178 results about "Tin dioxide" patented technology

The invention relates to the technical field of synthesis and preparation of nano materials, in particular to a method for preparing tin dioxide powder, which comprises the following steps: S1, preparing a 0.1-5 mol / L tin salt solution, adding a compound additive into the tin salt solution, and carrying out ball milling treatment after ultrasonic dispersion to obtain a pretreated tin salt solution; s2, freezing and freezing the pretreated tin salt solution in an ultralow-temperature environment to obtain a frozen sample; s3, transferring the frozen sample into a vacuum freeze dryer for dehydration treatment to obtain solid powder; and S4, carrying out high-temperature calcination on the solid powder to obtain tin dioxide powder. Zero sewage discharge is achieved in the preparation process, the problem of sewage discharge and treatment of traditional liquid-phase powder preparation is solved, meanwhile, the phenomenon of sintering agglomeration accompanied by traditional solid-phase calcination can be avoided, high-quality superfine tin dioxide powder preparation is achieved, the method is simple and safe in process, and industrial large-scale production and preparation are easy to achieve.

The invention relates to the technical field of glass, in particular to an alkali-free aluminoborosilicate glass composite clarifying agent and a clarifying method thereof. The alkali-free aluminoborosilicate glass composite clarifying agent is prepared from the following raw materials in percentage by mass on the basis of the total mass of alkali-free aluminoborosilicate glass: 0.4 to 5.5 percent of halogen alkaline earth metal salt, 0.03 to 0.4 percent of lanthanum oxide, 0.01 to 0.4 percent of tin dioxide and 0.01 to 0.3 percent of cerium dioxide. The alkali-free aluminoborosilicate glass composite clarifying agent is applied to alkali-free aluminoborosilicate glass, and the problems that the alkali-free aluminoborosilicate glass is poor in clarifying effect and has many bubble defects are solved; the corrosion of high-temperature molten glass to refractory materials at parts such as a tank furnace and the like is reduced, so that the number of stone defects of the refractory materials in the glass is reduced, and the service life of the refractory materials of the furnace is prolonged.

The invention discloses a stannic oxide-based ammonia gas sensor as well as a preparation method and application thereof, relates to the technical field of gas sensors, and solves the problems of high detection lower limit, poor gas selectivity and low sensitivity of a traditional semiconductor ammonia gas sensor. A sensitive material based on oxygen vacancy regulation and control SnO2 / ZIF-67 is prepared on the surface of an interdigital gold electrode by adopting a chemical vapor deposition method, a planar electrode, an aluminum oxide ceramic substrate, a heater and a Pt wire are welded and packaged according to a general indirectly-heated gas sensitive element, and the SnO2 / ZIF-67 semiconductor ammonia gas sensor is prepared. The lower detection limit of the SnO2 / ZIF-67 semiconductor ammonia gas sensor is 1 ppm; meanwhile, the NH3 selectivity and sensitivity of the sensor are improved through the synergistic effect of SnO2 and ZIF-67, and the sensor can be used for detecting ammonia gas leakage and can be applied to judging the safety of ammonia gas in chemical production operation, environmental gas detection and other applications.

The invention relates to a preparation method of an oxygen vacancy-rich bismuth molybdate / bismuth vanadate composite photo-anode and a product and application thereof, and belongs to the technical field of photoelectrocatalysis. The invention discloses a preparation method of an oxygen vacancy-rich bismuth molybdate / bismuth vanadate (Bi2Mo2O9 / BiVO4) composite photo-anode, which mainly comprises the following steps: immersing a fluorine ion-doped tin dioxide (FTO) conductive glass substrate into a Bi < 3 + > ion solution and an I <-> ion solution to form a bismuth oxyiodide (BiOI) film, dropwise adding a dimethyl sulfoxide solution of vanadyl acetylacetonate (VO (acac) 2), and putting into a muffle furnace to prepare the BiVO4 photo-anode. And then vertically immersing into a Bi < 3 + > ion solution and a Mo < 6 + > ion solution, and carrying out annealing treatment in an argon atmosphere to prepare the Bi2Mo2O9 / BiVO4 composite photoanode rich in oxygen vacancies. The Bi2Mo2O9 / BiVO4 material rich in oxygen vacancies is a metal oxide composite photo-anode, the photoelectrocatalysis efficiency can be improved, and hydrogen peroxide (H2O2) can be continuously generated in natural seawater through photoelectrocatalytic oxidation of water for a long time.

