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.

The present disclosure is directed to methods for producing a single-walled carbon nanotube in a chemical vapor deposition (CVD) reactor. The methods comprise contacting liquid catalyst droplets and a carbon source in the reactor, and forming a single walled carbon nanotube at the surface of the liquid catalyst droplets.

To provide a metal-based structure or nanoparticles whose homogeneity is not deteriorated and whose sticking formation is easy, and a production method thereof with a high safety. A metal-based structure comprises a hydrogen compound, cluster, or an aggregate thereof, represented by the general formula: M.sub.mH. The M is a metal-based atom. The m is an integer of 3 or more and 300 or less. H is a hydrogen atom.

A method for producing small metal alloy nanoparticles of a first metal and a second metal, comprising: mixing, at room temperature in air, a first aqueous solution of first and second metal nanoparticle precursor species in a first molar ratio of the first metal to the second metal; mixing a separate organic ligand into the first aqueous solution; adding a reducing agent to the first aqueous solution; and aging the first aqueous solution for a first period. The method may further comprise characterizing by photoluminescence or other property the metal alloy nanoparticles from the first aqueous solution and/or from a second aqueous solution of first and second metal nanoparticle precursor species in a second molar ratio of the first metal to the second metal.

The present invention is directed to a process for making silver nanostructures, comprising reacting at least one polyol and at least one silver compound that is capable of producing silver metal when reduced, in the presence of a source of chloride or bromide ions, at least one copolymer, and at least one acid scavenger. The present invention is also directed to silver nanostructures made by the processes described herein.

To provide a metal-based structure or nanoparticles whose homogeneity is not deteriorated and whose sticking formation is easy, and a production method thereof with a high safety. A metal-based structure comprises a hydrogen compound, cluster, or an aggregate thereof, represented by the general formula: M.sub.mH. The M is a metal-based atom. The m is an integer of 3 or more and 300 or less. H is a hydrogen atom.

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.

Methods for producing silver nanostructures with improved dimensional control, yield, purity, monodispersity, and scale of synthesis.

Provided are a metal nanowire production method capable of producing long and thin metal nanowires, and metal nanowires produced thereby. A metal nanowire production method comprising, a step for preparing a solution containing a metal salt, a polymer, at least one selected from a group consisting of halides, sulfides, carbonates, and sulfates, and an aliphatic alcohol, and a step for heating and reacting the solution at the temperature of 100 C. to 250 C. for 10 minutes or more while maintaining a practical shear stress applied to the solution at 10 mPa.Math.m or less, wherein, during the heating and reacting step, ultraviolet-visible absorption spectrum change of the solution is measured, and a reaction time is controlled on the basis of the ultraviolet-visible absorption spectrum information.

Provided is a method for producing fine nickel powder used as suitable seed crystals for producing nickel powder from a solution containing a nickel ammine sulfate complex. The method for producing nickel powder sequentially includes: a mixing step of adding, to a solution containing a nickel ammine sulfate complex, a dispersant containing a sulfonate and an insoluble solid which is insoluble in the solution to form a mixed slurry; a reduction and precipitation step of charging a reaction vessel with the mixed slurry and then blowing hydrogen gas into the mixed slurry in the reaction vessel to reduce nickel complex ions contained in the mixed slurry to form nickel precipitate on a surface of the insoluble solid; and a separation step of separating the nickel precipitate on the surface of the insoluble solid from the surface of the insoluble solid to form nickel powder.