ZrO2 nanoparticles were prepared modified sol–gel method. A 10 g zirconium(IV) propoxide was dissolved 20 ml ethanol (95%), 10 ml HCl (5%), and 40 ml double-distilled water to form a clear zirconium sol. Then, we add ammonia solution (25%) to form zirconium hydroxide precipitated. After washing, separation and drying of the precipitate overnight at 100 °C, the sample was calcined at 550 °C for 5 h to produce ZrO2 nanoparticles assigned as ZrO2.