The invention discloses a method for modifying a buried interface of a perovskite solar cell, and the method specifically comprises the following steps: 1) dissolving potassium stannate powder in deionized water to prepare an aqueous solution with the concentration of 1-5mg / mL, and filtering the aqueous solution; 2) coating the aqueous solution on a tin dioxide thin film by adopting a spin-coating method; and 3) annealing the tin dioxide film coated with potassium stannate to form a potassium stannate interface modification layer. Compared with the prior art, the method has the advantages that PS is used as a SnO2 / perovskite interface modification layer, stannate ions can passivate oxygen vacancies on the surface of SnO2, surface defects of SnO2 are reduced, and accumulation and compounding of electrons between interfaces are inhibited by balancing the energy level between SnO2 and perovskite. K < + > promotes high-quality perovskite crystallization and reduces grain boundary defects; a-site cation vacancy is filled, the crystal structure stability of perovskite is enhanced, a more stable crystal phase is formed, the quality of the perovskite film is improved, and the device performance is further improved.

The invention discloses a preparation method of a three-dimensional split-phase fancy glaze for coal gangue ceramic body decoration, the three-dimensional split-phase fancy glaze comprises a ground glaze and a cover glaze, the cover glaze comprises the following raw materials by weight: 15-20% of quartz, 10-15% of calcite, 5-10% of kaolin, 5-10% of zinc oxide, 10-15% of calcium phosphate, 25-30% of potassium feldspar, 2-5% of calcium borate, 5-10% of tin dioxide, 3-5% of spodumene, and 2-5% of a coloring oxide; the ground glaze is prepared from the following raw materials in percentage by weight: 15-20% of quartz, 10-15% of wollastonite, 5-10% of kaolin, 10-15% of zinc oxide, 15-20% of calcium phosphate, 15-20% of spodumene, 5-10% of titanium dioxide, 5-10% of calcium borate, 2-5% of coal gangue and 2-5% of coloring oxide, and the product is obtained through raw material preparation, glazing and sintering. The prepared three-dimensional split-phase fancy glaze is simple in process, high in adaptability, unique in effect and wide in market prospect.

The invention provides a preparation method and application of a gold-loaded tin dioxide catalyst, the gold-loaded tin dioxide catalyst can be used for catalyzing methane oxidation to prepare methanol, the preparation method comprises the following steps: dissolving a tin source and a gold source in water to obtain a mixed solution; drying the mixed solution, and grinding into powder; and carrying out high-temperature calcination treatment on the powder under the protection of a vacuum inert atmosphere to obtain the gold-loaded tin dioxide catalyst, which is a gold / tin dioxide catalyst and comprises a tin dioxide carrier and gold nanoparticles loaded on the carrier. In the prepared gold / tin dioxide catalyst, a gold-tin alloy layer is formed on the surfaces of gold particles loaded on tin dioxide, and under the action of water, carbon monoxide assists oxygen activation to generate hydroxyl radicals, so that oxygen-containing compounds can be prepared by efficiently oxidizing methane, and the methanol production rate and selectivity in methane oxidation reaction are improved.

The invention discloses a nitric acid type system tin stripping liquid centralized recovery treatment process which comprises the following steps: firstly, adding a cationic coagulant into a nitric acid type tin stripping waste liquid, filtering through a 5-micron filter membrane, discharging into a reaction kettle, and adding a H2O2 solution with the concentration of 5-10%; the pH is adjusted to 2.0-2.5, and copper is removed under the condition of 40-50 DEG C; when the pH value is increased from 2.5 to 3.0-3.5, iron is removed; adjusting the pH value to 13.0-13.5, heating to remove aluminum, and separating to obtain a filtrate containing Na2SnO3; adjusting the pH value of the filtrate to 6.0-6.5, heating to 70-75 DEG C for reaction, and then carrying out gradient cooling to room temperature to generate Sn (OH) 4 precipitate; and centrifugally separating the mixed solution to obtain a tin-containing solid and a tin stripping regenerated solution, and firing the tin-containing solid to obtain a tin dioxide solid. Compared with a traditional process, copper is removed firstly, then iron is removed, aluminum is finally removed, and directional removal is achieved through the difference of precipitation conditions.

