Varying the microstructural properties of ZnO particles using different synthesis routes

The hydrolysis at 90 °C of zinc acetylacetonate [Zn(acac)2] in solutions containing sodium hydroxide and trisodium citrate was monitored using Raman and FT-IR spectroscopies and field emission scanning electron microscopy. The size and shape of the precipitated particles depended on the initial mole ratio [Zn(acac)2]/[Na3-citrate] and initial NaOH concentration. The conditions for precipitation of square plate-like particles or thin foils were determined. Nanosize ZnO particles of good uniformity were obtained by heating square plate-like particles or thin foils at 300 °C. With additional heating at 600 °C larger particles were obtained. These particles showed the Raman bands at 332, 384, 413, 438, 540 and 583 cm−1, which were assigned to wurtzite-type ZnO. For the initial mole ratio [Zn(acac)2]/[Na3-citrate] = 1:0.5 and at concentration of 1 × 10−2 M NaOH the ZnO particles of different shapes were obtained which consisted of primary nanosize particles with chemically bonded citrate groups.