31results about How to "Reduce phase temperature" patented technology

The invention discloses a preparation method of mesoporous hollow sphere-shaped tungsten carbide. The preparation method comprises the following steps: (1) preparing 30%-70% ammonium metatungstate solution at room temperature; (2) fixing a glass container with absolute ethanol in an ultrasonic apparatus, adding the ammonium metatungstate solution obtained in the step (1) at the speed of 1-5 mu l / drop at an interval of 2-8 seconds per drop in the absolute ethanol in the presence of ultrasonic, immediately pelleting and then generating precipitate, dispersing the precipitate by continuous ultrasonic action, and then obtaining ammonium metatungstate particles by filtration and vacuum drying; and (3) carbonizing the obtained metatungstate particles at the atmosphere of CO / H2, and then obtaining the mesoporous hollow sphere-shaped tungsten carbide. The preparation method is simple to operate, the used solvent is clean and environment-friendly, and the prepared metatungstate particles consist of nano tungsten carbide particles.

The invention discloses a preparation method of an NASICON-type lithium ion solid electrolyte. The method comprises the following steps: dissolving lithium nitrate and aluminum nitrate in a citric acid solution, and stirring to form a transparent and uniform nitrate mixed solution; dissolving tetrabutyl titanate in anhydrous ethanol, and stirring to form an alcoholic solution of tetrabutyl titanate; slowly adding the alcoholic solution of tetrabutyl titanate to the nitrate mixed solution, and stirring to a transparent mixed solution; dissolving ammonium biphosphate in water to obtain a saturated aqueous solution of ammonium biphosphate, adding the saturated aqueous solution of ammonium biphosphate to the transparent mixed solution in a dropwise manner, and stirring to obtain an emulsion; adjusting the pH value of the emulsion, and drying the emulsion to obtain an xerogel; carrying out heat treatment of the xerogel, and grinding the obtained xerogel to form fine powder which is precursor powder; and compacting the precursor powder to form a green body, and sintering to obtain NASICON-type lithium ion solid electrolyte slices. The method has the advantages of low energy consumption, simplicity, easy implementation, and convenience for large-scale industrialized production, and the obtained solid electrolyte has a high conductivity.

The invention discloses a synthesis method for a La<x>Sr<1-x>Ti<1-y>Mn<y>O<3> (x=0.1-0.6, and y=0.1-0.6) material for a solid oxide fuel cell. N,N-dimethylformamide (DMF) is adopted as a solvent, tetrabutyl titanate is adopted as a titanium source and manganese acetate is taken as a manganese source, so that the process is simple, the prepared powder is uniform in particle size distribution and the particle sizes are smaller than 50nm. The powder prepared through the method is suitable for laboratory synthesis and industrial production of a positive electrode material for the solid oxide fuelcell and a connector material.

The invention belongs to the technical field of information functional materials and in particular relates to BiFeO3-Bi0.5Na0.5TiO3 base multiferroic solid solution ceramic and a preparation method thereof. The preparation method comprises the following steps of: dissolving bismuth nitrate and ferric nitrate in a citric acid solution to form a transparent BiFeO3 solution; dissolving butyl titanate, bismuth nitrate and sodium nitrate into the citric acid solution to form a transparent Bi0.5Na0.5TiO3 solution; mixing the BiFeO3 solution and the Bi0.5Na0.5TiO3 solution by a certain molar ratio and then regulating the pH value to 7-7.5 with ammonia water; aging, dewatering and drying the mixed solution to form black xerogel; grinding the xerogel and carrying out heat treatment to remove organic matters to obtain precursor powder; and grinding, tabletting and sintering the precursor powder to obtain the BiFeO3-Bi0.5Na0.5TiO3 base multiferric solid solution ceramic. The BiFeO3-Bi0.5Na0.5TiO3 base multiferric solid solution ceramic has the characteristics of single phase structure, low leakage current, ferroelectric / ferromagnetic coexistence at room temperature, and the like and has wide application prospect in the aspects of manufacturing emerging spin valve devices, magnetoelectric storages, magnetoelectric sensors and microwave resonance devices.

