Low‐Temperature Synthesis of Zinc Oxide Nanoparticles

Crystalline zinc oxide nanoparticles have been prepared by mixing aqueous solutions of zinc nitrate and hexamethylenetetramine (HMT) at 60°C and 80°C. Transmission electron microscopy and X‐ray diffraction show that the ZnO nanoparticles of diameters ranging from 15–33 nm and 25–43 nm long are formed. Aspect ratio is observed to range from 1.18 to 1.74 at 60°C and 1.22 to 1.70 at 80°C as the HMT to zinc nitrate concentration ratio increases from 10 to 150. Nanoparticle size decreases as the concentration of HMT increases. Much larger ZnO particles are formed with ammonium hydroxide as a hydrolysis agent without HMT. In summary, HMT is an ammonium‐hydroxide source in the reaction, a surfactant for retaining nanosize, and not necessarily a template for ZnO nucleation.