Controlled preparation of hollow zinc oxide microspheres from aqueous solution using hexamethylenetetramine and cysteine

Zinc oxide particles were synthesized by precipitation from an aqueous solution of zinc nitrate tetrahydrate, R-(+)-cysteine and hexamethylenetetramine (HMTA, urotropine). Hollow microspheres of ZnO–cysteine hybrid material with a diameter of ca. 1 μm and a wall thickness ca. 50 nm were obtained. After heating up to 850 °C pure ZnO microspheres of roughly the same size were formed. The particles were characterized by XRD, SEM, FT-IR and TGA.