30results about How to "Control stoichiometric ratio" patented technology

The preparation method of egg yolk-eggshell structure nitrogen-doped carbon-coated ferric oxide@tin dioxide magnetic nano box belongs to the field of nanomaterial production technology. A layer of silicon dioxide is coated on the surface of ferric oxide cubic nano cubes, and then Under the action of potassium stannate trihydrate and urea, an egg yolk-eggshell structure ferric oxide@tin dioxide nanobox is formed, and finally dopamine is coated, carbon and nitrogen sources are introduced, and calcined in an inert atmosphere to form a conductive carbon layer, while converting ferric oxide to ferric oxide. The equipment adopted in the present invention is simple, the preparation cost is low, the operation process is simple and convenient, the materials required in the reaction process are low-toxic and harmless, and the stoichiometric ratio of multi-component materials can be effectively controlled to obtain uniform size, uniform distribution and good shape. Well-controlled, it can be used for industrial mass production of high-quality egg yolk-eggshell structured magnetic nanomaterials.

A method for preparing hollow carbon nanospheres with internal confinement growth of MOFs belongs to the field of nanomaterial production technology. Tetraethyl orthosilicate, ethanol, deionized water, ammonia water, resorcinol and formaldehyde are mixed and reacted to obtain SiO 2 @resorcinol‑formaldehyde resin microspheres, then calcined under argon to obtain SiO with core-shell structure 2 @C nanospheres are dispersed in sodium hydroxide aqueous solution and etched to obtain mesoporous hollow carbon nanospheres; finally, mesoporous hollow carbon nanospheres are dispersed in methanol, and metal nitrate and 2-methylimidazole are added for reaction. Hollow carbon nanospheres with internal confinement growth MOFs were obtained. The invention has simple equipment, low cost, simple operation process, low toxicity and harmless materials required in the reaction process, and can effectively control the stoichiometric ratio of multi-component materials, and the obtained products have uniform size, uniform distribution and good shape control .

The invention discloses a method of catalytic preparation of copper-indium-tellurium nanowires, and belongs to the field of production technologies of a new generation of film solar cell materials. The method comprises the following steps: respectively preparing methylbenzene solution of bismuth nanoparticles and precursor solution containing indium acetate, copper acetate and tellurium, heating trioctylphosphine under the protection of nitrogen, adding the methylbenzene solution of the bismuth nanoparticles, dropping the precursor solution containing the indium acetate, the copper acetate and the tellurium, after the reaction is completed, cooling and injecting methylbenzene, centrifuging, taking a solid phase and drying in vacuum after centrifugal washing through methylbenzene so as to obtain the copper-indium-tellurium nanowires. According to the method, the metal bismuth nanoparticles can be taken as a catalyst, the adopted instrument and equipment are cheap, the operation process is simple, a stoichiometric ratio of multi-component materials is effectively controlled to obtain the high-purity copper-indium-tellurium nanowires, and a large batch of high-quality nanowires can be produced. In addition, the length of the nanowires can be controlled through adjusting the concentration of the bismuth nanoparticles or the concentration of the precursor.

The invention provides a negative-thermal expansion and conductive ceramic powder body of Ce-doped zirconium tungstate and a preparation method thereof. The material comprises the component: Zr1-xCexW2O8 (wherein, the x is more than zero and less than or equal to 0.02); the preparation adopts the components ZrOCl2.8H2, 5(NH4)2O.12WO3.5H2O and (NH4)2Ce(NO3)6 as precursors, and uses a hydrothermal synthetic method. The negative-thermal expansion and conductive ceramic powder body of Ce-doped zirconium tungstate of the invention has not only negative thermal expansion, but also conductivity under the temperature of 350 to 700 DEG C. Compared with the traditional sintering method, the hydrothermal synthetic method avoids high-temperature sintering process, thus saving energy and simplifying synthetic technique.

The invention provides a crucible for growing a silicon carbide crystal through a physical vapor transport method. The crucible comprises a crucible body, wherein the crucible body comprises a bottom wall and a sidewall which encircle an inner chamber in which silicon carbide polycrystalline powder is stored; furthermore, an interlayer chamber for storing a silicon source is formed in the sidewall; the silicon source is used for supplying Si vapor pressure in the interlayer chamber, and the Si vapor pressure in the interlayer chamber is not less than that in the inner chamber. According to the crucible, the interlayer chamber is arranged in the sidewall of the crucible body, and the silicon source is positioned in the interlayer chamber and used for supplying proper Si vapor concentration, so that the spreading direction of Si vapor in a SiC monocrystal growing chamber can be controlled under the Si steam concentration gradient effect, and as a result, the stoichiometric ratio in the whole silicon carbide monocrystal growing process can be effectively controlled, and the defect that a carbonaceous inclusion is generated in the silicon carbide crystal can be avoided; moreover, raw materials can be prevented from serious carbonizing, and the high-quality silicon carbide growth can be promoted.

The invention relates to a gasoline selective hydrodesulfurization catalyst and preparation and application thereof. According to the total mass of the catalyst being 100%, the catalyst is prepared from 3-15 wt% of VIII group metal, 45-58 wt% of Mo and 35-40 wt% of S. A preparation method of the catalyst comprises the following steps that 1, a defect-rich molybdenum disulfide nanosheet precursor with a non-stoichiometric ratio is prepared; 2, one kind of VIII group metal is added into the molybdenum disulfide nanosheet precursor through an ultrasonic assisting dipping method, the molar ratio of the VIII group metal to Mo is (0.1-0.5):1, the specific surface area of the molybdenum disulfide nanosheet precursor ranges from 40 m<2> / g to 90 m<2> / g, the pore volume ranges from 0.1 ml / g to 0.25 ml / g, and the molar ratio of sulfur to molybdenum is (1.92-2.10):1. Defect-rich molybdenum disulfide is prepared by controlling the stoichiometric ratio of molybdenum disulfide, and meanwhile more active loci are exposed. Compared with an existing catalyst, the catalyst is applied to a gasoline selective hydrodesulfurization reaction, the hydrogenation saturation factor of olefin is low, and the hydrodesulfurization rate of a sulfur-containing compound is high.

The present invention relates to a method for rapidly preparing single-phase Bi2S3 thermoelectric compounds, which comprises the following steps: 1) preparing Bi powder and S powder as raw materials according to the stoichiometric ratio Bi:S=2:3.06, relative to the stoichiometric ratio of the compound Bi2S3 For example, the excess of raw sulfur powder is 2%, and then they are ground and mixed uniformly to obtain the reactant; 2) The reactant in step 1) is induced to self-propagating reaction or thermal explosion reaction, and after the reaction is completed, it is naturally cooled to obtain a single-phase Bi2S3 thermoelectric compound. The invention has the advantages of fast response speed, simple equipment, good repeatability, high efficiency and energy saving, and the like.