The invention discloses a method for preparing mesoporous needle-shaped tungsten carbide. The preparation method comprises the following steps of: controlling the ambient temperature to be 10-30 DEG C; adding deionized water into ammonium meta-tungstate and ammonium carbonate which has a mass ratio of 1:0.75-2, for preparing a precursor culture solution in which the total mass fraction of the ammonium meta-tungstate and the ammonium carbonate is 2.5-50 wt%; stirring the precursor culture solution for 1-15 minutes, then placing the precursor culture solution in an open system for 2-24 hours, and obtaining self-growing ammonium meta-tungstate needle-shaped crystal after centrifuging and drying; and carrying out one-step reduction and carbonization of the self-growing ammonium meta-tungstateneedle-shaped crystal in a hydrogen-rich atmosphere, and thus obtaining the mesoporous needle-shaped tungsten carbide. The mesoporous needle-shaped tungsten carbide prepared by the preparation methodis formed by the piling of nano-tungsten carbide grains, has controllable crystal length, well-developed aperatures, is simply prepared and operated and can be well used in the crystallization field.

The invention discloses a method for preparing submicron NaNbO3 ceramic powder at low temperature. The method comprises the following steps of: preparing a stable niobium oxalate solution; dissolving anhydrous sodium carbonate in deionized water; preparing a NaNbO3 precursor solution; and obtaining the NaNbO3 pure phase. The method disclosed by the invention is simple in process, low in requirements for equipment, low in synthesis temperature, short in thermal insulation time, low in energy consumption, and cheap in required material, the prepared powder has the characteristics of good crystalline grain development degree, fine granularity, and very light aggregation, and phase formation temperature is especially low.

The invention discloses a biosensor for detecting biogenic amine and a preparation method thereof, belonging to the technical field of sensor detection. The biosensor comprises an electrode with the surface provided with a composite film, the composite film consists of an electrochemical indicator, biogenic amine enzyme, and metallic oxide nanoparticles doped with conductive metals; the metallic oxide has semiconductor property; the mole percent of the conductive metals and the metallic oxide is 0.5-10mol%. According to the biosensor, the surface of the electrode is coated with the metallic oxide nanoparticles doped with conductive metals, the electrochemical indicator and biogenic amine enzyme; the nanoparticles are introduced to the construction of the biological sensitive interface by utilizing the surface effect, quantum size effect and dielectric confinement effect and the like of the nanoparticles; the conductive metals are doped in the metallic oxide nanoparticles; the electron transfer efficiency of the composite film is improved, redox electrochemical signals are enhanced, the sensitivity of the sensor is improved and the detection limit is lowered.

The invention relates to a preparation method of a flaky aluminate green phosphor. The preparation method comprises the following steps: 1, respectively weighing corresponding raw materials according to the amount of an object product to be prepared and the stoichiometric ratio of all metal elements in Ce1-xTbxMgAl11O19, and preparing a mixed nitrate solution of metals contained in the object product; 2, adding an organic fuel to the mixed nitrate solution obtained in step 1, and heating to dissolve; 3, adding ammonium fluoride to the mixed solution obtained in step 2, heating to dissolve, and continuously concentrating the mixed solution until that the mixed solution is in an approximately sticky state; 4, initiating the sticky solution obtained in step 3 to be subjected to self-propagating combustion; 5, post-treating self-propagating combusted products obtained in step 4; and 6, washing, drying, grinding, and sieving the product obtained in step 5 to obtain the object product. The preparation method of the invention, which has the advantages of phase forming temperature reduction, calcining time shortening, excellent luminescent performance, controllable particle size, uniform size, regular morphology, simple enforcement, low cost, rapidness, and energy saving, has a good industrialization application prospect.

