Abstract This article provides a comprehensive review of current research activities that concentrate on one‐dimensional (1D) nanostructures—wires, rods, belts, and tubes—whose lateral dimensions fall anywhere in the range 1 to 100 nm. We devote most attention 1D nanostructures have been synthesized relatively copious quantities using chemical methods. begin this with an overview synthetic strategies exploited achieve growth. then elaborate these approaches following four sections: i)...

Hollow nanocrystals can be synthesized through a mechanism analogous to the Kirkendall Effect, in which pores form because of difference diffusion rates between two components couple. Starting with cobalt nanocrystals, we show that their reaction solution oxygen and either sulfur or selenium leads formation hollow resulting oxide chalcogenides. This process provides general route synthesis nanostructures large number compounds. A simple extension yielded platinum-cobalt yolk-shell...

This article presents an overview of current research activities that center on monodispersed colloidal spheres whose diameter falls anywhere in the range 10 nm to 1 μm. It is organized into three parts: The first part briefly discusses several useful methods have been developed for producing with tightly controlled sizes and well-defined properties (both surface bulk). second surveys some techniques demonstrated organizing these two- three-dimensionally ordered lattices. third highlights a...

A solution-phase approach has been demonstrated for the large-scale synthesis of silver nanowires with diameters in range 30−40 nm, and lengths up to ∼50 μm. The first step this process involved formation Pt (or Ag) nanoparticles by reducing PtCl2 AgNO3) ethylene glycol (EG) heated ∼160 °C. These could serve as seeds heterogeneous nucleation growth (formed AgNO3 EG) because their close match crystal structure lattice constants. In presence poly(vinyl pyrrolidone) (PVP), be directed into a...

Cation exchange has been investigated in a wide range of nanocrystals varying composition, size, and shape. Complete fully reversible occurs, the rates reactions are much faster than bulk cation processes. A critical size identified below which shapes complex evolve toward equilibrium shape with lowest energy during reaction. Above anion sublattice remains intact basic initial retained throughout exchange. The size-dependent change can also be used to infer features microscopic mechanism.

This Review summarizes recent developments in the field of responsive photonic crystal structures, including principles for design and fabrication many strategies applications, example as optical switches or chemical biological sensors. A number methods are now available to realize majority which rely on self-assembly processes achieve ordering. Compared with microfabrication techniques, approaches have lower processing costs higher production efficiency, however, major efforts still needed...

This paper describes a sol−gel approach for the coating of superparamagnetic iron oxide nanoparticles with uniform shells amorphous silica. The process has been successfully applied to particles contained in commercial ferrofluid (e.g., EMG 304 Ferrofluidics) and those synthesized through wet chemical process. thickness silica could be conveniently controlled range 2−100 nm by changing concentration solution. Fluorescent dyes, example, 7-(dimethylamino)-4-methylcoumarin-3-isothiocyanate...

High-temperature hydrolysis of FeCl3 in the presence a surfactant gives monodisperse superparamagnetic colloidal nanocrystal clusters (CNCs) magnetite with tunable sizes (30–180 nm; see scheme). The combination superparamagnetism, high magnetization, and water dispersibility makes these CNCs ideal candidates for applications such as drug delivery bioseparation. Supporting information this article is available on WWW under http://www.wiley-vch.de/contents/jc_2002/2007/z700197_s.pdf or from...

This paper describes a strategy that combines physical templating and capillary forces to assemble monodispersed spherical colloids into uniform aggregates with well-controlled sizes, shapes, structures. When an aqueous dispersion of colloidal particles was allowed dewet from solid surface had been patterned appropriate relief structures, the were trapped by recessed regions assembled whose structures determined geometric confinement provided templates. We have demonstrated capability...

Mesoscale hollow spheres of ceramic materials can be prepared by templating an appropriate sol–gel precursor against a crystalline array monodisperse polystyrene beads, as demonstrated here. Spheres well-controlled, uniform size and homogeneous wall thickness result, seen from the Figure, which shows TEM cross-sectional view TiO2 spheres.

In this work we have carried out systematic studies and identified the critical role of hydrogen peroxide instead generally believed citrate in well-known chemical reduction route to silver nanoplates. This improved understanding allows us develop consistently reproducible processes for synthesis nanoplates with high efficiency yields. By harnessing oxidative power H(2)O(2), various sources including salts metallic can be directly converted assistance an appropriate capping ligand, thus...

The rapid reduction of Na2PdCl4 by ethylene glycol in the presence poly(vinyl pyrrolidone) (PVP) has recently been demonstrated as a convenient method generating Pd cubooctahedra and twinned nanoparticles. Here we describe new procedure where triangular or hexagonal nanoplates could be selectively synthesized manipulating kinetics polyol process. More specifically, rate was substantially reduced through introduction Fe(III) species O2/Cl- pair, two wet etchants for Pd(0). etching power pair...

Colloidal hollow nanocrystals with controlled interior and shell thickness represent a class of important nanostructured materials, because their promising applications for nanoreactors, drug delivery, catalysis. Since the first report in 2004 on synthesis CoS CoO by sulfidation oxidation Co nanocrystals, several different kinds have been prepared similar approach that involves nanoscale Kirkendall effect. In this review, we introduce application well-known classical phenomenon metallurgy...

We describe a "surface-protected etching" strategy that allows convenient conversion of sol-gel derived silica into porous structures. Poly(vinyl pyrrolidone) is used to protect the near surface layer, and NaOH selectively etch interior spheres. Etching initially yields structures eventually removes core leave behind hollow spheres with shells. This useful for constructing core-shell systems where active nanomaterials are embedded in shell enhanced stability against aggregation....

Abstract Although electrocatalysts based on transition metal phosphides (TMPs) with cationic/anionic doping have been widely studied for hydrogen evolution reaction (HER), the origin of performance enhancement still remains elusive mainly due to random dispersion dopants. Herein, we report a controllable partial phosphorization strategy generate CoP species within Co‐based metal‐organic framework (Co‐MOF). Density functional theory calculations and experimental results reveal that electron...

Tuning crystal: Superparamagnetic nanocrystal clusters can self-assemble into colloidal photonic crystals in solution, whose stop bands be magnetically tuned across the entire visible spectrum. Owing to high magnetization and highly charged polyacrylate-capped surface of each cluster, show a rapid, reversible, widely tunable optical response external magnetic fields.

Gold nanoparticles have been coated with amorphous silica to form spherical colloids a core−shell structure. The thickness of shells could be conveniently controlled in the range tens several hundred nanometers by changing concentration sol−gel precursor or coating time. These serve as building blocks fabricate photonic devices. In one demonstration, we showed that these particles assembled into long-range ordered lattices (or crystals) over large areas exhibited optical properties different...

Novel nanotechnologies have allowed great improvements in the syn-thesis of catalysts with well-controlled size, shape, and surface properties. Transition metal nanostructures specific sizes shapes, for instance, shown promise as high selectivities relative ease recycling. Researchers already demonstrated new selective catalysis solution-dispersed or supported-metal nanocatalysts, some cases applied to types reactions. Several challenges remain, however, particularly improving structural...