Proposed are a method of preparing a metal nanostructure, which includes (a) preparing a first metal template whose surface is coated with a polymeric micelle containing an amphiphilic polymer and (b) causing the first metal template to react with a second metal ion through a galvanic replacement reaction, and a metal nanostructure prepared thereby. The amphiphilic polymer is used as a capping agent during the replacement reaction so that the micellar polymer is adsorbed onto the template, thereby selectively allowing the replacement reaction. Thus, unlike in existing technologies in which nanostructures having limited forms are prepared, nanostructures having a new two-dimensional structure, including nanostructures having a plurality of pores formed between nanoparticles, can be prepared. Additionally, a mixing ratio of two types of solvents that differ in polarity index is adjustable to control the size of the polymeric micelle, thereby changing the structural characteristics of a finally prepared metal nanostructure.

An approach to synthesizing and assembling nanoparticles into discrete, size-tunable, pre-designed architectures is realized in a single synthetic/process step.

A castable, moldable, or extrudable magnesium-based alloy that includes one or more insoluble additives. The insoluble additives can be used to enhance the mechanical properties of the structure, such as ductility and/or tensile strength. The final structure can be enhanced by heat treatment, as well as deformation processing such as extrusion, forging, or rolling, to further improve the strength of the final structure as compared to the non-enhanced structure. The magnesium-based composite has improved thermal and mechanical properties by the modification of grain boundary properties through the addition of insoluble nanoparticles to the magnesium alloys. The magnesium-based composite can have a thermal conductivity that is greater than 180 W/m-K, and/or ductility exceeding 15-20% elongation to failure.

A castable, moldable, or extrudable magnesium-based alloy that includes one or more insoluble additives. The insoluble additives can be used to enhance the mechanical properties of the structure, such as ductility and/or tensile strength. The final structure can be enhanced by heat treatment, as well as deformation processing such as extrusion, forging, or rolling, to further improve the strength of the final structure as compared to the non-enhanced structure. The magnesium-based composite has improved thermal and mechanical properties by the modification of grain boundary properties through the addition of insoluble nanoparticles to the magnesium alloys. The magnesium-based composite can have a thermal conductivity that is greater than 180 W/m-K, and/or ductility exceeding 15-20% elongation to failure.

Provided is a preparation method of copper nanostructures, characterized in that a copper precursor including halide is reacted with polyethyleneimine (PEI) and a reducing agent in an aqueous solution. According to this method, the copper nanostructures may be easily prepared in a sphere, wire, or plate form, and high-quality copper nanostructures may be produced with a high production yield of 90% or more. This method is also appropriate for large-scale production.

Copper particles are provided mainly containing a copper element. In the copper particles, a ratio (S1/B) of a first crystallite size S1 to a particle size B is 0.23 or less, where the first crystallite size is obtained using Scherrer equation from a full width at half maximum of a peak derived from (111) plane of copper in X-ray diffraction measurement, and the particle size is calculated from a BET specific surface area. In the copper particles, a ratio (S1/S2) of the first crystallite size S1 to a second crystallite size S2 is 1.35 or less, where the second crystallite size is obtained using Scherrer equation from a full width at half maximum of a peak derived from (220) plane of copper in X-ray diffraction measurement. A method for manufacturing the copper particles is also provided.

The present disclosure relates to a preparation method and use of a thickness-controllable bismuth nanosheet and its alloy, in order to solve the technical problems that the existing metal catalysts for the conversion of carbon dioxide to formic acid exhibit a low efficiency, a high overpotential, a relatively positive hydrogen evolution potential, and a poor stability. The present disclosure for the first time obtains a bismuth nanosheet of a single atom layer thickness with a thickness of only 0.7 nm through an aqueous solution reduction method by using a bismuth salt compound as a raw material, using ethylene glycol ethyl ether as a solvent, and using a highly reductive aqueous solution containing NaBH.sub.4, LiBH.sub.4 or the like as a reducing agent, under a protection atmosphere of an inert gas; and the thickness is adjustable. The bismuth nanosheet prepared according to the present disclosure exhibits an excellent CO.sub.2 catalytic reduction property. In the case of a 330 mV overpotential, the Faradic efficiency of catalyzing CO.sub.2 to produce formic acid can reach 98%, the initial overpotential is as low as 80 mV, and the stability lasts for as long as 75 h. Moreover, even if treated at a temperature of 300 C. for 4 h, the thickness and catalytic property of the bismuth nanosheet are almost unchanged, further demonstrating its ultrahigh stability.

Provided is a plurality of flaky magnetic metal particles of embodiments, each flaky magnetic metal particle having a flat surface having either or both of a plurality of concavities and a plurality of convexities, the concavities or convexities being arranged in a first direction and each having a width of 0.1 m or more, a length of 1 m or more, and an aspect ratio of 2 or higher; and a magnetic metal phase containing at least one primary element selected from the group consisting of iron (Fe), cobalt (Co), and nickel (Ni). The flaky magnetic metal particles have an average thickness of between 10 nm and 100 m inclusive, and the average value of the ratio of the average length within the flat surface with respect to the thickness is between 5 and 10,000 inclusive.

Provided is copper paste for joining including metal particles, and a dispersion medium. The metal particles include sub-micro copper particles having a volume-average particle size of 0.12 m to 0.8 m, and micro copper particles having a volume-average particle size of 2 m to 50 m, a sum of the amount of the sub-micro copper particles contained and the amount of the micro copper particles contained is 80% by mass or greater on the basis of a total mass of the metal particles, and the amount of the sub-micro copper particles contained is 30% by mass to 90% by mass on the basis of a sum of a mass of the sub-micro copper particles and a mass of the micro copper particles.

According to embodiments of the present invention, an ink composition is provided. The ink composition includes a plurality of nanostructures distributed in at least two cross-sectional dimension ranges, wherein each nanostructure of the plurality of nanostructures is free of a cross-sectional dimension of more than 200 nm. According to further embodiments of the present invention, a method for forming a conductive member and a conductive device are also provided.