An extensive comparative study of the effects of microwave versus conventional heating on the nucleation and growth of near-monodisperse Rh, Pd, and Pt nanoparticles has revealed distinct and preferential effects of the microwave heating method. A one-pot synthetic method has been investigated, which combines nucleation and growth in a single reaction via precise control over the precursor addition rate. Using this method, microwave-assisted heating enables the convenient preparation of polymer-capped nanoparticles with improved monodispersity, morphological control, and higher crystallinity, compared with samples heated conventionally under otherwise identical conditions. Extensive studies of Rh nanoparticle formation reveal fundamental differences during the nucleation phase that is directly dependent on the heating method; microwave irradiation was found to provide more uniform seeds for the subsequent growth of larger nanostructures of desired size and surface structure. Nanoparticle growth kinetics are also markedly different under microwave heating. While conventional heating generally yields particles with mixed morphologies, microwave synthesis consistently provides a majority of tetrahedral particles at intermediate sizes (5-7 nm) or larger cubes (8+ nm) upon further growth. High-resolution transmission electron microscopy indicates that Rh seeds and larger nanoparticles obtained from microwave-assisted synthesis are more highly crystalline and faceted versus their conventionally prepared counterparts. Microwave-prepared Rh nanoparticles also show approximately twice the catalytic activity of similar-sized conventionally prepared particles, as demonstrated in the vapor-phase hydrogenation of cyclohexene. Ligand exchange reactions to replace polymer capping agents with molecular stabilizing agents are also easily facilitated under microwave heating, due to the excitation of polar organic moieties; the ligand exchange proceeds with excellent retention of nanoparticle size and structure.

PCM-10 is a porous phosphine coordination material based on Ca(II) and tris(p-carboxylated) triphenylphosphine. The material provides a unique 3-dimensional surface of P(III) Lewis base sites, which is ideal for post-synthetic functionalization. The addition of Au(I) yields an advanced material that can selectively adsorb 1-hexene over n-hexane at room temperature.

In this study, a high-temperature reduction method is developed to prepare iron silicide nanoparticles in solution phase. The synthesis applies a reaction of silicon tetrachloride with iron pentacarbonyl in the presence of 1,2-hexadecanediol to form iron silicide nanoparticles. Under iron-rich synthetic conditions, superparamagnetic Fe3Si nanoparticles form. The saturation magnetization of Fe3Si nanoparticles has been found to be 60 emu/g by superconducting quantum interference device (SQUID) magnetometry technique. The value is close to that of iron oxide (Fe3O4) nanoparticles but less than that of iron nanoparticles. When silicon-rich conditions are used, mainly β-FeSi2 nanoparticles form. The nanoparticle size, size distribution, and crystallinity are characterized by transmission electron microscopy (TEM), electron diffraction (ED), X-ray diffraction (XRD), and atomic force microscopy (AFM).

In this study, a synthetic method to produce water-soluble iron-gold (Fe-Au) alloy nanoparticles is described. The diameter of the alloy nanoparticles is 4.9 ( 1.0 and 3.8 ( 1.0 nm for two different precursors of iron, ferrous sulfate heptahydrate (Fe 2+ ) and iron pentacarbonyl (Fe 0 ). The X-ray powder diffraction of the alloyed nanoparticles shows an appreciable shift in 2θ peak positions relative to pure gold or iron. Using Vegard's law, we estimated the particle's iron content to be 14.8 ( 4.7 mol %. The lattice constant of the alloy nanoparticles is found to be 4.0449 ( 0.0375 Å. The high-resolution transmission electron microscopy images show the presence of icosahedral structures in agreement with the previous high temperature synthesis of the Fe-Au alloy nanoparticles. The optical absorption of the alloy nanoparticles is distinctive from pure gold nanoparticles and shows a relatively narrow absorption band in the range of 642-662 nm depending upon the amount of gold precursor used.

A meso-porous Co3O4has been found to retain its structure and cycle stably in a Li-ion or Na-ion battery.