Mikio Miyake

Bio: Mikio Miyake is an academic researcher from Japan Advanced Institute of Science and Technology. The author has contributed to research in topics: Catalysis & Nanoparticle. The author has an hindex of 32, co-authored 102 publications receiving 5117 citations. Previous affiliations of Mikio Miyake include International Institute of Minnesota.

Size Control of Palladium Nanoparticles and Their Crystal Structures

Abstract: The mean diameter of monodispersed Pd nanoparticles could be controlled from 17 to 30 A in a one-step reaction by changing the amount of protective polymer, poly(N-vinyl-2-pyrrolidone) (PVP) and the kind and/or the concentration of alcohol in the solvent. Although increasing the amount of protective polymer made the size of Pd nanoparticles smaller, the particle size appeared to have a lower limit determined by the kind of alcohol. On the other hand, monodispersed Pd nanoparticles of smaller diameter were obtained in the order methanol > ethanol > 1-propanol, indicating that a faster reduction rate of [PdCl4]2- ions is an important factor to produce the smaller particles. The particle diameter showed a minimum at around 40 vol % of alcohol in solvent. Once the monodispersed Pd nanoparticles were obtained, the larger particles with a narrow size distribution could be easily synthesized by using the stepwise growth reaction. The Pd nanoparticles obtained here had fcc structures like that of bulk Pd, althoug...

Size Control of Monodispersed Pt Nanoparticles and Their 2D Organization by Electrophoretic Deposition

Abstract: We describe a simple method to control the size of Pt nanoparticles with the use of an alcohol reduction. They then are assembled on the electrode by an electrophoretic deposition. The mean diameter of monodispersed Pt nanoparticles can be controlled from 19 to 33 A in one-step reaction by changing the kind and/or the concentration of alcohol in water and the amount of protective polymer, poly(N-vinyl-2-pyrrolidone) (PVP). The monodispersed Pt nanoparticles of smaller diameter are obtained in the order of methanol > ethanol > 1-propanol, indicating that a faster reduction rate of [PtCl6]2- ions is an important factor to produce the smaller particles. The particle diameter decreases linearly with concentration of alcohol in water. Furthermore, increasing the amount of PVP makes the size of Pt nanoparticles smaller, the size distribution remaining quite narrow. By the combination of the one-step reaction with the stepwise growth reaction, Pt nanoparticles of arbitrary diameter in the range 19−50 A can be ob...

Size Evolution of Alkanethiol-Protected Gold Nanoparticles by Heat Treatment in the Solid State

Abstract: A simple method is proposed to control the size of alkanethiol-protected Au nanoparticles by heat treatment in the solid state. The mean diameter of the Au nanoparticles prepared by Brust's two-phase method (∼1.5 nm) was evolved to 3.4−9.7 nm by heating to 150−250 °C in air. The uniform growth of nanoparticles was not observed when tetraoctylammonium bromide (TOAB), which was used as a phase-transfer agent during the preparation of Au nanoparticles, was removed before the particle growth process. The crystal structures of Au nanoparticles and alkanethiol ligand structures on Au nanoparticles were characterized before and after the heat treatment. The size-evolution mechanism was discussed on the basis of the thermodynamic model. The heat-treated Au nanoparticles easily formed self-assembled 2D superlattices with hexagonal packing, where the alkanethiol protective agents with an all-trans conformation were estimated to interpenetrate each other.

Polymer-Protected Ni/Pd Bimetallic Nano-Clusters: Preparation, Characterization and Catalysis for Hydrogenation of Nitrobenzene

Abstract: Well-dispersed and stable colloidal dispersions of polymer-protected Ni/Pd bimetallic nanoclusters have been obtained over an entire composition range by an improved polyol reduction method, in which nickel(II) sulfate and palladium(II) acetate were reduced at high temperature by ethylene glycol in the presence of poly(N-vinyl-2-pyrrolidone). Transmission electron microscopy indicates that these bimetallic nanocluster particles have definitely monodispersed size-distributions, with each particle containing both nickel and palladium atoms. The alloy structure has also been shown by X-ray diffraction and extended X-ray absorption fine-structure analysis. X-ray absorption near-edge spectroscopic and X-ray photoelectron spectroscopic data have confirmed that the nickel in the bimetallic nanoclusters is in the zero-valence state, as stabilized by the presence of Pd. Dispersions of these bimetallic nanoclusters were used as homogeneous catalysts for hydrogenation of nitrobenzene at 30 °C under an atmospheric pr...

Gold nanoparticles: assembly, supramolecular chemistry, quantum-size-related properties, and applications toward biology, catalysis, and nanotechnology.

