112 results about "Nano clusters" patented technology

Disclosed are a method for fabricating nanopowders, nano ink containing the nanopowders and micro rods, and nanopowders containing nanoparticles, nano clusters or mixture thereof, milled from nano fiber composed of at least one kind of nanoparticles selected from a group consisting of metal, nonmetal, metal oxide, metal compound, nonmetal compound and composite metal oxide, nano ink containing the nanopowders and microrods, the method comprising spinning a spinning solution containing at least one kind of precursor capable of composing at least one kind selected from a group consisting of metal, nonmetal, metal oxide, metal compound, nonmetal compound and composite metal oxide, crystallizing or amorphizing the spun precursor to produce nano fiber containing at least one kind of nanoparticles selected from a group consisting of metal, nonmetal, metal oxide, metal compound, nonmetal compound and composite metal oxide, and milling the nano fiber to fabricate nanopowders containing nanoparticles, nano clusters or mixture thereof.

The invention discloses a carbon quantum dot/aurum cluster ratiometric fluorescent probe for detection of cadmium ion and ascorbic acid. A preparation method comprises the following steps: preparing CQDs (Carbon Quantum Dots) from alanine and histidine through a one-step hydrothermal method; performing amino-functionalization on the CQDs by using 3-aminopropyltriethoxysilane, wherein the CQDs which are subjected to the amino-functionalization serve as a reference chromophore; reducing chloroauric acid through sodium borohydride by taking 11-sulfydryl undecanoic acid as a surfactant to obtain MUA-modified AuNCs (Aurum Nano Clusters), wherein the MUA-modified AuNCs serve as a main fluorophore of the ratiometric fluorescent probe; finally, coupling the CQDs and the AuNCs through an amidation reaction to obtain the CQDs/AuNCs ratiometric fluorescent probe. On the basis of static quenching and inter-filtering effects, the fluorescence of the CQDs/AuNCs can be quenched by Cd<2+>; the invention discloses the application of the CQDs/AuNCs ratiometric fluorescent probe in Cd<2+> detection. The fluorescence of the CQDs/AuNCs which is quenched by the Cd<2+> can be recovered by the ascorbic acid, so that the ratiometric fluorescent probe can also be used for the detection of AA (Ascorbic Acid). The ratiometric fluorescent probe disclosed by the invention has the lower detection limit of 32.5 nM to the Cd<2+>, has the lower detection limit of 0.105 muM to the AA, and has an application value in the detection of the cadmium ion and the ascorbic acid.

The invention discloses a nano-grade composition, a preparation method thereof, and an application thereof as an electrochemical catalyst. The nano-grade composition provided by the invention is basically composed of a melamine derivative, a carbon material, and transition metal or transition metal alloy nano-cluster. The carbon material comprises at least one selected from conductive carbon black, activated carbon, carbon nano-horn, N-doped carbon nano-horn, carbon nano-tube, graphene, graphite and carbon fiber material. The metal nano-cluster is at least one selected from Pt, Ru, Pd, Rh and Ir nano-clusters. The alloy nano-cluster is nano-cluster formed by more than two elements selected from Pt, Ru, Pd, Rh, Ir, Fe, Cu and Ni. The mass percentage content of the transition metal or alloy nano-cluster is 0.1-90%. The size of the transition metal or alloy nano-cluster is 0.5-10nm. As a fuel cell catalyst, the nano-grade composition provided by the invention has excellent electrocatalytic activity upon reactions such as oxygen reduction and methanol oxidation.

A twin-wire arc deposition method for depositing a nano-structured catalyst coating onto a solid electrolyte membrane or an electrode substrate from a precursor catalyst material selected from the group consisting of a metal, metal alloy, metal compound, and ceramic material. The method includes the steps of (a) providing an ionized arc nozzle comprising two consumable electrode and a working gas flow to form an ionized arc between the two electrodes, wherein the consumable electrodes provide the precursor catalyst material vaporizable therefrom by the ionized arc; (b) operating the arc nozzle to heat and at least partially vaporize the precursor catalyst material for providing a stream of nanometer-sized vapor clusters of the precursor catalyst material into a chamber in which the membrane or the electrode substrate has been placed; and (c) introducing a stream of a carrier gas into the chamber to impinge upon the stream of precursor vapor clusters to produce depositable nano clusters which are carried by the carrier gas to deposit onto a first side of the membrane or the electrode substrate for forming the nano-structured catalyst coating. Such a catalyst-coated membrane or electrode can be incorporated as a part of a fuel cell.

