The microemulsion method is employed to synthesize iron nanoparticles with an average size of D3 nm using trioctyl phosphine oxide (TOPO) as a stabilizing agent. The morphology, structure, and composition of the nanoparticles are studied by transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and UVÈVIS spectroscopy. The iron nanoparticles show a remarkable surface-enhanced Raman scattering (SERS) activity, and the scheme of iron nanoparticle-on-electrode is successfully used in the in situ SERS study of adsorbed molecules. Electrocatalysis over the iron nanoparticles is demonstrated in the highly efficient and selective reduction of in the presence of oxygen.

Walls that build themselves: Long‐range nanowalls assemble with uniform tetragonal Mn3O4 nanoparticles by a simple solution‐phase synthesis method under low temperature and surfactant‐free conditions (see image). The magnetization of the sample is investigated. A mechanism for formation of the wall‐like crystals is suggested. These high‐quality single‐crystalline Mn3O4 nanopatterns hold great potential for fundamental studies of their properties as well as for applications in nanodevices.

Using a one-step solution phase approach, the authors have synthesized uniform jingle bell-shaped cobalt mesopheres (550–750nm) and assembled the mesospheres into long magnetic chains (20–30μm). All of the cobalt spheres are hollow with ∼40nm thick shells but each contains an ∼200nm diameter solid ball. The nano- to mesoscale structures were realized via reaction of CoCl2∙6H2O and N2H4∙H2O in the presence of polyvinylpyrrolidone (PVP) in an ethylene glycol solution. Magnetic measurements show a coercivity of about 75Oe with a remnance of 9.6emu∕g at 300K. We propose a possible mechanism for the formation of the nanoto mesoscale structures.

Manganese oxides are important materials in many applications. We describe, for the first time, the facile one-pot synthesis of highly crystallined λ-MnO2 nanodisks assembled from nanoparticles through a novel wet chemical route. Morphology evolutions, magnetic properties, and phase transitions are also studied by transmission electron microscopy, scanning electron microscopy and thermal gravimetric analysis. A mechanism for the formation of the λ-MnO2 nanodisks as well as their inner structure is proposed based on controlled experiments. The key to the successful preparation of this novel MnO2 nanostructure has been a synergic control of a surfactant, polyvinylpyrrolidone, and a solvent, dimethyl sulfoxide, capable of stabilizing the microreactors and promoting the assembly of manganese nanoparticles.

Highly branched Pd 2D nanowire networks are prepared by a template- and surfactant-free method in an ethylene glycol (EG)-dimethyl sulfoxide (DMSO) mixture under mild conditions. Pd nanowire networks with lengths ranging from hundreds of nanometers to several micrometers and branches with uniform diameters of ∼8 nm are grown. The most likely formation mechanism is also proposed. The as-produced Pd nanowire networks exhibit high surface-enhanced Raman scattering activity for 4-mercaptopyridine probe molecules with 5.0 × 10(-8) M concentration.

The differences of charge transfer processes in different assemblies were observed by the optical method of SERS.

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We report the synthesis of Fe nanocrystals (approximately 9 nm) in an anhydrous media, formamide, using poly(N-vinyl-2-pyrrolidone) (PVP) as a protecting agent. The morphology, structure, and composition of the PVP-coated Fe nanocrystals are studied by transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and FT-Raman spectroscopy. The surface properties of the PVP-coated Fe nanocrystals are studied by electrochemistry and micro-surface-enhanced Raman scattering (mSERS) using pyridine as a probing molecule. The PVP-coated Fe nanocrystals, when immobilized on an electrode substrate, display very good electrocatalytic activities in the selective reduction of H2O2 in the presence of oxygen and in the oxidation of NO.