In situ mixed potential study of the growth of zinc oxide hierarchical nanostructures by wet oxidation of zinc foil

Hierarchical zinc oxide (ZnO) nanostructures were successfully grown by oxidation of etched Zn foil in water at 90 A degrees C. The morphology of the ZnO nanostructures evolved from nanorods to hexagonal nanotubes then to flower-like structures with continued oxidation. Etching of the foil possibly promotes the growth of these ZnO nanostructures by creating inhomogeneities on the surface of the foil, which act as nucleation sites. In situ mixed potential measurement in combination with thermodynamic calculation was performed to elucidate the effect of temperature on the formation of the ZnO hierarchical nanostructures. The mixed potential increased with higher oxidation temperatures, suggesting enhanced oxidation.