A metal microparticle coated with metal hydride nanoparticles is disclosed. Some variations provide a material comprising a plurality of microparticles (1 micron to 1 millimeter) containing a metal or metal alloy and coated with a plurality of nanoparticles (less than 1 micron) containing a metal hydride or metal alloy hydride. The invention eliminates non-uniform distribution of sintering aids by attaching them directly to the surface of the microparticles. No method is previously known to exist which can assemble nanoparticle metal hydrides onto the surface of a metal microparticle. Some variations provide a solid article comprising a material with a metal or metal alloy microparticles coated with metal hydride or metal alloy hydride nanoparticles, wherein the nanoparticles form continuous or periodic inclusions at or near grain boundaries within the microparticles.

Methods for preparing solid metal oxide nanoparticles via controlled oxidation comprising preparing a plurality of metal nanoparticles, contacting the plurality of metal nanoparticles with an aqueous agent to provide metal oxide nanoparticles having a desired particle size, and removing the resulting metal oxide nanoparticles from the aqueous agent. Aspects of the present disclosure also relate to solid metal oxide nanoparticles obtained by this method.

Described herein are metallic excavated nanoframes and methods for producing metallic excavated nanoframes. A method may include providing a solution including a plurality of excavated nanoparticles dispersed in a solvent, and exposing the solution to chemical corrosion to convert the plurality of excavated nanoparticles into a plurality of excavated nanoframes.

A general and well-controlled method for synthesizing intermetallic nanoparticles is provided. The method comprises: preparing noble-metal nanoparticle seeds; dispersing a metal precursor into the noble-metal nanoparticle seeds to form a first solution; adding the first solution into an organic solvent to form a first mixture; sonicating the first mixture at room temperature; subjecting the first mixture to a heat treatment under N.sub.2 atmosphere to render a second solution; cooling the second solution naturally to room temperature; adding ethanol to the second solution to form a third solution; and collecting the intermetallic nanoparticle from the third solution by centrifugation. The as-synthesized hollow orthorhombic Pd.sub.2Sn alloy nanoparticles can accelerate the cleavage of CC bond when compared with commercial Pd/C and display superior catalytic performance towards glycerol oxidation reaction and potential for promising applications.

A metal particle, in which holes are distributed at the center, has a high degree of sphericity, a low shrinkage ratio, and small grains therein. In a preparation method for the metal particle, spherical or quasi-spherical metal seed crystals are introduced to prepare a polyol-seed crystal system, so that the metal particle has a controllable particle size and degree of sphericity in a whole reduction process, metal particles in a metal oxide or metal salt solution containing a metal source in the seed crystals can be rapidly and stably reduced, and the shape of formed metal particles is guaranteed to spherical or quasi-spherical; and the particle sizes of the metal particles can be adjusted by means of the number and the sizes of the introduced spherical nano-metal seed crystals. The metal particles are applied to a photovoltaic cell or a semiconductor conducive adhesive.

A method for making metal nanorods comprises combining a source of metal cations with at least one surfactant to form a mixture, wherein the metal cations are reduced and the metal nanorods are produced. Metal nanorods produced by the method and uses thereof. The metal nanorods are useful in devices such as lateral flow devices.

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.

Multifunctional core@shell nanoparticles (CSNs) useful in electrochemical cells, particularly for use as an electrocatalyst material. The multifunctional CSNs comprise a catalytic core component encompassed by one or more outer shells. Also included are electrochemical cell electrodes and electrochemical cells that electrochemically convert carbon dioxide to, for example, useful fuels (e.g., synthetic fuels) or other products, and which comprise multifunctional CSNs, and methods for making the same.

A method for making metal nanorods comprises combining a source of metal cations with at least one surfactant to form a mixture, wherein the metal cations are reduced and the metal nanorods are produced. Metal nanorods produced by the method and uses thereof. The metal nanorods are useful in devices such as lateral flow devices.

A metal microparticle coated with metal hydride nanoparticles is disclosed. Some variations provide a material comprising a plurality of microparticles (1 micron to 1 millimeter) containing a metal or metal alloy and coated with a plurality of nanoparticles (less than 1 micron) containing a metal hydride or metal alloy hydride. The invention eliminates non-uniform distribution of sintering aids by attaching them directly to the surface of the microparticles. No method is previously known to exist which can assemble nanoparticle metal hydrides onto the surface of a metal microparticle. Some variations provide a solid article comprising a material with a metal or metal alloy microparticles coated with metal hydride or metal alloy hydride nanoparticles, wherein the nanoparticles form continuous or periodic inclusions at or near grain boundaries within the microparticles.