Department Of Chemistry

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Subject: search.filters.subject.Azadirachta indica

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    Green Approach for the Fabrication of Au/ZnO Nanoflowers: A Catalytic Aspect
    (American Chemical Society, 2021-03-19T00:00:00) Biswas, Rathindranath; Banerjee, Biplab; Saha, Monochura; Ahmed, Imtiaz; Mete, Shouvik; Patil, Ranjit A.; Ma, Yuan-Ron; Haldar, Krishna Kanta
    An easy, environmentally benign, and biomimetic approach employing Azadirachta indica (neem) leaf extract as a reducing as well as capping agent was used for the fabrication of gold (Au)/zinc oxide (ZnO) hybrid nanoflowers in one pot without utilizing any hazardous chemicals. The different phytoconstituents, for example, nimbolide, azadirachtin, ascorbate, etc., present in A. indica (neem) leaf extract synergistically reduce gold(III) ions to gold(0), which later on acts as an active surface for the growth of zinc oxide (ZnO) via thermal decomposition of sodium zincate [Na2Zn(OH)4]. The development of Au/ZnO hybrid nanoflowers was observed by estimating the absorption maxima at various time intervals in the wake of adding a Au precursor to the aqueous extract. X-ray diffraction (XRD) studies and X-ray photoelectron spectroscopy (XPS) investigation unambiguously confirm the formation of highly crystalline Au/ZnO composed of Au(0) and ZnO. The as-synthesized Au/ZnO hybrid nanoflowers were analyzed utilizing different spectroscopic and microscopic techniques. The transmission electron microscopy (TEM) images clearly show that the synthesized hybrid Au/ZnO nanoflowers are monodisperse and uniform. The fabricated Au/ZnO nanoflowers were used as a catalyst for the efficient reduction of various aromatic nitro compounds to corresponding amino compounds with excellent yield (76-94%) in the presence of reducing agent sodium borohydride. The superior catalytic properties were credited to the extraordinary nanoflower morphology and the synergistic impact of the typified Au nanoparticles. � 2021 American Chemical Society.
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    Fabrication of mesoporous titanium dioxide using azadirachta indica leaves extract towards visible-light-driven photocatalytic dye degradation
    (Elsevier, 2020) Dash, L; Biswas, R; Ghosh, R; Kaur, V; Banerjee, B; Sen, T; Patil, R.A; Ma, Y.-R; Haldar, K.K.
    An environmental benign, straightforward and financially savvy technique has been developed to fabricate mesoporous titanium dioxide (TiO2) nanostructure utilizing Azadirachta indica leaves extract. The aqueous extract of Azadirachta indica leaves act as a template which upon calcination at high temperature generated mesoporous TiO2. The structure of the mesoporous TiO2 was confirmed by X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy and isothermal gas adsorption-desorption (BET). It has been found that the crystallinity and pore diameter of mesoporous titanium dioxide (TiO2) depends on the amount of Azadirachta indica leaves extract, resulting in enhanced crystallinity with an increasing amount of Azadirachta indica leaves extract. The pore diameter was found somewhere in the range from 16.67 to 46.19 nm, and the BET surface area varies from 8.55–157.35 m2/g.. Finally, we have explored as-synthesized mesoporous TiO2 for visible-light-driven photocatalytic degradation of rhodamine 6 G (R6 G) dye. It is noteworthy that the photocatalytic degradation rate of R6 G in presence of as-synthesized mesoporous TiO2 depends only on the amount of plant extract used and not on temperature and other factors. This is presumably due to the increased optical band gap of TiO2. - 2020 Elsevier B.V.