A variety of polyhedral nanocages are provided having a hollow interior, ultrathin walls, and well-defined facets of metal atoms. The nanocages can include a variety of precious metals such as Pt, Au, Ru, Rh, or Ir. The metal atoms can take a face-centered cubic structure with {111} facets on the surface. The walls can be thin, sometimes less than 1 nm in thickness or only a few atomic layers in thickness. The nanocages can provide for efficient uses of valuable precious metals, among other things, in catalysis. For example, catalysts are provided exhibiting high mass activities in oxygen reduction reactions. Methods of making and methods of using the nanocages and catalysts are also provided.

This silver paste includes a silver powder and a solvent, in which the silver powder includes first silver particles having a particle size of 100 nm or more and less than 500 nm, second silver particles having a particle size of 50 nm or more and less than 100 nm, and third silver particles having a particle size of 1000 nm or more and less than 10000 nm, and the content of the first silver particles is 12% by volume or more and 90% by volume or less, the content of the second silver particles is 1% by volume or more and 38% by volume or less, and the content of the third silver particles is 5% by volume or more and 80% by volume or less, regarding a total amount of the silver powder as 100% by volume.

A soft magnetic alloy powder includes soft magnetic alloy particles having an amorphous phase. Each of the soft magnetic alloy particles has chemical composition represented by Fe.sub.aSi.sub.bB.sub.cC.sub.dP.sub.eCu.sub.fSn.sub.gM1.sub.hM2.sub.i, where M1 is one or more elements of Co and Ni, M2 is one or more elements of Ti, Zr, Hf, Nb, Ta, Mo, W, Cr, Al, Mn, Ag, V, Zn, As, Sb, Bi, Y, and a rare earth element, and 79≤a+h+i≤86, 0≤b≤5, 7.2≤c≤12.2, 0.1≤d≤3, 7.3≤c+d≤13.2, 0.5≤e≤10, 0.4≤f≤2, 0.3≤g≤6, 0≤h≤30, 0≤i≤5, and a+b+c+d+e+f+g+h+i=100 (parts by mol) are satisfied.

A method for producing fine copper particles includes producing fine copper particles having a coating film containing cuprous oxide on a surface by heating copper or a copper compound in a reducing flame formed by a burner. The fine copper particles are produced by adjusting a mixing ratio between a combustible gas and a combustion supporting gas which form the reducing flame such that a volume ratio of CO/CO.sub.2 is in a range of 1.5 to 2.4.

The present disclosure relates to a stable copper-based core-shell nanoparticle and its process of manufacture. Further, the present disclosure relates to the use of the copper-based core-shell nanoparticles as plasmonic photocatalysts in photocalysis and hydrogen production.

A caster assembly configured to process and store a material includes a reaction chamber, a storage assembly configured to store material processed in the reaction chamber, and a blower configured to process and store the material. The reaction chamber includes a vessel configured to hold the material in a melted state prior to processing and a powder generating assembly configured to receive the material from the melting vessel. The powder generating assembly includes a feeding chamber and a feeding device disposed at least partially within the feeding chamber. The feeding device includes at least one nozzle configured to inject inert fluid, where the fluid is a gas, liquid, or combination of the two into the feeding chamber and a material inlet through which the material is configured to flow into the feeding chamber to be exposed to the inert fluid, where the fluid is a gas, liquid, or combination of the two.

Provided are: a production method for silver fine particles that retain capabilities such as conductivity and make it possible to form wiring at even lower temperatures; and silver fine particles. A silver fine particle production method in which silver powder is used to produce silver fine particles by means of a gas phase method. The silver fine particle production method has a step for supplying an organic acid to the silver fine particles. The gas phase method is, for example, a plasma method or a flame method. The silver fine particles have a surface coating that includes at least a carboxyl group.

Fine particles that can be sintered and grow to 100 nm or larger without oxidation even when retained at a baking temperature in an oxygen-containing atmosphere and that can suppress oxidation in a long-term preservation in the air or other oxygen-containing atmospheres, a method of producing the fine particles, and a method of producing fine particles that can suppress oxidation in a collecting process after the production of the fine particles. A fine particle production method for producing fine particles using feedstock powder by means of a gas-phase process includes a step of producing fine particle bodies by converting the feedstock powder into a mixture in a gas phase state using a gas-phase process and cooling the mixture in a gas phase state with a quenching gas containing an inert gas and a hydrocarbon gas having 4 or less carbon atoms, and a step of supplying an organic acid to the produced fine particle bodies.

This invention relates to the nano metal material preparation technology field, especially to the preparation method of one kind, of nano-rings. This invention uses polyvinyl pyrrolidone of different molecular weights as surface-protecting agent and dissolves silver nitrate in the low molecular weight polyvinyl pyrrolidone ethylene glycol solvent under frozen conditions. Frozen conditions can slow down or inhibit silver ions from being reduced to zero-valent silver, to generate silver nanoparticles coated and complexed with both low and high molecular weight polyvinyl pyrrolidone. Polyvinyl pyrrolidone of different molecular weight shows different selective absorption of silver, and different stability makes it affect the speed of growth of silver atoms along different crystal faces to different extent, which is better for silver nano-ring production, with higher yield. Silver nano-rings made from this invention features perfect circular shape, smooth surface, oval cross-section, and great crystal structure, and can be used as transparent flexible conductive material.

A production method for a refined product of a metal nanoparticle-containing composition, including causing a metal nanoparticle-containing composition to pass in a liquid state from one side to the other side of a porous polyimide and/or polyamide-imide membrane having interconnection pores with differential pressure, and a production method for a refined product of a metal nanoparticle dispersion liquid, including causing a metal nanoparticle dispersion liquid to pass from one side to the other side of a porous polyimide and/or polyamide-imide membrane having interconnection pores with differential pressure.