The invention relates to a preparation method of molecular sieves, in particular to a preparation method of mesoporous-microporous titanium silicalite molecular sieves. The method includes: uniformly mixing tetrapropylammonium hydroxide, tetrabutyl titanate, tetraethyl orthosilicate and deionized water in the mass ratio of 1:20-90:8:1500, reacting at the constant temperature of 35 DEG C prior to mixing with polymethyl vinyl fluoride, and crystallizing for 1 hour at the temperature of 140 DEG C to obtain nano-clusters; and mixing hexadecyl trimethyl ammonium bromide, the deionized water, ammonia water 25% in concentration and the polymethyl vinyl fluoride, crystallizing for 72 hours at the temperature of 120 DEG C to obtain a product, and subjecting the product to suction filtration, washing, drying at the room temperature and roasting for 4 hours at the temperature of 500 DEG C so that the mesoporous-microporous titanium silicalite molecular sieves are obtained. Experimental results show that the mesoporous-microporous titanium silicalite molecular sieves prepared by the method are large in specific surface area, and micropores are reserved in pore walls of mesopores; primary and secondary building units of TS-1 molecular sieves are successfully introduced into the pore walls of the mesoporous molecular sieves; and the mesoporous-microporous titanium silicalite molecular sieves prepared by the method has good selectivity on generation of styrene oxide in epoxidation reaction of styrene.

Size-controlled immobilization of metal nano-clusters onto particles or nanoparticles is achieved using a polyol process. Polyol processing makes it possible to use thiol groups as a chemical protocol to functionalize the surface of particles, such as silica and polystyrene nanoparticles. Metal nano-clusters, such as silver, gold, platinum and palladium, nucleate and grow on the surface of the particles. The metal nano-clusters may be synthesized in a one-pot process from metal salts, nitrates, nitrites, sulfates, sulfites and the like. Any source of metal ions compatible with the polyol suspension and selected particles may be used. The size of immobilized metal nano-clusters may be controlled by additions of a poly(vinylpyrrolidone) or other polymer capable of regulating the metal ion reduction and nucleation process and by controlling concentration of metal ions, the nucleation and/or growth temperatures, and processing time.

The invention provides application of thiol-polyethylene glycol in preparation of water-soluble gold nano-clusters. The thiol-polyethylene glycol is shown as the following formula (I): HS-(CH2)m-(OCH2CH2)<n>-X. The water-soluble gold nano-clusters prepared by utilizing the thiol-polyethylene glycol have the advantages of being high in purity (being capable of stably existing in hyperpure water, high in stability (being stable in different pH values and different buffering solution systems), high in water solubility, supportive of surface chemical modifying, supportive of targeting, simple to synthesize and the like.

The invention provides a paramagnetic metal complex functionalized fluorogold nano-cluster magnetic resonance and fluorescence imaging contrast agent. The invention relates to the field of magnetic resonance imaging and fluorescence imaging contrast agents. With the contrast agent provided by the invention, problems of existing contrast agents of low relaxation efficiency, high toxicity, low tissue organ selectivity and fast in-vivo metabolism can be solved. According to the invention, ethylenediaminetetraacetic acid (EDTA) or diethylene triaminepentaacetic acid (DTPA) are connected to folic-acid-modified bovine serum albumin fluorogold nano-clusters through amide bonds; and EDTA or DTPA is respectively coordinated with paramagnetic metal ions, such that the complex is obtained. With the contrast agent provided by the invention, the relaxation efficiency can reach 23.7mM<-1>*s<-1>. The contrast agent has an advantage of low toxicity. According to the invention, high spatial resolution of magnetic resonance imaging and high sensitivity of fluorescence imaging are combined. Therefore, the contrast agent provided by the invention can be used in magnetic resonance imaging and fluorescence imaging.

The invention discloses a method for a novel nano precious metal particle modified tin dioxide gas sensitive material. The preparation method for the nano precious metal particle modified tin dioxide gas sensitive material comprises the following steps of: adding a small quantity of other elements serving as performance tuning elements into raw materials of precious metal powder (two or more types of Ag, Au, Pt, Ru, Rh, Pd, Ir and Re), tin powder or alloy powder of the precious metals and tin, wherein the mass fraction ratio of the precious metals to the tin is controlled to be between 2 and 10 percent; performing mechanical alloying in a low-temperature ball mill, wherein the prepared precious metals are enwrapped by the tin powder, and formed nano-clusters are uniformly distributed in powder; pressing the prepared compound powder; performing oxygen atmosphere sintering at a certain temperature; and finishing reactive synthesis of oxides by controlling the process condition. The prepared precious metals are distributed in a tin dioxide target material in the form of nano particles, and the previous metal nano particles prepared by sputtering or depositing are uniformly distributed on a tin dioxide gas sensitive thin film. The novel gas sensitive material prepared by the method has high gas sensitive comprehensive performance, low cost, wide detection of harmful gases and long service life.

