46 results about "Gold nanocrystal" patented technology

The invention relates to a method for preparing a sub-nanometer gold cluster molecule. The purification of the prior part is complex. The method of the invention firstly uses chloroauric acid as raw material and adopts a solution method for synthesizing a gold nanometer crystal solution. Then, the gold nanometer crystal solution and amine solution with the molar concentration of 1mM-10M are mixed and react for more than 30min. After the reaction is finished, the centrifugal separation is carried out on the solution to obtain sub-nanometer gold cluster molecular solution. The sub-nanometer gold cluster molecule obtained by the method is monodispersed Au8 cluster molecule. Only common centrifugation is required for separating other impurities. The purification mode is simple.

The invention discloses a preparation method of nano-sized gold/titanium dioxide compound mesoporous microspheric photocatalyst, and belongs to the technical field of catalysts. The preparation method comprises the following steps: mixing monodisperse oil-phase titanium dioxide nanocrystal and a monodisperse oil-phase gold nanocrystal in a mass ratio of gold to titanium dioxide of (0.5-15): 100; adding the mixture into an aqueous solution in which sodium dodecyl sulfate is dissolved; crushing the mixture by using an ultrasonic crushing device to obtain a microemulsion; completely evaporating an organic solvent in an oil bath at 50-80 DEG C, centrifugating, eluting and drying; and calcining dried powder to obtain the gold-doped nano-sized titanium dioxide mesoporous sphere. Components of the prepared nano-sized gold/titanium dioxide compound mesoporous microsphere keep respective microscopic shapes; and the two nanocrystals are assembled by the microemulsion method to form a special mesoporous structure, so that the specific surface is large, the mass transfer is easy and the photocatalysis easily occurs on the surface of the catalyst.

The present disclosure describes a method and an apparatus for making nanomaterials. In particular, the present innovation provides an apparatus that can be used to produce nanocrystals and/or nanorods of noble metals. The disclosure also provides methods that can be advantageously used to produce gold nanocrystals/nanorods with aspect ratios higher than 4.0.

The invention discloses a preparation method of a concave cuboid Pt-Ir alloy nanocrystal catalyst having a high-index crystal surface structure, and belongs to the technical field of preparation of afuel cell catalyst. The Pt-Ir alloy catalyst exists in a green and novel non-aqueous medium, namely a deep-eutectic solvent, and a concave cuboid Pt-Ir alloy nanocrystal with a {hk0} high-index crystal surface-structure surface is prepared by employing an electrochemical cyclic voltammetry method under a condition without any surfactant. The surface of the concave cuboid Pt-Ir alloy nanocrystal catalyst is a high-index crystal surface, the concave cuboid Pt-Ir alloy nanocrystal catalyst is provided with an opening surface structure, a large amount of active sites are provided, the poison capability of an intermediate body resistant to CO and the like is remarkably improved by a dual-functional mechanism of an alloy surface structure, and the concave cuboid Pt-Ir alloy nanocrystal catalysthas excellent electrocatalytic performance on fuel micromolecules such as formic acid, methyl alcohol and ethyl alcohol.

The invention discloses a dog-bone-shaped gold nanocrystal preparing method. The dog-bone-shaped gold nanocrystal preparing method includes the steps of adding an aqueous cetyl ammonium bromide solution in an aqueous chloroauric acid solution, adding a silver nitrate solution, mixing fully, adding ascorbic acid, and mixing with stirring to obtain a growth solution; mixing the aqueous cetyl ammonium bromide solution with the aqueous chloroauric acid solution, adding a sodium borohydride solution, and stirring until the mixed solution turns into claybank so as to obtain a seed solution; adding the seed solution in the growth solution, mixing with stirring, and standing for growing to obtain dog-bone-shaped gold nanocrystals. The dog-bone-shaped gold nanocrystal preparing method has the advantages of easily-available raw materials, simplicity in operation, good repeatability, low cost, high controllability and capabilities of obtaining stable and efficient dog-bone-shaped gold nanocrystal and obtaining different sizes of dog-bone-shaped gold nanocrystals by means of reacting condition adjustment, has important application value for synthesis of large-scale dog-bone-shaped gold nanocrystals and is of important guiding significance to gold nanocrystal preparing method research.

