Low Cost, Fast Solution Synthesis of 3D Framework ZnO Nanosponges.

An efficient, template-free solution-chemical route to nanostructured ZnO sponges is presented: A mixture of Zn(NO)·6HO, Zn(OAc)·2HO, and triethanolamine in methanol was evaporated to a highly viscous liquid and rapidly heated to >200 °C for 1-3 min to achieve highly porous, nanocrystalline sponges of ZnO. The viscous precursor concentrate obtained on evaporation in air was characterized by TG, DSC, and IR spectroscopy, and the product ZnO sponges by XRD, SEM, TEM, and IR spectroscopy. The fast reaction forming ZnO started at 140 °C and finished within a few seconds.