SUBMICROMETER ZINC-OXIDE PARTICLES - ELABORATION IN POLYOL MEDIUM AND MORPHOLOGICAL-CHARACTERISTICS

A novel and easy route for preparing submicrometer particles of zinc oxide, involving hydrolysis of zinc salt in a polyol medium, is proposed. Zinc acetate dihydrate and diethyleneglycol appear to be the best candidates for obtaining a high yield of particles with well-defined morphological characteristics. Monodisperse spherical particles in the submicrometer range (0.2 - 0.4 mum) have been obtained for a salt concentration less than 0.1 mol 1(-1). The particle size depends mainly on the heating rate. The particles are microporous (surface area: 80 m2 g-1) and are formed by aggregation of small crystallites (10 nm). Calcination at moderate temperature drastically reduces this porosity without significant interparticle sintering. At higher concentration, no aggregation occurs and tiny single crystallite particles are obtained.