A hydroxyl ion assisted alcohol reduction method has been applied for the preparation of copper nanoparticles with an average diameter of 10.5 nm and narrow size distribution. The addition of specific amounts of hydroxyl ions to the alcoholic solution is the key to enhance the reducing potential of alcohols to obtain metal copper from their salts even with 1-butanol. The synthesis of copper metal was realized through intermediate steps corresponding to the formation of copper oxides (CuO and Cu 2 O). The obtained nanoparticles were coated with necessary surfactants and dispersed in organic solvent such as dodecane to prepare conducting ink. Samples annealed at 250 C in nitrogen and vacuum atmosphere showed electrical resistivity of 26 and 35 mU cm, respectively.

The monoanionic state of ethylene glycol was theoretically and experimentally confirmed to be the active species during reduction reaction of metal salts.

Ideal interaction-free magnetite nanoparticles were prepared, and their magnetic properties were measured to clarify the true nature of magnetic anisotropy of individual magnetite nanoparticles at the nanoscale and to analyze the shape, surface, and crystalline anisotropy contributions. Spherical (17.7 nm), cubic (10.6 nm), and octahedral-shaped magnetite nanoparticles with average sizes ranging from 7.6 to 23.4 nm were synthesized using solution techniques. Then, these nanoparticles were coated with silica at appropriate shell thicknesses to prepare magnetic interaction-free samples, and their noninteractive nature was confirmed through first-order reversal curve diagrams. For these well-isolated nanoparticles, remanent magnetizations of the hysteresis loops are just equal to a half of the saturation magnetization. This result clearly indicates that uniaxial magnetic anisotropy is predominant in each nanoparticle. In order to clarify the details of the uniaxial magnetic anisotropy, the analysis of blocking temperature−switching field distribution diagrams is constructed based on thermal decay curves of isothermal remanent magnetization at various applied fields. The obtained effective magnetic anisotropy constant K eff is distributed around 10−20 kJ/m 3 and has insignificant size dependence. This result seems inconsistent with the inverse proportion relation of K eff with size predicted for surface magnetic anisotropy. The theoretical calculation suggested that the crystalline magnetic anisotropy plays a major role in magnetic properties of the magnetite nanoparticles at lower temperatures. However, it should be noted that K eff seems slightly different for the different shapes. The above study indicates that control size, shape, and interparticle interactions is required to strictly discuss such delicate differences of magnetic anisotropy of individual magnetite nanoparticles for the design of thermal seeds for magnetic hyperthermia.

A modified alcohol reduction process by controlling the complexation and reduction of metallic ions was developed to obtain compositionally and structurally controlled Ni-Pt nanoparticles (NPs) with sizes less than 20 nm in a high yield. The characterization of NPs synthesized under different experimental conditions suggested that the reduction of Pt and subsequent formation of cubic-shaped Ni-Pt NPs were strongly dependent on the formation of Pt-oleylamine (OAm) complexes. Thus, prior to the synthesis of Ni-Pt NPs, the formation and reduction process of Pt complexes in the solution-state were investigated by in situ UV-Visible and X-ray spectroscopies. The complexation of Pt ions along with their reduction prior to the formation of Pt metal and their influence on the size and the elemental distribution of Pt within the Ni-Pt NPs were revealed. Then, the above findings were actively utilized to design and to obtain Pt(core)-Ni(shell), Ni-Pt alloy, and Ni(core)-Pt(shell) nanostructures by regulating the OAm concentration in the system. The specific distribution of Pt on the Ni-Pt surface was confirmed by decolorization of methylene blue. Furthermore, Ni-Pt NPs with a Pt concentration of 10 at.% exhibited a mass activity four times larger than that of commercial Pt during the oxygen reduction reaction (ORR).

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