摘要:
A multimetallic nanoscale catalyst having a core portion enveloped by a shell portion and exhibiting high catalytic activity and improved catalytic durability. In various embodiments, the core/shell nanoparticles comprise a gold particle coated with a catalytically active platinum bimetallic material. The shape of the nanoparticles is substantially defined by the particle shape of the core portion. The nanoparticles may be dispersed on a high surface area substrate for use as a catalyst and is characterized by no significant loss in surface area and specific activity following extended potential cycling.
摘要:
A multimetallic nanoscale catalyst having a sore portion enveloped by a shell portion and exhibiting high catalytic activity and improved catalytic durability. In various embodiments, the core/shell nanoparticles comprise a gold particle coated with a catalytically active platinum bimetallic material. The shape of the nanoparticles is substantially defined by the particle shape of the core portion. The nanoparticles may be dispersed on a high surface area substrate for use as a catalyst and is characterized by no significant loss in surface area and specific activity following extended potential cycling.
摘要:
A multimetallic nanoscale catalyst having a core portion enveloped by a shell portion and exhibiting high catalytic activity and improved catalytic durability. In various embodiments, the core/shell nanoparticles comprise a gold particle coated with a catalytically active platinum bimetallic material. The shape of the nanoparticles is substantially defined by the particle shape of the core portion. The nanoparticles may be dispersed on a high surface area substrate for use as a catalyst and is characterized by no significant loss in surface area and specific activity following extended potential cycling.
摘要:
A multimetallic nanoscale catalyst having a sore portion enveloped by a shell portion and exhibiting high catalytic activity and improved catalytic durability. In various embodiments, the core/shell nanoparticles comprise a gold particle coated with a catalytically active platinum bimetallic material. The shape of the nanoparticles is substantially defined by the particle shape of the core portion. The nanoparticles may be dispersed on a high surface area substrate for use as a catalyst and is characterized by no significant loss in surface area and specific activity following extended potential cycling.
摘要:
A process of forming a hard-soft phase, exchange-coupled, magnetic nanocomposite includes forming a dispersion of magnetic nanoparticles, separating the magnetic nanoparticles from a solvent of the dispersion so as to allow self-assembly of the magnetic nanoparticles, and removing a coating from the nanoparticles, which are disposed in a self-assembled, locally-ordered nanostructure.
摘要:
A method and structure for making magnetite nanoparticle materials by mixing iron salt with alcohol, carboxylic acid and amine in an organic solvent and heating the mixture to 200–360 C is described. The size of the particles can be controlled either by changing the iron salt to acid/amine ratio or by coating small nanoparticles with more iron oxide. Magnetite nanoparticles in the size ranging from 2 nm to 20 nm with a narrow size distribution are obtained with the invention. The invention can be readily extended to other iron oxide based nanoparticle materials, including M Fe2O4 (M=Co, Ni, Cu, Zn, Cr, Ti, Ba, Mg) nanomaterials, and iron oxide coated nanoparticle materials. The invention also leads to the synthesis of iron sulfide based nanoparticle materials by replacing alcohol with thiol in the reaction mixture. The magnetite nanoparticles can be oxidized to γ-Fe2O3, or α-Fe2O3, or can be reduced to bcc-Fe nanoparticles, while iron oxide based materials can be used to make binary iron based metallic nanoparticles, such as CoFe, NiFe, and FeCoSmx nanoparticles.
摘要翻译:描述了通过将铁盐与醇,羧酸和胺在有机溶剂中混合并将混合物加热至200-360℃来制备磁铁矿纳米颗粒材料的方法和结构。 颗粒的大小可以通过将铁盐改变成酸/胺的比例或通过用更多的氧化铁涂覆小的纳米颗粒来控制。 通过本发明获得尺寸范围为2nm至20nm且具有窄尺寸分布的磁铁矿纳米颗粒。 本发明可以容易地扩展到其它基于氧化铁的纳米颗粒材料,包括M Fe 2 O 4(M = Co,Ni,Cu,Zn,Cr,Ti,Ba ,Mg)纳米材料和氧化铁涂覆的纳米颗粒材料。 本发明还导致通过在反应混合物中用硫醇代替醇来合成基于硫化铁的纳米颗粒材料。 磁铁矿纳米粒子可被氧化成γ-Fe 2 O 3 3或α-Fe 2 O 3 3, 或可以还原成bcc-Fe纳米颗粒,而基于氧化铁的材料可用于制备二元铁基金属纳米颗粒,例如CoFe,NiFe和FeCoSmx纳米颗粒。
摘要:
Magnetic materials and uses thereof are provided. In one aspect, a magnetic film is provided. The magnetic film comprises superparamagnetic particles on at least one surface thereof. The magnetic film may be patterned and may comprise a ferromagnetic material. The superparamagnetic particles may be coated with a non-magnetic polymer and/or embedded in a non-magnetic host material. The magnetic film may have increased damping and/or decreased coercivity.
摘要:
A method and structure that forms a multilayer nanoparticle thin film assembly begins by functionalizing a substrate with functional molecules. Next, the invention replaces a stabilizer on a bottom surface of the first nanoparticles with the functional molecules via surface ligand exchange to make a first nanoparticle layer on the substrate. The invention then replaces the stabilizer on a top surface of the first nanoparticle layer with functional molecules via surface ligand exchange. The invention replaces the stabilizer on a bottom surface of the second nanoparticles with the functional molecules via surface ligand exchange to make a second nanoparticle layer on the first nanoparticle layer. Lastly, the invention repeats the previous steps and forms additional nanoparticle layers.
摘要:
A method for making nanoparticles via metal salt reduction comprises, first, mixing metal salts in a solvent. Second, a reducing agent is added to the solvent at a temperature in the range of 100° C. to 350° C. Third, the nanoparticles dispersion is stabilized. Fourth, the nanoparticles are precipitated from the nanoparticle dispersion. Finally, the nanoparticles are re-dispersed into the solvent. The metal salt comprises a combination of FeCl2, FeCl3, Fe(OOCR)2, Fe(RCOCHCOR)3, CoCl2, Co(OOCR)2, Co(RCOCHCOR)2, and one of Pt(RCOCHCOR)2, PtCl2. The reducing agent comprises one of MBR3H, MH, M naphthalides, and polyalcohol; wherein R comprises one of H and an alkyl group, wherein M comprises one of Li, Na, and K. Long chain alkyl diols, and alkyl alcohol, can be used as a co-surfactant or a co-reducing agent to facilitate nanoparticle growth and separation.
摘要:
A method and structure for forming magnetic alloy nanoparticles includes forming a metal salt solution with a reducing agent and stabilizing ligands, introducing an organometallic compound into the metal salt solution to form a mixture, heating the mixture to a temperature between 260° and 300° C., and adding a flocculent to cause the magnetic alloy nanoparticles to precipitate out of the mixture without permanent agglomeration. The deposition of the alkane dispersion of FePt alloy particles, followed by the annealing results in the formation of a shiny FePt nanocrystalline thin film with coercivity ranging from 500 Oe to 6500 Oe.