Copper nanowires (NWs) with uniform diameters and lengths ranging from several hundreds of nanometers to several micrometers have been prepared with high yield by a simple hydrothermal procedure. The X-ray diffraction (XRD) and energy dispersive X-ray spectroscopy (EDS) analysis data indicate that the copper nanowires are free of any contamination, while the electron diffraction (ED) analysis has revealed the nanowires to be single crystals. The nanowire growth mechanism has also been discussed. Hexadecylamine is the surface stabilizing agent in our method, while glucose facilitates formation of single-crystalline seeds on which the copper nanowires grow. The electrical properties of the as-synthesized copper NWs have also been investigated.

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We demonstrate a simple method for the synthesis of nanoporous metal (Au, Pt, and Pd) rods by the galvanic exchange reaction using Ni as a sacrificial template. Nickel nanorods, prepared by electrodeposition inside porous alumina membrane, were converted to various nanoporous metallic structures by dispersing them in metal salt solutions of the respective metals that are galvanically exchanged. The catalytic activity of the porous Pt and Pd nanorods in the hydrogenation of ethylene was comparable to supported Pt and Pd nanoparticles. The porous nanorods provide a new form of unsupported catalysts in contrast to traditional supported nanoparticle catalysts and can be synthesized in uniform sizes and separated easily from the reaction mixtures without aggregation.

Owing to their higher intrinsic electrical conductivity and chemical stability with respect to their oxide counterparts, nanostructured metal sulfides are expected to revive materials for resistive chemical sensor applications. Herein, we explore the gas sensing behavior of WS 2 nanowire-nanoflake hybrid materials and demonstrate their excellent sensitivity (0.043 ppm-1) as well as high selectivity towards H 2 S relative to CO, NH 3 , H 2 , and NO (with corresponding sensitivities of 0.002, 0.0074, 0.0002, and 0.0046 ppm-1 , respectively). Gas response measurements, complemented with the results of X-ray photoelectron spectroscopy analysis and first-principles calculations based on density functional theory, suggest that the intrinsic electronic properties of pristine WS 2 alone are not sufficient to explain the observed high sensitivity towards H 2 S. A major role in this behavior is also played by O doping in the S sites of the WS 2 lattice. The results of the present study open up new avenues for the use of transition metal disulfide nanomaterials as effective alternatives to metal oxides in future applications for industrial process control, security, and health and environmental safety.