The invention belongs to the technical field of metal resource recovery and reutilization, and particularly relates to a selective recovery method for valuable metal in a retired crystalline silicon cell photovoltaic welding strip. The method comprises the following steps: disassembling a photovoltaic solder strip from a retired crystalline silicon cell, and removing impurities from the photovoltaic solder strip to obtain a clean solder strip; adding the clean welding strip into an acetic acid solution, heating and stirring to fully react, and filtering to respectively obtain filter residues, copper strips and lead-containing filtrate; adding a precipitant into the lead-containing filtrate to carry out precipitation reaction, and after the reaction is finished, carrying out solid-liquid separation, washing and drying to obtain a lead sulfate product; washing and drying filter residues to obtain a tin dioxide crude product; and washing the copper bar with absolute ethyl alcohol, and drying to obtain the metal copper bar with the purity not lower than 99.0%. The method has the advantages of high metal separation efficiency, high recovery rate, low energy consumption, low acid and alkali consumption, difficulty in causing secondary environmental pollution and the like, and provides a feasible solution for selective separation and recovery of valuable metals of retired photovoltaic modules.

The invention relates to a microcrystalline plate produced on the basis of hazardous waste incineration ash, which comprises fly ash, bottom slag, silica sand, anhydrous sodium carbonate, sodium nitrate, anhydrous potassium carbonate, sodium fluosilicate, stannic oxide, nickel oxide, cobalt oxide, anhydrous borax, cerium dioxide, manganese dioxide and lanthanum oxide, an all-electric melting glass kiln is adopted for vitrification, a crystallization process adopts a one-step method for crystallization, and the crystallization process adopts a one-step method for crystallization. The fly ash and the bottom slag are obtained by incinerating medical wastes belonging to hazardous wastes in a rotary kiln, and are belonging to hazardous wastes; the method not only helps to solve the problem of disposal of the medical waste incineration ash, but also can promote development of the green building material industry, and conforms to the strategic target of sustainable development.

The invention discloses a high-stability MEMS hydrogen sensor and a preparation method thereof. The high-stability MEMS hydrogen sensor is a semiconductor resistance type hydrogen sensor based on a metal oxide gas sensitive coating and sequentially comprises a silicon nitride supporting layer, a Pt / Ti heating electrode, a sensing electrode, a silicon nitride isolating layer and a metal oxide gas sensitive film from bottom to top. The metal oxides are high-purity antimony doped tin dioxide, tetraamino palladium nitrate and tetraammineplatinum nitrate. The preparation method comprises the following steps: mixing high-purity antimony-doped tin dioxide powder, tetraamino palladium nitrate powder and tetraammineplatinum nitrate powder, preparing gas-sensitive slurry from a mixed solution of terpilenol, diethylene glycol butyl ether acetate, ethyl cellulose, dibutyl phthalate and dioctyl phthalate, dispensing the gas-sensitive slurry on a central interdigital electrode area of an MEMS chip, and performing vacuum drying to obtain the gas-sensitive MEMS chip. And performing vacuum standing and slow heating to obtain the sensor. The sensor is low in detection lower limit and stable in resolution ratio after high-humidity aging.

The invention discloses a preparation method of a high-efficiency gas sensor for confinement isolated platinum atoms based on porous SnO2 nanorods, isolated Pt atoms are precisely deposited in SnO2 pore channels through an ALD technology, and the working temperature (190 DEG C) of the sensor is remarkably reduced by utilizing a confinement effect and a monatomic catalysis synergistic effect, so that the gas sensor has high sensitivity and high sensitivity. The sensitivity (Ra / Rg = 6.33 at5ppm) to acetone, the response speed (9 seconds) and the stability (the attenuation rate is 2.8% in 28 days) are improved. The sensor has wide application prospects in the fields of medical diagnosis, environmental monitoring and the like.

