reaches 1.3 g / cm 3 Above, the pH value is 8‑10, and has a good rate performance, the 5C discharge capacity reaches 135 mAh g ‑1 above.

The invention relates to the technical field of piezoelectric catalytic hydrogen production materials, and provides a tin, cerium-strontium titanate solid solution piezoelectric hydrogen production catalyst and a preparation method and application thereof. According to the material prepared by the present invention, its general chemical formula is Sn x Ce y Sr (1‑x‑y) TiO 3 (0<x≤0.15, 0<y≤0.15). In the present invention, Sr source, Ce source, Sn source and Ti source are mixed with water and ethylene glycol, and a co-precipitation method is used to prepare a precursor of a tin, cerium-strontium titanate solid solution piezoelectric hydrogen production catalyst, and finally calcined at high temperature A solid solution piezoelectric hydrogen production catalyst is formed. The results of the examples show that the introduction of Sn and Ce makes SrTiO 3 The piezoelectric hydrogen production performance has been greatly improved. And, when x=0.1, y=0.1, it has the best hydrogen production efficiency, reaching 411 μmol / g, much higher than SrTiO 3 of 53.45 μmol / g.

The invention provides a sodium iron phosphate pyrophosphate composite material coated with vanadium sodium fluorophosphate and its preparation method and application. By coating the sodium vanadium fluorophosphate on the surface of sodium iron phosphate pyrophosphate, the sodium iron phosphate pyrophosphate material can be effectively solved. Due to the problems of unstable phase transition, slow ion diffusion and poor cycle stability, its application in batteries can make the batteries have higher working voltage, good stability and excellent electrochemical performance.

This invention discloses a Li ion positive material and its preparation method solving the problem of reducing the circulation attenuation of the positive ionic material with the oxide general formula: xA2O.yM2Om.zN2On, the material is composed of 2-D hexagonal laminated crystal, compound oxide crystal of 3-D spinel structure or lithium vanadium oxide in the following processing steps: to electrolyse metal directly to form metal alkoxide in alcohol soluble absolute electrolyte containing organic additives then to mix with solution with assistant alkali salt or base to form positive sol precursor to dry to remove the solvent and form positive powder precursor under 120 to 550 deg.C. to process in solid phase reaction for 0.5-48h in 450-960 deg.c.

The application relates to a method for producing boehmite by using washing liquor from the production of washing red mud by alumina, which comprises the following steps: delivering washing liquor from the production of the washing red mud by alumina to a desilicication tank, and adding red mud and lime to perform desilicication; when a desilicication index is more than or equal to 400 as required, filtering the product of the desilicication, transferring filtrate to a diluting tank for cooling, cooling to 20 to 60 DEG C, performing carbonation gelatinizing by using 20 to 60 volume percent CO2 gas obtained by concentrating and enriching CO2 waste gas generated in the production of alumina as a precipitator; heating the gelatinized slurry to 70 to 100 DEG C, keeping the temperature for 1 to 6 hour and aging; and washing the aged slurry with washing equipment, filtering the aged slurry to obtain filtrate and filter cake, and drying the filter cake by using drying equipment to obtain powdery boehmite. The method has the advantages of low production raw material cost and rich raw material source, is favorable for alumina production liquid balance, improvement on finished alumina yield, reduction of Al2O3 content of red mud discharged to the outside and recovery of alumina CO2 waste gas and is in accordance with the national circulating economy and waste recycling principle. The product produced has high crystalline phase purity and high peptizing performance and can be used as a binder, a drier, a purifier, a catalyst, a catalyst carrier and the like.

The invention belongs to the field of electrode materials for sodium ion batteries, and specifically discloses a ferric sodium pyrophosphate phosphorus fluoride@C@RGO composite material. The compositematerial includes reduced graphene oxide and active particles compounded in situ on the surface of the reduced graphene oxide. The active particles are ferric sodium pyrophosphate phosphorus fluoride, and the chemical formula of the ferric sodium pyrophosphate phosphorus fluoride is Na4Fe3PO4P2O7F3. The invention also provides a preparation method and an application of the material. The materialhas the characteristics of high theoretical quantity, high voltage, stable cycling and low cost of raw materials, and has a good prospect of industrialization. It is discovered from the invention that, through the novel active ingredient and the innovative double-carbon in-situ composite morphology, the technical problems of phase transition, poor stability and poor electrical performance of the existing iron-based cathode material can be solved, and the voltage, capacity, rate and cycle stability of the material can be improved.