The invention discloses a preparation method of an Au-Cu alloy nanocrystal and the Au-Cu alloy nanocrystal prepared by the preparation method, and the pentagram-shaped Au-Cu alloy nanocrystal is synthesized by a mild aqueous-phase synthesis method, is controllable in size, and has pentagonal symmetry. The method is as follows: a CuCl2 aqueous solution, a HAuCl4 aqueous solution and a glucose solution are added into a glass bottle containing hexadecylamine (HDA) and deionized water, the glass bottle is placed on a magnetic stirrer for stirring at room temperature overnight. At this time, each of the reactants in the bottle is evenly dispersed, and is transferred into 100 DEG C oil bath for 30 min of reaction. As the reaction proceeds, the solution turns from yellow green to dark brown, so far, the pentagram-shaped Au-Cu alloy nanocrystal is synthesized, the pentagram-shaped Au-Cu alloy nanocrystal is prepared by the aqueous-phase synthesis method, the system is mild and clean, the experimental operation is simple wide, and the application prospect is wide.

The invention belongs to the field of chemical engineering, and provides a preparation method for special-shaped gold nanocrystals and application on detection of tripolycyanamide by using surface enhanced Raman scattering. The preparation method comprises the following steps of preparing gold by using trisodium citrate as a stabilizer; using hexadecyl trimethyl ammonium bromide, a chloroauric acid, silver-bearing salt liquor and an ascorbic acid as growth-promoting media; preparing nanogold by using an organic acid as an additive; and performing resolution after centrifugal separation. The special-shaped gold nanocrystals are used for detecting Raman spectra of standard liquor or sample liquor of the tripolycyanamide. The nanogold is prepared by using a seed induction multi-step growing method, an additive containing benzene ring is added in the nanogold, and the use level of the hexadecyl trimethyl ammonium bromide is reduced, so that the cost is obviously reduced, and purification time and purification steps are reduced. The prepared nanogold has an angular structure, and can be used for detecting an enhancement substrate of trace tripolycayanamide by using surface enhanced Raman scattering; and compared with an HPLC (high performance liquid chromatography) method, the nanogold has the advantages that the analyzing time is short, the cost and the reproducibility are high, and the nanogold can be widely applied to quickly detecting the tripolycyanamide in dairy products.

Systems and methods are provided for an on-chip decoupling device and method. One aspect of the present subject matter is a capacitor. One embodiment of the capacitor includes a substrate, a high K dielectric layer doped with nano crystals disposed on the substrate, and a top plate layer disposed on the high K dielectric layer. According to one embodiment, the high K dielectric layer includes Al₂O₃. According to other embodiments, the nano crystals include gold nano crystals and silicon nano crystals. One capacitor embodiment includes a MIS (metal-insulator-silicon) capacitor fabricated on silicon substrate, and another capacitor embodiment includes a MIM (metal-insulator-metal) capacitor fabricated between the interconnect layers above silicon substrate. The structure of the capacitor is useful for reducing a resonance impedance and a resonance frequency for an integrated circuit chip. Other aspects are provided herein.

Provided is a synthetic method of water-solubility biocompatibility monodisperse spherical gold nanometer crystals. The synthetic method of the water-solubility biocompatibility monodisperse spherical gold nanometer crystals comprises the following steps (1) using ultra-pure water to prepare a sodium citrate solution, a chloroauric acid solution, a silver nitrate solution and a glutathione solution or a tromethamine solution; (2) mixing the ultra-pure water, the sodium citrate solution, the chloroauric acid solution and the silver nitrate solution together to form a premixed solution, adding the glutathione solution or the tromethamine solution into the premixed solution to form a mixed solution; when the silver nitrate solution and the ultra-pure water are not used, solutions does not need to be mixed; (3) rapidly injecting the mixed solution into the boiling ultra-pure water which is used in a reaction, or directly injecting the solutions into the boiling ultra-pure water which is used in the reaction; and (4) carrying out heating reflux on the mixture, and naturally cooling extraction to room temperature. The synthetic method of the water-solubility biocompatibility monodisperse spherical gold nanometer crystals has the advantages of being simple in operation, good in repeatability, capable of obtaining the water-solubility biocompatibility monodisperse spherical gold nanometer crystals which are high in quality and can not be obtained in other existing methods.

