Growth and photocatalytic properties of one-dimensional ZnO nanostructures prepared by thermal evaporation

Aligned ZnO nanorods and nanotubes were grown on the silicon substrates by thermal evaporation of high pure zinc powders without any other metal catalyst. The morphology evolution of ZnO nanostructures with prolonged growth time suggested that the growth of the ZnO nanorods and nanotubes follows the vapor–liquid–solid mechanism. ZnO nanoneedle and nanoparticle films were also synthesized by the same way, and their photocatalytic performances were tested for the degradation of organic dye methylene blue. The ZnO nanoneedle films exhibited very high photocatalytic activities. The decomposition kinetics of the organic pollutant was discussed. Moreover, it is found that the ZnO nanoneedle films showed very stable photocatalytic activity.