The invention provides a tin dioxide transistor biosensor, a preparation method thereof and a cortisol concentration detection method. According to the tin dioxide transistor biosensor, the tin dioxide thin film layer is used as a channel material of the transistor to establish the activation layer; a channel is functionalized by using the PMMAA material layer to form a carboxylic acid functionalized activated interface, and meanwhile, the biocompatibility of the interface can be increased, the tin dioxide film is protected from being invaded and disturbed by the external environment, and the specificity and sensitivity of the tin dioxide transistor are improved; and after the target substance is tested on the tin dioxide thin film transistor, the recycled tin dioxide thin film transistor can be obtained again by washing off the PMMAA material layer on the tin dioxide thin film layer. According to the cortisol concentration detection method disclosed by the invention, along with the change of the concentration of the target substance cortisol, the cortisol concentration detection method has good linearity at 1-106pg / mL, and the detection limit is as low as fg / mL level.

The invention relates to the technical field of an electrode composed of an active material or comprising the active material, in particular to a preparation method and application of an MXene / Sn composite material. The invention provides a preparation method of an MXene / Sn composite material, which comprises the following steps of: S101, preparing porous tin: in an inert gas or vacuum environment, atomizing molten tin alloy gas to obtain solid powder particles, and etching by using acid or alkali to obtain the porous tin; s102, porous tin surface treatment: carrying out surface oxidation treatment on the porous tin obtained in the step S101 to form tin dioxide sites or thin layers on the surface of the porous tin; s201, MXene is prepared and obtained; s202, surface modification of MXene: MXene obtained in S201 is treated with hydrogen peroxide, and then carboxyl or amino is introduced; and S3, porous tin and MXene are compounded, the dispersion liquid of the porous tin obtained through treatment in the step 102 is mixed with the dispersion liquid of the MXene subjected to surface modification in the step 202, and compounding is completed through electrostatic attraction. The self-agglomeration phenomenon in the charging and discharging process can be inhibited, and the high energy density is achieved.

The invention discloses a series of high-stability negative temperature coefficient heat-sensitive materials based on seven-principal-element high-entropy rare earth stannate and application, and aims to solve the problem that existing stannate heat-sensitive materials with pyrochlore structures cannot meet long-term application in high-temperature environments. The series of heat-sensitive materials are prepared by mixing lanthanum trioxide, neodymium oxide, samarium oxide, europium oxide, gadolinium oxide, dysprosium oxide and tin dioxide with erbium oxide or ytterbium oxide respectively, and the preparation process comprises the steps of wet three-dimensional vibration ball milling, powder calcination, cold isostatic pressing, high-temperature sintering and the like. And finally obtaining the negative temperature coefficient heat-sensitive material with the pyrochlore structure. The electrical property parameters of the series of materials are as follows: B is equal to 13914-14067 + / -1.89% K, and rho 1500 DEG C is equal to 180.26-204.09 + / -1.38% omega.cm. The negative temperature coefficient heat-sensitive material has the negative temperature coefficient characteristic in the wide temperature range of 400-1500 DEG C and shows excellent high-temperature aging stability under the high-temperature condition of 1500 DEG C, and the resistance drift rate of the negative temperature coefficient heat-sensitive material is only 0.7% after an aging test for 500 hours.

The invention relates to the technical field of lithium ion battery electrode materials, and discloses a carbon-coated tin dioxide / MBene nano composite negative electrode material and a preparation method and application thereof, and the preparation method comprises the following steps: preparing MBene through a hydrothermal etching method; the preparation method comprises the following steps: performing in-situ growth of SnO nanoparticles on MBene through a hydrothermal method to obtain a tin dioxide / MBene composite material; and adding a carbon source and carrying out carbonization treatment to form a carbon coating layer on the surface of the tin dioxide / MBene composite material. The prepared composite material effectively solves the problems of volume expansion, poor conductivity and unstable interface of SnO. The composite material disclosed by the invention is used as a lithium ion battery negative electrode active material, has high specific capacity, ultra-long cycle life and excellent rate capability, is simple and controllable in preparation process, and has the feasibility of large-scale production.