The invention relates to a method for preparing gold crystals from nanometer to micrometer by adopting surface active agent molecule C18N3 as reducing agent and protecting agent. The surface active agent molecule C18N3 is not only adopted as the reducing agent to reduce chloroauric acid and obtain crystal nucleus, but also used as a sort of good protecting agent to facilitate the shape control and the growth of the metal crystals. Compared with the conventional method, the surface active agent molecule C18N3 is adopted in hydrothermal method applied in the invention to prepare the metal crystals, the prepared metal crystals have better shape controllability. By simply adjusting the molar ratio between the surface active agent molecule C18N3 and the chloroauric acid as well as the concentration of chloride in the solution, the metal crystals with different shapes can be prepared, including sphere, decahedron, plane triangle, plane pentagon and plane hexagon and two-dimension sheet shape.

The invention discloses icosidodecahedron gold nanocrystal and a controllable preparation method thereof; the icosidodecahedron is composed of 8 low-crystal-face hexagonal sides and 24 high-crystal-face pentagonal sides, and each hexagonal side is provided with 6 pentagonal sides around; the controllable preparation method comprises: subjecting gold chloride (HAuCl4) to direct synthesis by one-step reduction of high-temperature reflux reduction method, with the cationic surfactant diallyldimethylammonium chloride (PDDA) as a protectant and morphological guide agent, and ethylene glycol (EG)/pentanediol (PD) as a solvent and reducing agent. The agents used herein are simple, easy to obtain, and green, the preparation method is simple and efficient and is highly repeatable, the yield of the prepared icosidodecahedron gold nanocrystal is higher than 95%, and the prepared icosidodecahedron gold nanocrystal has regular and unique morphology, good monodispersity and uniformly distributed particle size. The icosidodecahedron gold nanocrystal and the preparation method thereof are of important application value to the mass synthesis of multifaceted gold nanocrystal, and of important guide significance to the controllable synthetic preparation of other polyhedral noble metal nanocrystals.

Surface enhanced Raman scattering (SERS) spectra of 4-mercaptobenzoic acid (4-MBA) self-assembled monolayers (SAMs) on gold substrates is presented for SAMs onto which gold nanoparticles of various shapes have been electrostatically immobilized. SERS spectra of 4-MBA SAMs are enhanced in the presence of immobilized gold nanocrystals by a factor of 10⁷-10⁹ relative to 4-MBA in solution. Large enhancement factors are a likely result of plasmon coupling between the nanoparticles (localized surface plasmon) and the smooth gold substrate (surface plasmon polariton), creating large localized electromagnetic fields at their interface, where 4-MBA molecules reside in this sandwich architecture. Moreover, enhancement factors depend on nanoparticle shape, and vary by a factor of 10².

The invention relates to a method for preparing an urchin-like gold nano-crystal with controllable lug spacing. The method comprises the following steps: firstly modifying double-stranded DNA (dsDNA)molecules to the surface of gold nano-spheres (AuNSs) to prepare an AuNSs/dsDNA compound; and performing an in-situ reduction reaction on chloroauric acid and a reducing agent in a solution to generate the urchin-like gold nano-crystal under the guiding effect of the AuNSs/dsDNA compound. The invention further relates to the urchin-like gold nano-crystal prepared by the preparation method, the spacing of lugs on the surface of the nano-crystal and the location of largest resonance absorption peak of plasma on the surface of the nano-crystal can be controlled by changing the composition of dsDNA. Compared with the prior art, the preparation method has the advantages of easy implementation and low synthesis cost, and can regulate and control the surface spacing and performance of the urchin-like gold nano-crystal.