The invention provides a preparation method of an array fluorescent nano-cluster sensor and an application of the array fluorescent nano-cluster sensor to metal ion recognition. The preparation method comprises steps as follows: 1), seven fluorescent nano-clusters required by the array fluorescent nano-cluster sensor are synthesized; 2), the array fluorescent nano-cluster sensor is prepared by means of the seven fluorescent nano-clusters. A method for applying the array fluorescent nano-cluster sensor to metal ion recognition comprises steps as follows: different samples containing metal ions are mixed with the array fluorescent nano-cluster sensor; fluorescence intensity signals of the seven nano-clusters, responding to the samples, in the array fluorescent nano-cluster sensor are read; the fluorescence response signals of the seven nano-clusters responding to the samples are taken as array signals to recognize the samples; finally, a practical water sample is recognized by means of a nano-cluster array. Experiments prove that the method is convenient and efficient, metal ions in the samples can be quickly responded, and the samples containing the metal ions are quickly recognized according to the recognition response signals of the nano-cluster array responding to the metal ions.

The invention uses a metal nano-cluster novel light-emitting material to act as an innovative LED packaging material so as to realize construction of high-performance LEDs, specifically relates to LED construction of a novel packaging material based on a metal nano-cluster assembly structure which is controllable in light color, strong in fluorescence and high in stability, and particularly relates to a method for preparing a high-performance fluorescent metal nano-cluster assembly structure quickly, simply and safely in a high-yield mode. Pre-preparation of metal nano-clusters is directly reduced and stabilized by hydrosulfuryl molecules, nano-cluster assembly structures with different light colors are realized through regulating the type of metal sources, the type of the hydrosulfuryl molecules, the feeding proportion of reactants, the reaction time, the temperature and the like, and finally, the nano-cluster assembly structures are applied to an LED packaging material so as to realize construction of a high-performance LED light source. The method provided by the invention is simple and convenient to operate in the preparation, assembling and packaging process and small in dangerousness, and has good experimental repeatability.

The invention discloses a mercury ion detection method. The mercury ion detection method comprises the following steps: adding a solution to be detected, which possibly contains Hg<2+>, Tween-20, a sodium citrate buffering solution, hydrogen peroxide and a TBM solution, into a double-metal nano cluster solution, and mixing for reacting; and detecting the concentration of Hg<2+> in the solution to be detected by observing a light absorption value of a visible light wave band of a mixing reaction system. The mercury ions (Hg<2+>) are detected colorimetrically by simulating peroxidase based on DNA-Ag/Pt nano clusters; a linear range of detection is 10.0nM-200nM and the sensitivity can reach 3.0nM; and the mercury ion detection method has the advantages of simplicity, convenience and rapidness, low cost, high stability and the like, and can be applied to detection of Hg<2+> in samples of environments, foods and the like.

The invention discloses preparation of fluorogold nano-clusters and application of the fluorogold nano-clusters to tetracycline and copper fluorescent probes. The fluorogold nano-clusters (Au NCs) aresynthesized with a one-step method from casein separated from milk and carbon quantum dots as a stabilizer and a reducer for synthesis of the Au NCs. The Au NCs perform emission three times at 433 nm, 702 nm and 1052 nm under the excitation wavelength of 350 nm, tetracycline has a linear quenching effect at 702 nm, Cu<2+> is added to an Au NCs system after quenching, fluorescence recovers, and fluorescence intensity at 1052 nm is almost not affected in the overall process; tetracycline is added to the Au NCs, observation is carried out under a UV (ultraviolet) lamp with wavelength of 365 nm,red fluorescence of the Au NCs changes into yellow fluorescence, and after addition of Cu<2+>, the yellow fluorescence disappears gradually and the red fluorescence recovers gradually. Therefore, a near-infrared ratio fluorescence switch for tetracycline and Cu<2+> and UV visual dual-signal detection are established. The method has the advantages of adopting a fluorescence spectrum in a near infrared region and being small in interference, high in specificity and detection sensitivity, convenient to operate and capable of detecting tetracycline and Cu<2+> simultaneously.