The invention relates to the technical field of electrochemical water treatment, in particular to a preparation method of a self-supporting antimony-doped tin dioxide nanoflower electrode, which comprises the following steps: dissolving trisodium citrate dehydrate and antimony trichloride in absolute ethyl alcohol; then adding water and stannous chloride dehydrate to form a precursor solution; heating the precursor solution, and naturally cooling; after cooling, carrying out solid-liquid separation on the bottom mud, and then cleaning and drying to obtain antimony-doped tin dioxide powder; taking antimony-doped tin dioxide powder, a pore-forming agent and a binder, grinding the materials until the materials are uniformly mixed, and transferring the materials into a tabletting mold for pressure casting to obtain a blank; and calcining the green body to obtain the product. Nano-flower-shaped antimony-doped tin dioxide powder is prepared, in the die casting and sintering process, due to the fact that nano-flower petals of the nano-flower-shaped antimony-doped tin dioxide powder are mutually staggered, a connection mode similar to a mortise and tenon joint mode is formed, and compared with nanospheres, the binding force between the powder is enhanced; and the mechanical strength, the electrochemical active area and the catalytic activity of the electrode are improved.

The application relates to a preparation method of a tin dioxide negative material, and belongs to the technical field of lithium battery negative material synthesis. The application aims at solving the problems of the existing SnO2 negative material, such as large volume effect in the charging and discharging process, easy falling off on the current collector, complex preparation process of the SnO2 negative material and high cost. The preparation method comprises the following steps: S1, preparing a micro-arc oxidation electrolyte; S2, placing a titanium foil and the micro-arc oxidation electrolyte in a micro-arc oxidation electrolytic tank, taking the titanium foil as a positive electrode and a stainless steel plate as a negative electrode; and S3, micro-arc oxidation. The application is used for the preparation of the tin dioxide negative material.

This invention discloses a method for preparing tin dioxide powder by freeze-drying to inhibit tin hydroxide agglomeration. The method involves adding a tin source solution (36-54 g / L) and a precipitant solution (5-30 g / L) at a mass ratio of 1:0.1-0.25 under constant temperature and magnetic stirring. The precipitant solution is then added dropwise to the tin source solution, reacting to form tin hydroxide colloid. After static aging, the colloid undergoes rapid cryogenic freezing to instantly freeze it into an ice state. The ice-state colloid is then subjected to low-temperature vacuum sublimation drying to obtain loose tin hydroxide dry powder. The dry powder is then calcined to obtain tin dioxide powder. This invention fundamentally eliminates the agglomeration of tin dioxide powder, resulting in tin hydroxide dry powder with an agglomeration rate of less than 10% and a purity of over 99.9%, providing a high-quality precursor for high-performance electronic-grade tin dioxide.

The present invention discloses a H2 sensor material based on SnO2-doped graphene aerogel and a preparation method. The material comprises mixing graphene oxide with N,N-dimethylformamide and water to form a mixed solution, adding the mixed solution to a tin salt solution, performing a solvothermal heat treatment, and then calcining the solution in a muffle furnace. The present invention dopes the graphene aerogel with SnO2 nanoparticles. The graphene aerogel structure modifies the operating characteristics of the tin dioxide material, resulting in a sensor material with high gas sensitivity, good selectivity, and stability. This reduces the sensor's operating temperature and device power consumption, resulting in ultrahigh sensitivity, anti-interference performance, and good resistance to electrolyte corrosion. The material has broad application prospects in the future field of thermal runaway early warning technology for lithium-ion batteries.

To provide a gas sensor with good response characteristics to gas (low-concentration gas in particular).SOLUTION: A gas sensor is provided, comprising a base material, first and second electrodes provided on a surface of the base material, and a gas sensing layer connected to the first and second electrodes and provided with a Ni-containing SnO2 nanosheet comprising an SnO2 nanosheet and Ni contained in the SnO2 nanosheet.SELECTED DRAWING: Figure 7

This disclosure provides techniques for detecting / inhibiting corrosion of in distribution / recirculation service lines and for using tin dioxide as a surfactant to coat at-risk piping surfaces. For example, disclosed techniques can be used to correlate corrosive conditions with fluid type, source and other environmental parameters, and to treat piping so as to insulate corroding areas. A stannous dosing system, and optionally, associated downstream filtration, can be used to efficiently deliver tin throughout piping surfaces at interest, and thereby facility local tin dioxide surfactant buildup to target thicknesses, at difficult to reach locations. In one embodiment, disclosed systems can be used to build a correlation database that can be used in the automated control of systems taught herein.

