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In this study, metal-containing nanoparticles (NPs) were produced using electrical explosion of wires (EEW) in organic solvents. The explosion chamber was constructed from Teflon to withstand the shockwave, allow growth and reaction of the incipient NPs in various organic solvents containing dissolved ligands, and allow a constant flow of argon to maintain an inert environment. A survey of different transition d-block metals was conducted with metals from groups 4-8, affording metal carbide NPs, while metals from groups 9-12 gave elemental metallic NPs. Tungsten carbide phase WC1-x, which has not been previously isolated as a single-phase material, was exclusively formed during EEW. We used polymerization initiation by electron-rich metallic nanoparticles (PIERMEN) as a capping technique for the nascent NPs with an alkyl epoxide employed as the monomers. Transmission electron microscopy showed spherical particles with the metallic core embedded in a polymer matrix with predominantly smaller particles (<50 nm), but also a broad size distribution with some larger particles (>100 nm). Powder X-ray diffraction (PXRD) was used to confirm the identity of the metallic NPs. The capping agents were characterized using ATR-FTIR spectroscopy. No evidence is observed for the formation of crystalline oxides during EEW for any metals used. Differential scanning calorimetry/thermal gravimetric analysis was used to study the NP's behavior upon heating under an air flow up to 800 °C with the product oxides characterized by PXRD. The bifurcation between metal-carbide NPs and metal NPs correlates with the enthalpy of formation of the product carbides. We observed PIERMEN capping of elemental metal NPs only when the metal has negative standard electrode potentials (relative to a bis(biphenyl) chromium(I)/(0) reference electrode).

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We report here on the synthesis of nanoparticles (NPs) of sodium halide (NaX; X = F, Cl, Br, I) salts using reverse micelles (water/dioctylsodiumsulfosuccinate/toluene) with the resulting NPs having diameters of 1.5 to 2.5 nm. The initial core of reverse micelle contains a water-soluble salt. After evaporation of the volatile compounds under vacuum (water and toluene), NaX NPs are produced with an AOT surfactant cap. The NaX NPs redisperse in toluene. In contrast to previous syntheses of soluble salt NPs, Na + ions from the surfactant are found to completely exchange with the salt in the initial core of the reverse micelles. The resulting NPs were analyzed with dynamic light scattering (DLS), transmission electron microscopy (TEM), and selected area electron diffraction (SAED) which confirmed the exchange mechanism. Experimental results are compared and found to be in agreement with the recently published model by Bandopadhyaya and coworkers.