Morphology Controlled Synthesis of Zinc Oxide Nanostructures Through Millettia pinnata (MP) Leaf Extract as Capping Agent and its Photocatalytic Degradation Efficiency of a Textile Dye

Abstract

The present work reports low cost, rapid synthesis of ZnO nanostructures capped with Millettia pinnata leaf extract which produced rods, pyramids, cones and flower like morphology. Microwave irradiation method drastically reduced the reaction time. Three samples were prepared with different volumes of the extract and a control experiment was performed where no extract was used. The quantity of the extract significantly influences the size and morphology. Characterization done by X-ray diffraction established the purity and crystalline nature of the samples. The composition was further confirmed by EDS which shows the exclusive presence of elements zinc and oxygen. UV–visible spectroscopy shows absorption wavelength for the as synthesized ZnO semiconductor samples between 351 and 365 nm. FTIR spectra show a band in the region of 500–550 cm−1 corresponding to Zn–Ostr. FESEM images show rodlike morphology for uncapped ZnO which on annealing at 400 °C produced an assembled flower like morphology. The morphology varies from pyramid, to cone, to flower like as the volume of extract increases from 2.5 to 10 mL. Methylene blue was the target textile dye and its degradation was tested under UV light.