Adjusting the proportions of {0001} facets and high-index facets of ZnO hexagonal prisms and their photocatalytic activity

Zinc oxide (ZnO) hexagonal prisms with unique nanostructures are successfully synthesized via a simple hydrothermal method with the assistance of polyethylene glycol (PEG). Further studies demonstrated that dissolved PEG played a critical role in adjusting the exposed proportion of {0001} facets and high-index facets. By increasing the amount of PEG, we successfully reduced the exposed proportion of {0001} facets and increased the exposed proportion of high-index facets. The morphology and the properties of ZnO hexagonal prisms were investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD), Brunauer-Emmett-Teller N-2 gas adsorption-desorption isotherms, and photoluminescence (PL) spectra. The photocatalytic activity of the ZnO hexagonal prisms was investigated by photocatalytic degradation of methylene blue (MB) aqueous solution under UV-vis light irradiation. Results showed that the ZnO hexagonal prism samples with a high percentage of exposed high-index facets exhibited superior photocatalytic activity. The idea that adjusting the proportion of different facets to enhance the photocatalytic activity of ZnO samples is a meaningful study.