Morphology Dependent Photocatalytic Properties of ZnO Nanostructures Prepared by a Carbon-Sphere Template Method

Organic contaminants are a typical byproduct of industrial wastewater, and nanostructured ZnO photocatalysts have been investigated as an environmentally benign process to remove the contaminants through a degradation process. The degradation efficiency under UV irradiation can be markedly enhanced when using a catalyst with a nanostructure. The larger specific area of a nanostructure has been found to significantly enhance degradation efficiency. The complex synthesis process, expensive material costs, and generation of environmental contaminants during the synthesis process currently hinder practical application of photocatalysts. This research provides a template for a photocatalyst that is non-toxic, producing mesoporous ZnO hollow spheres and nanorods through an environmentally friendly carbon-sphere template utilizing a hydrothermal process. This research demonstrates that controlling the precursor concentration (zinc acetate) allows for the manipulation of the morphology and specific area of the ZnO nanostructures. A zinc acetate concentration of 0.171 mol/L produced uniform ZnO mesoporous hollow spheres with diameters of approximately 180 nm. Increasing the zinc acetate concentration resulted in an increase in the number of nanorods present. In contrast to nanorods, mesoporous ZnO hollow spheres have a higher specific area and higher concentration of pores in the 2-50 nm range, which result in better photocatalytic activity. This research reports the complete degradation of rhodium boride (RhB) within 50 min by means of mesoporous ZnO hollow spheres and nanorods with a degradation rate of 0.0978 min-1.