The invention discloses a high efficient metal-semiconductor composite photocatalyst for photocatalytic synthesis for preparing ammonia gas from nitrogen and hydrogen, and a preparation method and applications thereof, and belongs to the technical field of catalysis of ammonia synthesis. Super para-magnetic dual-metal (iron-platinum, iron-palladium, iron-gold, or iron-nickel) nano clusters are loaded on semiconductor nitrides, semiconductor oxides, and semiconductor silicon (g-C3N4, ZnO, MoO2, or Si) to obtain the composite photocatalyst with high catalytic activity. The photocatalytic can catalyze synthesis of ammonia namely reactions between N2 and H2 at a room temperature under a normal pressure in the presence of light. The provided novel photocatalyst can be used to replace a conventional catalyst, NH3 can be synthesized from N2 and H2 under milder conditions, the NH3 synthesis cost is reduced, and thus the energy consumption and environmental pollution are effectively reduced.

The invention discloses an application of an electrochemiluminescence biosensor based on cytosine (C)-containing cyclic DNA sequences where in-situ reduced Ag nano-clusters are enriched as signal probes and adopting dual amplification strategy to detection of target thrombin. According to the technical scheme, DNA cleavage enzyme with hairpin DNA recognition capability and catalysis effect is designed, when target thrombin exists, hairpin DNA is opened, and substrate DNA is cleaved under the action of Zn<2+>; a large quantity of cytosine (C)-containing cyclic DNA sequences are aggregated through HCR (hybridization chain reaction), in-situ reduction of AgNO3 is performed on the electrode surface by NaBH4, a large quantity of Ag nano-clusters are formed, and the electrochemiluminescence biosensor with dual amplification effect is prepared. The sensor is subjected to luminescence detection, and a linear relation is formed between light-emitting signals and concentration of a to-be-testedsample. The Ag nano-cluster signal probes and the DNA dual amplification technology are combined for rapid and high-sensitivity detection of thrombin, and the electrochemiluminescence biosensor has great application potential in early clinical analysis and detection.

The invention relates to nano-cluster-strengthened iron-base superalloy, which comprises the following components: Fe-(13-15)Cr-(2.5-3.5)W-(0.35-0.6)Ti-(0.2-0.6)Y-(0.05-0.20)O, wherein Y and O are used as alloy elements, O is introduced into the alloy as an alloy element, O element and pure metal Y replace Y2O3 particles added directly to serve as reinforced mass point, gas-atomized alloy powder replaces mechanically-alloyed powder so as to more accurately control oxygen content, and the alloys in different batches have uniform performance and good repeatability. The final product can be effectively controlled to form nano clusters or nano oxides in dispersed distribution; and the produced alloy has high purity and no alloy pollution problem caused by mechanically-alloyed powder; and the oxide is finer and disperses evenly. The production method provided by the invention has simple process, high production efficiency and low cost, can be used for preparing large size material, and is favorable for large-scale production and application.

The invention relates to the technical field of nano materials, and in particular to a method for selective sensitive mercury ion detection based on a gold nano-cluster fluorescence ratio detection test strip. The method comprises the following steps: firstly, preparing gold nano clusters with two different fluorescence emissions, that is, a bovine serum albumin coated gold nano-cluster (BSA-Au NCs) and cysteine coated gold nano-cluster (Cys-Au NCs); according to an appropriate proportion, concentration and pH conditions, preparing a fluorescence ratio probe, wherein the detection range is 50 nM-3 [mu]M, the minimum price detection limit is 9 nM, and the fluorescence ratio probe is as shown in figure 1 in the specification; finally preparing the fluorescence ratio detection test strip. By adopting the method, the fluorescence ratio detection test strip is prepared under gentle conditions and is applied to detection on mercury ions in an actual water sample.

The invention belongs to the technical field of preparation of composite materials and discloses a ferric oxide/bismuth oxybromide composite material and a preparation method and application thereof. The ferric oxide/bismuth oxybromide composite material is formed by ferric oxide nano-clusters depositing on the surfaces of bismuth oxybromide nano-sheets. The preparation method comprises the steps of adding an alkali solution into a ferric nitrate solution to obtain a ferric hydroxide colloidal solution, adding a KBr solution into a bismuth nitrate solution, performing mixing to obtain a mixed solution, dropwise adding the ferric hydroxide colloidal solution into the mixed solution and performing hydrothermal reaction to obtain the ferric oxide/bismuth oxybromide composite material. The preparation method has the advantages of being simple in preparation process and low in cost, having very good environmental protection benefits and the like, the prepared composite material has excellent photocatalytic performance and is widely applied to the field of photocatalytic degradation of dye wastewater, and the higher catalytic efficiency can be obtained.

