New insights on physico-chemical transformations of ZnO: From clustered multipods to single crystalline nanoplates

Physico-chemical transformations of ZnO have been investigated in low temperature reflux reactions involving zinc nitrate, hexamethylene tetramine and cetyl trimethyl ammonium bromide. The stability features of various ZnO micro/nano structures were systematically examined from 4 to 60 h. The study showed the formation and transformation of multidimensional ZnO structures such as multipods, microtubes, microplates, nanoplates, nanoflowers, nanoblades and diffused nano networked structures including single crystalline nanoplates in a simple reflux synthesis. The crystalline nature, phase purity, associated structural features and surface characteristics were studied using powder X-ray, Raman, SEM, TEM, AFM, FT-IR, XPS and TG analytical techniques and the results were discussed. The kinetics involved in the evolution of ZnO structures and % yield of the ZnO products has also been studied and a possible growth mechanism is proposed on the basis of time-triggered transformations. The inherent anisotropic nature of ZnO as well as the change in chemical environment over the time of reflux is found to control the growth and evolution of diverse ZnO morphologies.