The present invention is artificial pure diopside crystal material and its preparation process. The artificial diopside crystal material is prepared with silica sand, tail pyrite, kaolin, albite, limestone and other mineral materials, and through the technological steps of compounding material, smelting, forming, annealing, coring, crystallization, etc. Chemically, the materials consist of SiO2 47-61 wt%, Al2O3 4-9 wt%, CaO 12-20 wt%, MgO 4-7 wt%, TiO2 2-15 wt%, NaO2+KO2 3-7 wt%, ZrO2 1-4 wt%, ZnO 0-4 wt%, P2O5 1-4 wt%, F 1-3 wt% and C 1-3 wt%. The artificial pure diopside crystal material consists of micron level crystal grains, and has high compactness, high mechanical performance, high wear resistance, high corrosion resistance, excellent impact performance, no radioactivity and other features.

The invention discloses a preparation method of nano strontium barium titanate powder, which is used to solve the technical problems of large particle size, uneven distribution and impure crystal phase of the prepared strontium barium titanate powder prepared by the preparation method in the prior art. Its technical scheme puts barium acetate, strontium acetate, tetra-n-butyl titanate, sodium oleate, oleic acid, n-butanol and sodium hydroxide into a hydrothermal kettle to heat and react, washes out the precipitate with ethanol, and then washes out the precipitate with cyclohexane Then add ethanol to the mixed solution to produce nanocrystalline BST precipitate at room temperature, centrifuge the nanocrystalline BST precipitate, wash the residual oleic acid with ethanol, and dry it at room temperature. The present invention adopts the liquid-solid solution method to prepare barium strontium titanate powder, the particle size of the barium strontium titanate powder prepared is reduced from more than 50nm in the prior art to 10-25nm, and the particle size distribution is uniform, and the crystal phase purity is also obtained. improve.

The invention provides a preparation method of single-substrate fluorescent powder for white-light LEDs (light-emitting diodes), which comprises the following steps: after completely dissolving Tb4O7 in a concentrated nitric acid solution, regulating the pH value to 4-7 with ammonia water, sequentially adding anhydrous CaCl2, Ca(NO3)2.4H2O and anhydrous ethanol, uniformly stirring, adding a slow release agent citric acid solution, continuously stirring until the slow release agent is uniformly dispersed in the solution, adding ethyl silicate, and stirring to form a uniform and transparent solution; and regulating the pH value of the uniform and transparent solution to 6-8 with ammonia water to form a gel, drying the gel, grinding to form powder, putting the dry gel powder in a resistance furnace, and sintering in a weak reducing atmosphere. The preparation method provided by the invention implements activation of the Ca2SiO3Cl2 substrate to emit white light by using the single Tb<3+>.

The invention provides a method for repairing carbon-composite vanadium phosphate, comprising the following steps: step 1, detecting the vanadium dissolution rate and element content of carbon-composite vanadium phosphate to be repaired, and judging whether the failure degree of carbon-composite vanadium phosphate and the ratio of element content are out of balance; step 2. Mix the coated reducing agent with the carbon composite vanadium phosphate to be repaired, the amount of the coated reducing agent is calculated according to the vanadium dissolution rate of the carbon composite vanadium phosphate to be repaired; step 3, the mixed material is treated at high temperature to obtain Repaired carbon composite vanadium phosphate. This repair method can effectively repair and regenerate materials that have been oxidized and deteriorated due to long-term placement in the air. The dissolution rate recovered to a level below 2000mg / kg.

The present invention provides a preparation method of lithium vanadium fluorophosphate and application thereof. The method of the present invention is summarized into two steps. The first step is to prepare carbon-coated vanadium phosphate (VPO) by a sol-gel method. 4 @C) or carbon-coated vanadium trioxide (V 2 O 3 @C); the second step is low-temperature solvothermal preparation of carbon composite LiVPO 4 F. First step to prepare carbon-coated VPO using sol-gel method 4 @C or V 2 O 3 @C, carbon composite precursors with small particle size and uniform distribution can be obtained. The present invention adopts low-temperature hydrothermal synthesis of LiVPO through the second step 4 F, on the one hand, effectively avoids the volatilization of F, and prepares high-purity LVPF materials at low temperature; Obtained LiVPO 4 F@C powders have nanoscale morphologies, high crystal phase purity, and excellent performance close to the theoretical specific capacity at low magnifications.