The invention discloses a method for purifying copper nano-clusters. The method comprises the following steps: 1) dissolving BSA in a solution so as to prepare a clear and transparent solution; 2) adding copper ions into the solution prepared in the step 1) according to a weight ratio of BSA to Cu<2+> of (10-40):(1-10), and uniformly mixing; 3) under the action of stirring, adding sodium hydroxide into the solution obtained in the step 2), at the same time adjusting the pH value of the solution, and stirring at 37-60 DEG C so as to obtain copper nano-cluster stoste; 4) adding HNO3 into the copper nano-cluster stoste prepared in the step 3), and adjusting the pH value of the copper nano-cluster stoste to be 3-6 so as to generate copper nano-cluster precipitate; 5) centrifuging the copper nano-cluster precipitate generated in the step 4), separating and washing; 6) dispersing the copper nano-cluster precipitate washed in the step 5) into a sodium hydroxide solution so as to prepare a clear and transparent solution, thereby obtaining the copper nano-clusters. The method has the advantages that as a copper ion-containing substance is taken as a main material, and BSA or DNA and glutathione are taken as auxiliary materials to prepare the copper nano-clusters, the method is simple and environment-friendly in operation and low in cost.

The invention discloses a preparation method of an inorganic nanocomposite FexOy/M. The preparation method includes: mixing precursor solution of M to prepare Fe3O4 nano clusters and proper alkali solution, performing hydrothermal treatment at a certain temperature for a certain time to obtain a product, and separating-cleaning, drying the product to obtain the inorganic nanocomposite FexOy/M; wherein the FexOy is Fe3O4 or Fe2O3, M is one or mixture of two of NiO, BiFeO3, La(OH)3, Cd(OH)2, CuO, and FeOOH. The preparation method is simple, universal, and a huge progress, and breaks through the limit that composite with one component or inorganic nanocomposite with one morphology can be prepared in the prior art. The nanocomposite prepared by the method has application prospect in fields such as nano catalysis, solar energy conversions, lithium ion batteries, and gas sensitive devices.

The invention relates to pressureless sintered conductive silver paste which comprises: 70 -85% of silver powder, 5 -20% of solvent, 0.1 -2% of a dispersing agent and 0.5 -5% of an organic carrier, wherein the silver powder is composed of micron silver powder and nano silver powder. The micro-silver powder is subjected to surface modification, and silver nano-clusters are formed on the surfaces. The characteristics of low-temperature sintering of the nano-clusters are utilized, the sintering of the nano-particles and the connection of the micron-silver powder are promoted, and the low-temperature sintering compactness of the conductive silver paste is improved. The bonding and interconnection of a chip and a metal layer on the surface of a substrate are realized. The conductive silver paste prepared by the preparation method disclosed by the invention has the characteristics of high temperature resistance, high heat conductivity and high bonding property, and the reliability of the packaging device can be remarkably improved. The pressureless sintered conductive silver paste and the preparation method thereof are suitable for bonding and heat dissipation of a third-generation wide-gap semiconductor chip.

The invention discloses an AuNCs@521-MOF (metal-organic framework) nano-sheet compound, a preparation method thereof and an application. The AuNCs@521-MOF nano-sheet compound comprises a plurality of aggregates formed by two-dimensional zirconium-based metal-organic framework nano-sheets and a plurality of Au nano-clusters distributed in the aggregates. The 2D (two-dimensional) AuNCs@521-MOF nano-sheet compound has high specific surface area, good physicochemical stability and electrochemical activity and high biological affinity for phosphate groups of biological molecules. The invention further discloses an electrochemical aptasensor. The electrochemical aptasensor can simply and conveniently detect cocaine and has the advantages of high selectivity, good repeatability and stability, simplicity in operation and the like, the AuNCs@521-MOF nano-sheet compound can build a new platform for bio-sensing, and the application range of MOFs materials is widened.

The invention provides a metal nano-cluster doped memristor and a method for preparing the same, and relates to the technical field of microelectronics. The metal nano-cluster doped memristor comprises an upper electrode, a resistance random layer and a lower electrode. The resistance random layer is positioned between the upper electrode and the lower electrode and is a thin film made from resistance random materials, and metal nano-clusters are doped in the thin film. The method includes S1, cleaning the lower electrodes; S2, forming the resistance random layer on a surface of the cleaned lower electrode in pulling film coating modes; S3, growing the upper electrode on the resistance random layer by the aid of magnetron sputtering processes. The metal nano-cluster doped memristor and themethod have the advantages that the metal nano-clusters are doped into thin film materials made from the resistance random materials to prepare corresponding metal nano-cluster doped composite thin films, effects of reinforcing local electric fields can be realized by the metal nano-clusters under the effects of electric fields, and the resistance transformation characteristics can be improved; the metal nano-cluster doped memristor is stable in resistance random memory property and high in switch speed, and a foundation can be laid for designing and further developing memristors.