Impacts of the reactants on the synthesis of ZnO particles in glycerol-based solvents

Abstract

Particles composed of zinc oxides were prepared by changing the synthesis parameters in a glycerol-based solvent. By varying the mole ratio of zinc nitrate and sodium hydroxide in a glycerol–urea solvent, unexpected Zn₅(OH)₈(NO₃)₂·2H₂O intermediate and ZnO wurtzite phases were identified at different percentages depending on the reactant stoichiometry and temperature. Exchanging urea for isopropanol, tetramethyl urea, dimethylurea, thiourea, and ammonia gas provided different resultant materials. Dimethylurea and tetramethyl urea led to ZnO nanoparticles though passing through the usual Zn(OH)₂ intermediate, whereas thiourea formed only ZnS nanoparticles. Glycerol–isopropanol (GI) yielded ZnO nanoparticles with a small size distribution over a range of GI molar ratios. Bubbling ammonia into glycerol formed needle-shaped ZnO particles. These outcomes highlight the valuable synthetic potential of glycerol-based solvents that allow for highly efficient synthesis of tailored zinc-made particles with easy and mild work-up.