Synthesis Of Inorganic Nanotubes Research Articles

Single- to Triple-Wall WS2 Nanotubes Obtained by High-Power Plasma Ablation of WS2 Multiwall Nanotubes

The synthesis of inorganic nanotubes (INT) from layered compounds of a small size (<10 nm in diameter) and number of layers (<4) is not a trivial task. Calculations based on density functional tight-binding theory (DFTB) predict that under highly exergonic conditions, the reaction could be driven into a “window” of (meta-) stability, where 1–3-layer nanotubes will be formed. Indeed, in this study, single- to triple-wall WS2 nanotubes with a diameter of 3–7 nm and a length of 20–100 nm were produced by high-power plasma irradiation of multiwall WS2 nanotubes. As target materials, plane crystals (2H), quasi spherical nanoparticles (IF) and multiwall, 20–30 layers, WS2 nanotubes were assessed. Surprisingly, only INT-WS2 treated by plasma resulted in very small, and of a few layers, “daughter” nanotubules. The daughter nanotubes occur mostly attached to the outer surface of the predecessor, i.e., the multiwall “mother” nanotubes. They appear having either a common growth axis with the multiwall nanotube or tilted by approximately 30° or 60° with respect to its axis. This suggests that the daughter nanotubes are generated by exfoliation along specific crystallographic directions. A growth mechanism for the daughter nanotubes is proposed. High resolution transmission and scanning electron microscopy (HRTEM/HRSEM) analyses revealed the distinctive nanoscale structures and helped elucidating their growth mechanism.

Synthesis of Inorganic Nanotubes

AbstractNanotubes constitute an exciting class of one‐dimensional nanomaterials of which carbon nanotubes are recognized widely as materials of importance. The possibility of having inorganic nanotubes was recognized early in the 1990s, accompanied by the report of nanotubes of MoS2 and WS2. Since then, nanotubes of several inorganic materials have been prepared and characterized. While nanotubes of metal chalcogenides and oxides form a high proportion of the inorganic nanotubes investigated hither to, nanotubes of many other materials have also been prepared and characterized. Several synthetic strategies including both physical and chemical methods have been employed, of which the use of templates, precursors, and hydro‐ or solvothermal methods are prominent. In this article, we shall present a brief account of the present status of the synthesis of nanotubes of elemental materials as well as binary and complex metal oxides, chalcogenides, pnictides and carbides.

Recent Progress in the Study of Inorganic Nanotubes and Fullerene-Like Structures

The synthesis of WS2 inorganic nanotubes (INT) and inorganic fullerene-like (IF) structures in 1992 signified the opening of a fertile and challenging field of scientific endeavor. These structures were the first of a long and ever-expanding series of INT and IF structures. Although initially much of the effort concentrated on the synthesis of INT and IF from compounds with layered structures, recently there has been a surge of efforts to synthesize crystalline and polycrystalline nanotubular structures from compounds with quasi-isotropic structures, like spinels, BaTiO3, SiO2, TiO2, and many others. The present review summarizes some of the progress in this field in recent years. Much of the progress in this field was achieved through strong interaction between theoretical and experimental work. This article has four themes: (a) new synthetic approaches leading to new kinds of IF and INT; (b) study of the molecular structure of such nanoparticles with new tools, such as aberration-corrected transmission electron microscopy (TEM) and high-angle annular dark field (HAADF); (c) recent progress in the investigation of the properties of such nanostructures; and (d) examples of applications for which clear progress has been accomplished, in particular in solid lubrication and high-strength nanocomposites.

Inorganic Nanotubes and Fullerene‐like Nanoparticles

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Inorganic nanotubes and fullerene-like nanoparticles

We have proposed in 1992 that nanoparticles of layered compounds will be unstable against folding and close into fullerene-like structures and nanotubes (IF). Nanotubes and fullerene-like structures were prepared from numerous compounds with layered and recently also non-layered structure by various groups. Much progress has been achieved in the synthesis of inorganic nanotubes and fullerene-like nanoparticles of WS2 and MoS2 and many other metal dichalcogenides over the last few years. Substantial progress has been accomplished in the use of such nanoparticles for tribological applications and lately for impact resilient nanocomposites. These tests indicated that IF-MoS2 and IF-WS2 are heading for large scale applications in the automotive, machining, aerospace, electronics, defense, medical and numerous other kinds of industries. A few products based on these nanoparticles have been recently commercialized by “ApNano Materials, Inc”. Novel applications of inorganic nanotubes and fullerene-like nanoparticles in the fields of catalysis; microelectronics; Li rechargeable batteries; medical and opto-electronics will be discussed.

Advances in the Synthesis of Inorganic Nanotubes and Fullerene‐Like Nanoparticles.

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Advances in the synthesis of inorganic nanotubes and fullerene-like nanoparticles.

In analogy to graphite, nanoparticles of inorganic compounds with lamellar two-dimensional structure, such as MoS(2), are not stable against folding, and can adopt nanotubular and fullerene-like structures, nicknamed inorganic fullerenes or IF. Various applications for such nanomaterials were proposed. For instance, IF-WS(2) nanoparticles were shown to have beneficial effects as solid lubricants and as part of tribological surfaces. Further applications of IF for high-tensile-strength fibers, hydrogen storage, rechargeable batteries, catalysis, and in nanotechnology are being contemplated. This Minireview highlights some of the latest developments in the synthesis of inorganic nanotubes and fullerene-like structures. Some structural aspects and properties of IF, which are distinct from the bulk materials, are briefly discussed.