Abstract: Although gold is the subject of one of the most ancient themes of investigation in science, its renaissance now leads to an exponentially increasing number of publications, especially in the context of emerging nanoscience and nanotechnology with nanoparticles and self-assembled monolayers (SAMs). We will limit the present review to gold nanoparticles (AuNPs), also called gold colloids. AuNPs are the most stable metal nanoparticles, and they present fascinating aspects such as their assembly of multiple types involving materials science, the behavior of the individual particles, size-related electronic, magnetic and optical properties (quantum size effect), and their applications to catalysis and biology. Their promises are in these fields as well as in the bottom-up approach of nanotechnology, and they will be key materials and building block in the 21st century. Whereas the extraction of gold started in the 5th millennium B.C. near Varna (Bulgaria) and reached 10 tons per year in Egypt around 1200-1300 B.C. when the marvelous statue of Touthankamon was constructed, it is probable that “soluble” gold appeared around the 5th or 4th century B.C. in Egypt and China. In antiquity, materials were used in an ecological sense for both aesthetic and curative purposes. Colloidal gold was used to make ruby glass 293 Chem. Rev. 2004, 104, 293−346

Chemistry and properties of nanocrystals of different shapes.

Abstract: The interest in nanoscale materials stems from the fact that new properties are acquired at this length scale and, equally important, that these properties * To whom correspondence should be addressed. Phone, 404-8940292; fax, 404-894-0294; e-mail, mostafa.el-sayed@ chemistry.gatech.edu. † Case Western Reserve UniversitysMillis 2258. ‡ Phone, 216-368-5918; fax, 216-368-3006; e-mail, burda@case.edu. § Georgia Institute of Technology. 1025 Chem. Rev. 2005, 105, 1025−1102

Magnetic Iron Oxide Nanoparticles: Synthesis, Stabilization, Vectorization, Physicochemical Characterizations, and Biological Applications

Abstract: 1. Introduction 20642. Synthesis of Magnetic Nanoparticles 20662.1. Classical Synthesis by Coprecipitation 20662.2. Reactions in Constrained Environments 20682.3. Hydrothermal and High-TemperatureReactions20692.4. Sol-Gel Reactions 20702.5. Polyol Methods 20712.6. Flow Injection Syntheses 20712.7. Electrochemical Methods 20712.8. Aerosol/Vapor Methods 20712.9. Sonolysis 20723. Stabilization of Magnetic Particles 20723.1. Monomeric Stabilizers 20723.1.1. Carboxylates 20733.1.2. Phosphates 20733.2. Inorganic Materials 20733.2.1. Silica 20733.2.2. Gold 20743.3. Polymer Stabilizers 20743.3.1. Dextran 20743.3.2. Polyethylene Glycol (PEG) 20753.3.3. Polyvinyl Alcohol (PVA) 20753.3.4. Alginate 20753.3.5. Chitosan 20753.3.6. Other Polymers 20753.4. Other Strategies for Stabilization 20764. Methods of Vectorization of the Particles 20765. Structural and Physicochemical Characterization 20785.1. Size, Polydispersity, Shape, and SurfaceCharacterization20795.2. Structure of Ferro- or FerrimagneticNanoparticles20805.2.1. Ferro- and Ferrimagnetic Nanoparticles 20805.3. Use of Nanoparticles as Contrast Agents forMRI20825.3.1. High Anisotropy Model 20845.3.2. Small Crystal and Low Anisotropy EnergyLimit20855.3.3. Practical Interests of Magnetic NuclearRelaxation for the Characterization ofSuperparamagnetic Colloid20855.3.4. Relaxation of Agglomerated Systems 20856. Applications 20866.1. MRI: Cellular Labeling, Molecular Imaging(Inflammation, Apoptose, etc.)20866.2.

Nanoalloys: From Theory to Applications of Alloy Clusters and Nanoparticles

Abstract: 5.1. Nanoalloys of Group 11 (Cu, Ag, Au) 865 5.1.1. Cu−Ag 866 5.1.2. Cu−Au 867 5.1.3. Ag−Au 870 5.1.4. Cu−Ag−Au 872 5.2. Nanoalloys of Group 10 (Ni, Pd, Pt) 872 5.2.1. Ni−Pd 872 * To whom correspondence should be addressed. Phone: +39010 3536214. Fax:+39010 311066. E-mail: ferrando@fisica.unige.it. † Universita di Genova. ‡ Argonne National Laboratory. § University of Birmingham. | As of October 1, 2007, Chemical Sciences and Engineering Division. Volume 108, Number 3