Preparation and photocatalytic property of preferred-oriented ZnO nanorod array films

By using a simply and low-temperature wet-chemical method, ZnO nanorod array films with preferred orientation consistence are prepared on a zinc metal. Scanning electron microscopy (SEM), X-ray diffraction (XRD) and Photoluminescence (PL) technique are used to characterize the ZnO nanorod arrays. The results show that ZnO nanorods are hexagonal wurtzite structures with highly oriented ZnO (002) crystal face, which indicate that as-prepared films were highly c-axis oriented. SEM images show that more than 90% ZnO nanorods have diameter of 80 to 140 nm and the typical length is about 4 μm. 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, 450 nm, respectively. Photo degradation of methyl orange in aqueous solution is investigated by using the ZnO nanorods as a photocatalyst. The photocatalytic reaction follows the first-order reaction kinetics and the constant of apparent rate is related to the initial concentration of methyl orange.