Synthesis, fundamental properties and applications of nanocrystals, sheets, nanotubes and cylinders based on layered transition metal chalcogenides

Folded and disordered MoS₂ and other transition metal chalcogenides such as WS₂ and ReS₂ have two-dimensional layered structures. A consequence of this two-dimensional macromolecular nature is the existence of highly folded and disordered structures. These structures have been recognized for a long time as `rag' and `tubular' structures and are useful as catalytic materials. More recently, formation of nanotubes and nested nanotubes of WS₂ and MoS₂ have been reported and described as large fullerene-like structures. The ability of MoS₂ and related compounds to form these structures remains unclear and is the subject of intense study. The study of these materials has been hindered by the inability to synthesize them in large quantities. This situation is similar to early days of research in fullerenes that progressed slowly until improved synthetic methods led to larger quantities being available. The purpose of this report is to review the synthesis of `rag' and `tubular' MoS₂ and related materials and to discuss recent results.