Low temperature pH dependent synthesis of flower-like ZnO nanostructures with enhanced photocatalytic activity

In the present study we have synthesized flower-like ZnO nanostructures comprising of nanobelts of 20 nm width by template and surfactant free low-temperature (4 °C) aqueous solution route. The ZnO nanostructures exhibit flower-like morphology, having crystalline hexagonal wurtzite structure with (0 0 1) orientation. The flowers with size between 600 and 700 nm consist of ZnO units having crystallite size of ∼40 nm. Chemical and structural characterization reveals a significant role of precursor:ligand molar ratio, pH, and temperature in the formation of single-step flower-like ZnO at low temperature. Plausible growth mechanism for the formation of flower-like structure has been discussed in detail. Photoluminescence studies confirm formation of ZnO with the defects in crystal structure. The flower-like ZnO nanostructures exhibit enhanced photochemical degradation of methylene blue (MB) with the increased concentration of ligand, indicating attribution of structural features in the photocatalytic properties.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideResearch highlights► Low temperature (4 °C) synthesis of flower-like ZnO using zinc acetate and ethanolamine. ► Reactant ratio, pH and temperature determine the crystallinity and morphology of ZnO. ► ZnO synthesized with increasing reactant ratio shows enhanced photocatalytic activity. ► Enhanced photocatalysis is due to increase in surface area and surface defects.