A kind of anti-spark ceramic and its body glaze, preparation method, use and ceramic tile, the body glaze is characterized in that, by mass fraction, its raw materials include: 3-12 parts of light calcium powder, 1-10 parts of magnesium oxide, 8-17 parts of dolomite powder, 6-12 parts of sodium sand, 6-12 parts of potassium sand, 0.5-6 parts of alumina and 10-25 parts of pottery clay, can also add tin dioxide, diantimony trioxide and zinc oxide as slurry conductive nanomaterial, can adjust both anti-spark property and anti-static property of ceramic to the best interval simultaneously.Anti-spark ceramic is provided with a body glaze layer prepared from the above-mentioned body glaze of anti-spark ceramic.The preparation method is used to prepare the above-mentioned anti-spark ceramic.The present application can solve the problem of friction impact sparking of other floor materials in the prior art, and also solve the problem that the anti-spark performance and anti-static performance of ceramic cannot be simultaneously achieved.

This invention discloses a high-temperature conductive graphene solution and its preparation method, comprising the following components by weight: 1800-2000 parts of a dispersion containing 3-5 nm graphene quantum dots, wherein the quantum dot content is 5-10 wt%; 450-510 parts of tin dioxide with a particle size ≤0.2 μm; 15-20 parts of ammonium tungstate and 15-20 parts of lanthanum oxide; 30-40 parts of manganese chloride tetrahydrate, 20-30 parts of nickel chloride, and 20-30 parts of copper chloride; 8000-10000 parts of a solvent system, wherein deionized water ≤4000 parts, anhydrous ethanol ≤5000 parts, isopropanol ≤100 parts, and n-butanol ≤50 parts; 800-1000 parts of tri-n-butyltin hydride and 100-300 parts of citric acid. Due to the adoption of the above technical solutions, this application has achieved breakthroughs in the stability of conductive networks through quantum dot bridging mechanisms; the standard deviation of electron migration path length has been reduced from 1.2 μm to 0.08 μm; the heterojunction interface has been optimized and a Type-II band structure has been formed, resulting in an 82% reduction in contact resistance.

The invention discloses a method for preparing a gradient tin dioxide film based on a chemical bath method, which comprises the following steps: S1, mixing urea, mercaptoacetic acid, hydrochloric acid and stannous chloride to obtain a clear chemical bath deposition solution; s2, a substrate is immersed in the chemical bath deposition solution prepared in the step S1 for soaking deposition, and then washing, annealing and blow-drying are conducted; and S3, the substrate is immersed in the chemical bath deposition solution prepared in the step S1 again for secondary chemical bath deposition, then washing, annealing and blow-drying are conducted, and the gradient tin dioxide thin film can be formed on the substrate. The prepared tin dioxide film has the advantages of being more uniform, low in resistivity, high in migration rate, high in visible light range transmissivity and the like; the preparation process can be repeated, and no suspended matter is generated in the deposition process. The tin dioxide thin film prepared by the method is applied to the perovskite solar cell, and the photoelectric conversion efficiency of the perovskite solar cell can be effectively improved.

The invention relates to a modified SnO2 sol, a perovskite solar cell and a preparation method, and the preparation method comprises the steps: adding an alkali source into a conventional SnO2 sol, and then carrying out ultrasonic dispersion to obtain the modified SnO2 sol; the ultrasonic treatment can reduce the roughness of an electron transport layer material and improve the conductivity of a stannic oxide transport layer, the agglomeration of a SnO2 colloidal solution can be effectively blocked due to the combination of hydroxyl radicals obtained after ultrasonic treatment and Sn atoms, stannic oxide can form a double-electrode layer under the action of an alkali source in the ultrasonic process, and thus the conductivity of the SnO2 transport layer can be effectively improved due to electrostatic repulsion. The SnO2 sol can stably exist in a solution, so that the reservoir stability of the SnO2 sol is improved; besides, by adding NaClO to passivate oxygen vacancies on the surface, generation of the oxygen vacancies is reduced, Cl ions can be combined with the oxygen vacancies, diffusion of iodine from perovskite to an ETL layer can be inhibited, and the degradation level of a perovskite material at an interface is effectively reduced.

