Syntheses of ZnO and ZnO-coated TiO2 nanoparticles in various alcohol solutions at multibubble sonoluminescence (MBSL) condition

Syntheses of zinc oxide (ZnO) and ZnO-coated titanium dioxide nanoparticles under ultrasonic field at the multibubble sonoluminescence (MBSL) condition were tried in various alcohol solutions. The MBSL condition facilitates the supercritical state of liquid layer where high-energy chemical reaction in the layer around the bubble is possible. At the optimal MBSL condition in alcohol solutions containing zinc acetate dehydrate of 2.75 wt%, sodium hydroxide of 1 wt% and TiO2 of 1 wt%, ZnO nanoparticles having the average diameter of 7 nm were synthesized first and subsequently ZnO-coated TiO2 nanoparticles were synthesized within 10 min. The prepared particles of ZnO and ZnO-coated TiO2 were examined by XRD, UV–vis spectrophotometer and HR-TEM.