New reactor for production of tungsten disulfide hollow onion-like (inorganic fullerene-like) nanoparticles

MS2 (M = Mo, W) hollow onion-like nanoparticles were the first inorganic fu llerene-like (IF) materials, found in 1992. Understanding of the IF-MS2 gro wth mechanism in 1996 enabled us to build a rather simple reactor, which pr oduced about 0.4 g per batch, of an almost pure IF-WS2 powder. Soon after, it was found that the new powder showed better tribological properties comp ared with the regular MS2 (M = Mo, W) powder, which is a well-known solid l ubricant. The present work shows a new synthetic approach, which allows for a scale up of IF-WS2 production by more than two orders of magnitude. The falling-bed and, especially, fluidized-bed methods, which are presented her e, pave the way for an almost ideal growth condition of the IF synthesis fr om an oxide precursor. As a result, the presently produced IF has a more un iform (spherical) shape and can grow to a larger size (up to 0.5 mum). It i s expected that the relatively spherical IF-WS2 nanoparticles, which are pr oduced by the falling (fluidized) bed reactor, will exhibit superior tribol ogical properties, than reported before. (C) 2000 Editions scientifiques et medicales Elsevier SAS. All rights reserved.