Supercritical antisolvent precipitation of nanoparticles of a zinc oxide precursor

Supercritical antisolvent (SAS) precipitation has been applied to the produ ction of zinc acetate with the aim of evaluating the applicability of this new process to the production of controlled size nanoparticles of catalyst precursors. SAS process is based on the large volumetric expansion of the l iquid solvent induced by the fast diffusion of the antisolvent inside the l iquid phase. The main process parameter that controlled zinc acetate partic le size and particle size distribution (PSD) was the concentration of the l iquid solution. Zinc acetate nanoparticles with sizes down to 30 nm and wit h a mean particle size of 50 nm have been produced. The nanoparticles showe d different porosities depending again on the concentration of the liquid s olution. BET surface areas up to about 175 m(2)/g were measured using N-2 a dsorption. (C) 1999 Elsevier Science S.A. All rights reserved.