Tin Disulfide Nanotubes.

  A team of researchers led by Wolfgang Tremel at Johannes Gutenberg University Mainz have now developed a new technique for producing tin disulfide nanotubes. According to the report published in the journal Angewandte Chemie, the scientists have found a way of 'growing' SnS2 tubules from a metal droplet.

Synthesis
   They first used the vapour-liquid-solid (VLS) process, a technique more commonly used to produce semicon-ductor nanowires. Bismuth powder is combined with tin disulfide nanoflakes, and the mixture is heated in a tube furnace under an argon gas flow. The product of the reaction is deposited at the cooler end.

 Nanodroplets of bismuth are formed in the furnace, and these act as local collec-tion points for tin. In this manner, the reaction partners accumulate in the metal droplets, providing the raw material from which nanotubes can be grown. Tremel explains: "In this process, the metal droplets are retained in the form of spheres at the end of the tubes, while the nanotubes grow out of them like hairs from follicles. And thanks to the catalytic effect provided by the metal droplets, it is possible to grow nanotubes even at relatively low temperatures."

Using the new technique, the team has been able to produce perfect nanotubes with diameters in a range of 30 - 40 nm and lengths of 100 - 500 nm consisting of several layers of SnS2.
 [Source : azonano ]