A method for preparing concave cubic platinum-rare earth alloy nanocrystals based on a eutectic solvent is disclosed, and belongs to the technical field of fuel cell catalyst preparation. The eutecticsolvent which is novel, green and non-aqueous is adopted as a medium to prepare the concave cubic platinum-rare earth alloy nanocrystals with a surface of a {hk0} high-index crystal face structure byelectrochemical cyclic voltammetry without the need of any surfactant. The high-index crystal face has an open type surface structure so that a high number of active sites can be provided and catalyst performance can be significantly improved through a double-function mechanism of an alloyed surface electron structure, and therefore, the nanocrystals have excellent electrocatalytic performance for fuel molecules such as formic acid, methanol and ethanol, and have broad application prospects in the field of fuel cells, the field of electrosynthesis, and the like.

The invention discloses a series of lead-free full-inorganic silver-sodium mixed double perovskite alloy nanocrystal materials, which are prepared by the following steps: adding a cesium-containing compound, sodium acetate, silver acetate and indium acetate into a flask, adding 1-octadecene, oleic acid and oleylamine, stirring and mixing, and vacuumizing at 105 DEG C for 1 hour; introducing nitrogen, heating to 185 DEG C at a speed of 5 DEG C/min, injecting a chlorine-containing compound at 170 DEG C, quickly performing ice bath to room temperature when the temperature is 185 DEG C, centrifuging to remove the supernatant, washing twice with toluene, centrifuging to remove the supernatant, dispersing the precipitate into n-hexane, and centrifuging to remove the precipitate, thereby obtaining the nanocrystal colloid. According to the invention, the preparation method is simple, the toxicity problem of the lead-based perovskite is solved, the stability of the perovskite nanocrystal is improved, the fluorescence property of the perovskite nanocrystal is improved by regulating the ratio of sodium to silver, and the perovskite nanocrystal material has a good application prospect in the photoelectric field.

The invention discloses a surface plasmon switch manufactured by a gold polyaniline composite nanomaterial based on a core-shell structure and a manufacturing method thereof; polyaniline having adjustable dielectric properties is used for endowing gold nanocrystals with a controllable three-dimensional dielectric environment, the dielectric properties of the three-dimensional dielectric environment is reversibly controlled through introducing an electrochemical means and changing the proton doping level, so as to realize the construction of the surface plasmon resonance switch. After the dielectric properties of the polyaniline shell layer structure is adjusted by the electrochemical means, the surface plasmon switch can have the function of high pass of visible light wave bands and low permeability of near infrared wave bands, thereby having great application potential in design and manufacture of intelligent windows. The surface plasmon switch can also be placed in a micro flow chip, is used as an optical switch of the micro flow chip, and is advantageous for optical analysis of a sample in the chip. The surface plasmon switch is manufactured by a novel gold polyaniline composite nanomaterial with the core-shell structure, and the manufacturing method is provided.

The invention discloses a method for in-situ preparation of an Au/graphene nanocomposite through supercritical CO2. Gold-bearing precursors and graphite oxides are used as raw materials in the method, the gold-bearing precursors are dissolved into the supercritical CO2 and cosolvents, the supercritical CO2 is utilized to strip oxidized graphene, gold ions and oxidized graphene functional groups are subjected to mutual electrostatic attraction, gold cores generated from the reaction carry out intercalation on graphene, gold nanocrystals after deposition are firmly adsorbed to a graphene sheet layer, control over loads is realized by adjusting the reaction temperature and pressure, and the Au/graphene nanocomposite with uniformly-distributed gold nano particles having fine particle diameters is prepared. The preparation method is simple, efficient and environmentally friendly, and the prepared Au/graphene nanocomposite has the characteristics of good batch performance, small gold nano particle diameters, uniform distribution and a large load quantity and has wide and important application prospects in the fields such as lubrication, catalyzation and energy accumulation.

The invention discloses a low-temperature water-phase preparation method for porous gold nanocrystals, and belongs to the technical field of synthesis methods for porous nanostructures of precious metals. The low-temperature water-phase preparation method comprises the following steps: pouring sodium citrate solution, sodium carbonate solution and deionized water into a beaker, and placing the beaker in an ice-water mixed water bath environment at 0 DEG C and stirring for 1 hour; dripping chloroauric acid, and continuing to stir for 4 hours; then settling in the ice-water mixed water bath environment at 0 DEG C for 2-72 hours, and carrying out centrifuging and sample washing at a room temperature to obtain the gold nanocrystals. The porous gold nanocrystals prepared by the preparation method disclosed by the invention are of a porous structure, large in specific surface area, high in activity, high in permeability, capable of greatly improving the various physicochemical properties thereof, and adjustable in morphology. The method disclosed by the invention is green and environment-friendly, and simple and efficient.

