A concentrated dispersion of nanometric silver particles, and a method of producing the dispersion, the dispersion including a first solvent; a plurality of nanometric silver particles, in which a majority are single-crystal silver particles, the plurality of nanometric silver particles having an average secondary particle size (d.sub.50) within a range of 30 to 300 nanometers, the particles disposed within the solvent; and at least one dispersant; wherein a concentration of the silver particles within the dispersion is within a range of 30% to 75%, by weight, and wherein a concentration of the dispersant is within a range of 0.2% to 30% of the concentration of the silver particles, by weight.

A novel method for manufacturing tabular silver nanoparticles with high productivity and high reproducibility. The present invention provides a method for manufacturing silver nanoparticles including a first step of preparing a silver ion aqueous solution containing a crystal habit modifier as a starting solution, a second step of adding a reducing agent to the starting solution with stirring to yield an aqueous dispersion of fine silver crystals, and a third step of adding an oxidizing agent to the aqueous dispersion with stirring. The oxidizing agent is preferably added such that the solubility of metal silver in the aqueous dispersion is optimized at an appropriate time in the third step.

The present disclosure relates to methods for producing nanoparticles. The nanoparticles may be made using ethanol as the solvent and the reductant to fabricate noble-metal nanoparticles with a narrow particle size distributions, and to coat a thin metal shell on other metal cores. With or without carbon supports, particle size is controlled by fine-tuning the reduction power of ethanol, by adjusting the temperature, and by adding an alkaline solution during syntheses. The thickness of the added or coated metal shell can be varied easily from sub-monolayer to multiple layers in a seed-mediated growth process. The entire synthesis of designed core-shell catalysts can be completed using metal salts as the precursors with more than 98% yield; and, substantially no cleaning processes are necessary apart from simple rinsing. Accordingly, this method is considered to be a green chemistry method.

A process for the synthesis of nanostructured metallic hollow spherical particles, in which the metal is deposited onto sacrificial masks formed in a polymeric colloidal solution by the electroless autocatalytic deposition method. Deposition releases only gaseous products (N.sub.2 and H.sub.2) during the oxidation thereof, which evolve without leaving contaminants in the deposit. The particulate material includes nanostructured metallic hollow spherical particles with average diameter ranging from 100 nm to 5 m and low density with respect to the massic metal. A process for compacting and sintering a green test specimen are also described.

A method for producing nanoparticles on a substrate using a metal precursor in an ionic liquid and microwave heating is described. The composite compositions are useful as catalysts for chemical reactions, fuel cell, supercapacitor and battery components, and the like.

A method for producing nanoparticles on a substrate using a metal precursor in an ionic liquid and microwave heating is described. The composite compositions are useful as catalysts for chemical reactions, fuel cell, supercapacitor and battery components, and the like.

Objects of the invention are to provide a method in which coated metal fine particles are smoothly manufactured when the coated metal fine particles are manufactured using a metal amine complex decomposition method, and, particularly, to provide coated metal fine particles that can be smoothly sintered even at a low temperature. The manufacturing method of coated metal fine particles includes a first step of mixing an amine liquid mixture of an alylamine having 6 or more carbon atoms and an alkylamine having 5 or less carbon atoms with a metal compound including one or more metal atoms, thereby generating a complex compound including the metal compound and amines; and a second step of heating and decomposing the complex compound, thereby generating coated metal fine particles.

Provided is a method for producing nickel powder from a nickel ammine sulfate complex solution, comprising treatment steps of: (1) a seed crystal production step of producing nickel powder having an average particle size of 0.1 to 5 m; (2) a seed crystal addition step of adding the nickel powder obtained in the step (1) as seed crystals to form a mixed slurry; (3) a reduction step of forming a reduced slurry containing nickel powder formed by precipitation of a nickel component in the mixed slurry on the seed crystals; and (4) a growth step of performing solid-liquid separation to separate and recover the nickel powder as a solid phase component and then blowing hydrogen gas into a solution prepared by adding the nickel ammine sulfate complex solution to the recovered nickel powder to grow the nickel powder to form high purity nickel powder.

Provided are a method for producing nickel seed crystals that maintains and improves the quality of nickel powder at a low cost while suppressing production cost and environmental load in the production of nickel powder, by optimizing the amount of hydrazine added when producing fine nickel powder as seed crystals using hydrazine; and a method for producing nickel powder using the nickel seed crystals. The method for producing seed crystals used for producing hydrogen-reduced nickel powder, including adding, to an acid solution containing nickel ions that is maintained at a temperature of 50 to 60 C., hydrazine of 1 to 1.25 mol per 1 mol of a nickel component contained in the acid solution to produce the seed crystals.

Provided is a block copolymer that makes it possible to produce inorganic nanoparticles that can be dispersed in an organic solvent, the inorganic nanoparticles being of uniform size and a reducing agent not having to be used.

A block copolymer including a catechol segment represented by formula (1).

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