The invention discloses a tin-based alloy catalyst and a preparation method and application thereof, and belongs to the technical field of catalysts. The catalyst comprises a carrier and an active component, the carrier comprises tin dioxide or metallic tin, and the active component is selected from at least one of transition metal and main group metal with catalytic action; the mass percent of the active component in the catalyst is 0.01%-30%, preferably 0.01%-10%. The active component is selected from metal with a catalytic action and an eutectic point of 500 DEG C or below. According to the tin-based alloy catalyst, high conductivity and an adjustable electronic structure promote efficient electron transmission, reaction kinetics is remarkably improved, and meanwhile the tin-based alloy catalyst shows excellent chemical stability in the catalysis process. The tin-based alloy catalyst provided by the invention is simple to prepare, low in cost, environment-friendly, high in conductivity and excellent in stability, and shows strong industrialization potential in the field of clean energy.

This invention discloses a method for preparing doped tin dioxide nanocrystals that can be highly dispersed in any water-to-alcohol ratio. The preparation method includes the following steps: (1) adding trimethylamine oxide to an aqueous solution containing tin halide to produce a white precipitate and stirring; (2) subjecting the mixture obtained in step (1) to a hydrothermal reaction at 120–200°C for 3–24 h, separating the solid and liquid phases after the reaction, and dispersing the solid phase in pure water, pure alcohol, or a water-to-alcohol mixture with any water-to-alcohol ratio to obtain a halogen-doped tin dioxide dispersion; (3) adding an organic base stabilizer to the halogen-doped tin dioxide dispersion and mixing to obtain halogen-doped tin dioxide nanocrystals that are highly dispersed in pure water, pure alcohol, or a water-to-alcohol mixture with any water-to-alcohol ratio. The preparation method of this invention is simple and inexpensive, broadens the application field of tin dioxide, and has important application value.

Provided are: oxide colloidal particles which contain rutile-type titanium oxide as a main component and in which the formation of anatase-type titanium oxide is effectively suppressed; a sol containing the oxide colloidal particles; and a method for producing the oxide colloidal particles. The problem is solved by oxide colloid particles (A) comprising Ti and Sn and having an average primary particle diameter of 5-300 nm and / or a primary particle diameter of 5-300 nm in terms of both D10 and D90 in the number-based cumulative particle size distribution, wherein the numerical value of (rutile-type tin dioxide content) / (rutile-type titanium oxide content) (mass ratio) calculated by the method below is 0.3-3.5% when expressed as a percentage: (rutile-type tin dioxide content) / (rutile-type titanium oxide content) (mass ratio) = ((intensity of rutile-type tin dioxide diffraction lines in a diffraction pattern obtained by powder X-ray diffraction in a 2θ range of 20.0°-80.0°) / 9.63) / ((intensity of rutile-type titanium oxide diffraction lines in the diffraction pattern obtained by powder X-ray diffraction in the 2θ range of 20.0°-80.0°) / 3.27).

The invention discloses an electrocatalyst for reducing nitrate into nitrogen under a strong acid condition and a preparation method thereof.The electrocatalyst is a stannic oxide material rich in polycrystals, the specific component of the material is SnO2, and the preparation method comprises the steps that stannous chloride and ammonium fluoride are subjected to a hydrothermal method to obtain a stannic oxide precursor; and treating the precursor under an acidic condition by using a pulse current method. The problem that the efficiency is low in the electro-catalysis nitrate pollutant removal process is solved. And meanwhile, the electrocatalyst can keep relatively high stability under a strong acid condition, does not generate nitrite, and has certain commercial and practical application values.