Green Route Biosynthesis of Shape‐Tunable ZnO Nanostructures and Their Photocatalytic Applications

Abstract

Herein, we report the synthesis of ZnO nanostructures of different morphologies via a facile and efficient wet chemical approach using flower extract as capping agent under ambient conditions. The purified samples were characterized via UV‐vis spectroscopy, photoluminescence spectroscopy, X‐ray diffractometry, electron microscopy, and thermogravimetric analysis. The diffractograms revealed that the products are pure and are well crystallized in a hexagonal wurtzite structure. The electron microscopic results confirmed that varying the concentration of flower extract, size and shape of ZnO nanostructures could be tuned. Microscopic results also clearly revealed that the flower like three dimensional morphologies of ZnO transforms gradually to spherical shape with increase in flower extract concentration. The ZnO nanostructures exhibit excellent photocatalytic activities towards the degradation of cationic dyes such as methylene blue and rhodamine B under UV light irradiation indicating that the flower extract derived ZnO architecture is a promising material for removal of pollutants from waste water. The effect of reaction parameters such as shape, size and amount of catalyst on the photocatalytic degradation of dyes were also studied. The results revealed that the maximum decolorization of dyes occur with ZnO photocatalyst at basic pH under UV light irradiation. The ZnO nanostructures are highly stable and are reusable for successive batches without losing any photocatalytic activity.

Green synthesis of CuO nanoparticles using Lantana camara flower extract and their potential catalytic activity towards the aza-Michael reaction

“…The phytochemicals were isolated from plant materials following our previously reported method. 32 The isolated dried mass was used to prepare a solution of 2.5 wt% extract in water.…”

Green synthesis of shape-tunable CuFe2O4NPs: a magnetically retrievable and efficient catalyst for Chan–Lam type C–N coupling reactions under base-free conditions

“…The phytochemicals were isolated from the plant materials following our previously reported method. 41,42 Briefly, the collected flowers of the Lantana camara plant were washed with water and then allowed to dry in the shade and ground into powders with the help of a grinder (Bajaj GX11). The ground Lantana camara flower powder (50 g) was taken in a Soxhlet apparatus and extracted with 500 mL methanol at 60 1C for 6 h. After extraction, methanol was evaporated in a rotary evaporator (Buchi RII) to isolate the solid phytochemicals.…”