Influence of the mixing ways of reactants on ZnO morphology

Abstract

ZnO particles with various morphologies were synthesized by mixing ZnSO4 and NaOH solutions at 25°C followed by aging of the suspensions at 40-80°C for 2.0 h, keeping the initial molar ratio of Zn 2+ to OH- at 1: 4. ZnO irregular plates were prepared by adding NaOH to ZnSO4 while ε -Zn(OH)2 rhombic particles were produced using the opposite mixing way. After aging of the slurries at 80°C for 2.0 h, the ZnO plates were kept stable while the ε -Zn(OH)2 rhombic particles were converted to ZnO whiskers with a length of 1.0-4.0 m and a diameter of 0.03-0.3 m. Thermodynamic analysis indicated that the formation of the Zn-bearing precipitates (ZnO or ε -Zn(OH)2) at room temperature was connected closely with the solution composition. © 2013 Lining Yang and Lan Xiang.