A preparation method for a strontium titanate lanthanum based powder material belongs to the field of fuel cells. The method adopts a citric acid-nitrate spontaneous combustion method, using citric acid as a complexing agent and a reducing agent, using nitric acid as an oxidizing agent, introducing a sintering acid ammonium nitrate in-situ, dissolving with metal nitrate in deionized water, adding a tetrabutyl titanate citric acid solution to form an even transparent solution, heating in water bath, removing surplus water, forming even sol, and heating the sol in a muffle furnace till spontaneous combustion happens to form fluffy precursor powder. Then Grinding and calcining in an electric furnace to obtain single strontium lanthanum based anode powder. The preparation method has the advantages of being simple in synthesis process, low in cost, fine and even in powder particles and low in material phase forming temperature. The method is also applicable to synthesis preparation of strontium titanate based nanometer powder and can be used for laboratory synthesis and industrial production of a solid oxide fuel cell anode powder material.

The invention discloses a method for preparing a double mesoporous high (100) crystal plane tungsten carbide material. The method comprises the following steps of: (1) preparing a mixed aqueous solution of ammonium meta-tungstate and copper sulfate, adding a 5 to 50 mass percent ammonium carbonate aqueous solution dropwise at the speed of 50 to 200mu L / min during ultrasonic oscillation to deposit solid particles, and filtering after a dropwise adding process to obtain precursor particles; (2) drying the precursor particles in vacuum at the temperature of between 60 and 100 DEG C, putting the precursor particles into a tube furnace and carbonizing to obtain a mesoporous tungsten carbide composite material; and (3) performing acid treatment on the mesoporous tungsten carbide composite material, and thus obtaining the double mesoporous tungsten carbide material. Double mesoporous tungsten carbide (WC) which is prepared by the method is formed by piling up nano WC particles, and the growth of a WC (100) crystal plane is promoted, so that the sorption / desorption capacity of the WC to hydrogen (H2) and the electro-catalysis property of the WC are improved.

The invention discloses a preparation method of a nanosilver-doped yttrium barium copper oxide film, which comprises the following steps: 1. preparing a nanosilver sol by electrochemical reaction, adding the nanosilver sol into a yttrium barium copper oxide precursor liquid to prepare a precursor sol; 2. evenly applying the precursor sol on a CeO2 / YSZ / Y2O3 / NiW substrate to obtain a wet film; 3. carrying out low-temperature pyrolysis to obtain a precursor film; 4. crystallizing to obtain the nanosilver-doped yttrium barium copper oxide film. The electrochemical reaction for preparing nanosilver particles does not need dispersant, reducer or other complex compounds, and can easily obtain the high-purity impurity-free nanosilver sol; the nanosilver particles in the prepared precursor sol aredistributed uniformly, do not aggregate, and have high stability, and the dimension of the nanosilver particles is smaller than 20 nm; the nanosilver-doped yttrium barium copper oxide film obtained by applying the precursor sol has the advantages of low phase formation temperature and uniform nucleation, and has a superconductive layer which is 400-600nm thick and has excellent superconductivity.

The invention provides a preparation method of graphene-coated nano dysprosium oxide. The method comprises the following steps that dysprosium oxide nanoparticles are prepared through a pyrolysis method; 2, dysprosium oxide nanometer columns are prepared through a hydrothermal method; 3, a graphene oxide solution is prepared; 4, the dysprosium oxide nanoparticles and the dysprosium oxide nanometer columns are added into the graphene oxide solution, stirring and filtering are conducted in sequence, filter residues are obtained, and the filter residues are subjected to heat treatment to obtain graphene-coated nano dysprosium oxide. In addition, the invention provides application of graphene-coated nano dysprosium oxide prepared through the method in the process of preparing two-element-doped magnesium diboride superconducting bulk materials. According to the preparation method, the technological method is simple, graphene with high surface area is adopted as a coating, the dysprosium oxide nanoparticles and the dysprosium oxide nanometer columns can be uniformly dispersed on the graphene without generating agglomeration, and the critical current density Jc performance of the two-element-doped magnesium diboride superconducting bulk materials in a low field and a high field can be improved conveniently.