Hydrothermal synthesis of different colors and morphologies of ZnO nanostructures and comparison of their photocatalytic properties

Various zinc oxide nanostructures were synthesized using thermal decomposition of zinc acetate dihydrate in a single process. The characterization of samples using powder X-ray diffraction, scanning electron microscope and FT-IR measurements revealed that the pure phase of different morphologies such as nanoparticles, nanowires and nanodisks had been synthesized successfully. Surprisingly some synthesized ZnO nanostructures were dark gray. The results showed that the reason may have been related to the oxygen deficiency and strong asymmetric stretching mode of wurtzite ZnO nanostructure. Using such samples, the photodegradation of Methylene blue was performed by UV–vis absorption measurement and the effect of morphology on the photocatalytic properties of different ZnO nanostructures was examined. The results showed that the nanodisks had the best photocatalytic performance among the other morphologies. The reason was attributed to the presence of specific crystal planes such as (0001) facets in nanodisks which can improve their photocatalytic performance.