The invention discloses a preparation method of a shape-controllable gold nanocrystal/poly(3, 4-ethylene dioxythiophene) core-shell nanomaterial. The preparation method includes following steps: (1),dissolving 3, 4-ethylene dioxythiophene monomer in a water solution of an anionic surfactant, adding a proper amount of isopropanol, and stirring at room temperature for 1-5h; (2), adding gold nanocrystals with specific shape and size, dispersing the same into a material obtain in the step (1), and mixing and oscillating for 10-30min; (3), dissolving an oxidant in protonic acid, mixing and oscillating with a material obtained in the step (2) for 3-10min, and allowing reaction at room temperature for 5-8h. High affinity between sulfur atoms in 3, 4-ethylene dioxythiophene molecules and the goldnanocrystals is utilized to enable 3, 4-ethylene dioxythiophene to be polymerized in situ on the surfaces of the gold nanocrystals so as to form an nm shell layer structure under stable action of theanionic surfactant.

The invention discloses a method for preparing gold nanocrystals with high density at room temperature, comprising the following steps of: firstly using an atomic layer to deposit to form an Al2O3 thin film or an HfO2 thin film on a substrate; soaking the Al2O3 thin film or the HfO2 thin film in aminopropyl trimethoxy silane aqueous solution with the mass concentration being of 3-8 percent for 1.5-3 hours; putting the Al2O3 thin film or the HfO2 thin film into aerosol, and soaking for 3-8 hours; and self-assembling the gold nanocrystals on the surface of the Al2O3 thin film or the HfO2 thin film. Furthermore, two metal electrodes which can be prepared into capacitance elements are formed by sputtering or electron beam evaporation on the surfaces of the backside and topside of the substrate respectively. The method has the advantages that the performance at room temperature avoids that the traditional high temperature treatment technology easily causes the gold nanocrystals formed more previously to suffer high temperature heat treatment for multiple times, thus ensuring the stable property of the gold nanocrystals which grow by self assembly; the obtained nanocrystal array has good uniformity; and the atomic layer deposition method realizes that Al2O3 and HfO2 can grow at the temperature lower than 350 DEG C, and the thickness of the thin film can be controlled precisely.

The invention belongs to the field of catalysts, and particularly relates to a platinum coated gold nanocrystal material and a preparation method and application thereof. The preparation method of the platinum coated gold nanocrystal material comprises the following step that firstly, gold nanocrystals, a piperazine derivative and a platinum source compound are mixed and reacted in a solvent to obtain the platinum coated gold nanocrystal material. According to the preparation method, the gold nanocrystal surface can be coated with a thin platinum layer, so that the prepared platinum coated gold nanocrystal material exhibits good catalytic performance. Besides, the preparation method is simple and quick, the treatment process is simple, no strong acid solvents or strong base solvents are utilized, and the preparation method has good application prospects. The experimental result shows that the thickness of the platinum layer of the prepared platinum coated gold nanocrystal material is the thickness of a sub-atom layer or a few of atomic layers.

The present invention relates to a simple method for showing gold nanocrystalline crystal structure and purity, belonging to the technical field of nanometer materials. The method comprises the stepsof: in a positive ion surface active agent solution system, taking gold nanocrystalline as seeds, and adding silver precursor and a reducing agent to prepare gold and silver nuclear shell nanocrystalline. Through deposition and growth of the sliver at the surface of the gold nanocrystalline, allow the shape of the gold nanocrystalline is clearer and simplify the analysis of the gold nanocrystalline crystal structure. The liquid interface self-assembly technology is employed to transfer the gold and silver nuclear shell nanocrystalline monolayer onto a silicon wafer to obtain scanning electronmicroscope representation samples. The assembling method can ensure uniform, single-layer and dense distribution of the nanocrystalline with different shapes on the silicon wafer to allow the statistics of the nanocrystalline to be more accurate and objective.