Formation of porous spherical aggregated structure of ZnO nanoparticles by low-temperature heating of Zn(OH)2 in diol solution

Zinc oxide (ZnO) nanoparticles were obtained by heating Zn(OH)2 in a diol solution. When ethylene glycol, 1,3-propanediol and 1,4-butanediol were used for the heat treatment of Zn(OH)2, ZnO nanoparticles can be obtained by heating at more than 308 K. In particular, when ethylene glycol was used for the heat treatment of Zn(OH)2, the stable sols with the dispersion of the ZnO nanoparticles whose average diameter was less than 20 nm were obtained. Furthermore, when the heating temperature was 308 K, the spherical secondary particles with ZnO primary nanoparticles were obtained. The porosity in the secondary particles can be controlled by the diol solution used for heating of Zn(OH)2.