Preparation And Catalytic Property Of Structure Oriented ZnO

Nanostructure zinc oxides (ZnO) on the zinc foils have been combined by thermal oxidation and low-temperature wet-chemical approach. XRD, SEM, DRS are used to characterize the structure and surface chemical-physical properties of the prepared samples. It is indicated that hexagonal ZnO particle-film can be prepared by thermal oxidation method at different temperatures, whereas, highly oriented ZnO nanorod arrays with hexagonal wurtzite structure are formed by the latter two methods on the zinc foils. It is also found that ZnO nanorods with 100 nm-150 nm in diameter grow highly epitaxial along the c-axis orientation. Moreover, the approach combining thermal oxidation and wet-chemical favors the formation of the denser, ordered epitaxial ZnO nanorods on the surface of zinc foil. Photoluminescence spectra of ZnO nanorod array films with excitation wavelength 350 nm are measured at room temperature. Three emission bands are observed, one being a narrow violet band with central wavelength of 386 nm and the other being wide visible bands with central wavelength of 524 nm, 450 nm, respectively. The room temperature photolum inescence of the as-prepared ZnO films exhibits a strong UV emission at about 379 nm and a weak emission at about 450 nm.The catalytic activities of the as-prepared ZnO are evaluated for the photodegradation of methyl orange in aqueous solution. It is revealed that the reaction follows the first-order reaction kinetics. And ZnO nanorods prepared by the wet-chemical approach followed thermal oxidation at 350oC show the best activity for the photodegradation of dye solution, and the highest photoabsorption ability in our case. It could be resulted from the restraint on the recombination of photo hole/electron after the sample is treated by thermal oxidation at appropriate temperature. The photocatalytic reaction follows the first-order reaction kinetics and the constant of apparent rate is related to the initial concentration of methyl orange.In conclusion, ZnO nanorod arrays with high activity are fabricated on the zinc foils using a cheap and simple low-temperature route. It is a potential approach to develop highly efficient photocatalyst.