Vertically aligned zinc oxide nanosheet for high-performance photocatalysis of water pollutants

Abstract

Abstract The present work is focused on the synthesis of morphology-controlled vertically aligned Zinc oxide (ZnO) nanosheets (NSs) using a high power low-temperature sonochemical process. The synthesis process is a facile and low-temperature process, which can be able to produce large-area, homogeneously-grown, vertically-aligned ZnO NSs with high surface to volume ratio. Also, using the same process, we have developed a low-temperature in-situ method of the magnesium (Mg), doped ZnO NSs with identical structure and morphology. The process is versatile, scalable and can be adopted for synthesizing various other doped morphology controlled nanosheets synthesis. The morphology and structure were confirmed using X-ray diffraction technique, FESEM, TEM/HRTEM while surface composition, bonding and doping were confirmed using XPS and UV–VISIBLE spectroscopy. We obtained 2D few layered thick ZnO nanosheets of flake size 2–5 μm with bandgap ∼3.38 eV, which was increased to ∼3.7 eV due to the Mg doping. Furthermore, we demonstrated the comparative photocatalytic activity of the as-synthesized pristine and doped ZnO nanosheets and found that Mg-doping promotes the faster catalytically active redox reaction, hence; the dye degradation time was 15 min faster compared to the pristine ZnO NSs under identical conditions. We believe that the rate-enhancement in photocatalytic dye degradation of Mg-doped ZnO NSs is obtained due to the faster hole transport properties and low recombination rate.