Highly active ZnO rod-like nanomaterials: Synthesis, characterization and photocatalytic activity for dye removal

Highly active ZnO rod-like nanostructures with pointed-shape ends have been synthesized via a simple hydrothermal method using acetic acid as an organic capping agent. The X-ray diffraction (XRD) pattern of the prepared sample reveals that the ZnO rod-like nanostructures are of pure hexagonal wurtzite structure. Morphology of the nanorods has been investigated by transmission electron microscope (TEM), which showed the formation of pointed nanorods of 30–50 nm in diameter and 400–650 nm in length. Optical properties have been investigated by UV–vis diffuse reflectance and photoluminescence spectroscopy. UV–vis absorption spectrum indicated that the ZnO nanorods have higher visible light harvesting as compared to the other morphologies in the literature. Intense room temperature green-red photoluminescence peaks at 486 nm and 564 nm has been observed for the prepared ZnO. This gives a good evidence of the presence of ionized oxygen vacancies which are favorable for photocatalytic reactions. The BET surface area and the average (BJH) adsorption pore size were 269.86 m2/g and 2.86 nm, respectively. The photocatalytic activity of the prepared sample was tested on the degradability of an industrial textile dye, Reactive Yellow 15 (Yellow GR), under sunlight irradiation. A 85.7% dye removal was achieved by applications of these rod-like nanostructures as a photocatalyst.The reusability of the synthesized ZnO nanomaterial has been investigated under the same experimental conditions for three time to evaluate the photoactivity of the photocatalyst.

Graphical AbstractHighly active ZnO rod-like nanomaterial with high surface area and excellent optical properties were successfully obtained by simple hydrothermal methods that based on acetic acid as a new capping agent. It showed a remarkable photocatalytic activity in the environmental clean-up from hazardous dye pollutants from water extremes under natural sunlight irradiation.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Facile hydrothermal synthesis of ZnO rod-like nanomaterials. ► Photoluminescence and optical properties of the prepared ZnO nanopowder. ► N2 adsorption/desorption isotherm and pore size distribution of the ZnO nanorods. ► Solar photocatalytic activity of the obtained ZnO on the “Yellow GR” dye removal.