In this article, environmentally compatible, low cost and easy green synthesized pure and Al-doped ZnO nanoparticles from the Azadirachta indica leaves extract were prepared. The greenly produced nanoparticles were mainly studied for structural properties. The x-ray diffraction data show that these were crystalline with the hexagonal wurtzite phase. The average crystallite size and some other important physical parameters such as stress, strain and energy density were estimated from the Williamson Hall analysis with the help of Rietveld refinement data. It was observed that with increasing Al-concentration, the crystallite size decreased but the other parameters like stress, strain and energy density increased. It was also seen that with increasing Al addition from 0%–15% the inter-planar spacing d hkl for each hkl set of the samples first decreased and then increased, which indicates the influence of the smaller size of Al ion addition on the inter-planar distance.

On page 5, the formula 'β s ≈ε/tan θ' would be replaced by the formula 'β s ≈εtan θ'. The slash symbol between the epsilon (ε) and tan θ would be removed.

Tetragonal zirconia (t‐ZrO2) nanoparticles (NPs) were successfully synthesized by a green method using β‐cyclodextrin as stabilizer. The structural characterization of the prepared nanoparticles was done by X‐ray diffraction (XRD).The tetragonal crystalline structure of ZrO2 NPs was confirmed by XRD analysis. We employed the Rietveld method to refine the XRD data and the refinement result leads to specify the tetragonal phase of ZrO2 NPs with space group P 42/n m c. The FTIR spectrum gives the information about the presence of Zr−O bonding at 501 cm−1. Particle size and morphological properties were demonstrated by Scanning Electron Microscope (SEM) and elemental compositions were analysed using EDAX spectrum. The band gap energy was estimated using optical absorption spectroscopy and the value was found to be 3.99 eV. The UV (310 nm) and visible (401, 420 and 560 nm) emissions were observed from PL spectrum. Brunauer‐Emmet‐Teller (BET) surface analysis was used for determining the surface area and average pore size of ZrO2 NPs.The photocatalytic degradation of the prepared ZrO2 NPs for organic dyes had been studied under visible light irradiation. Results showed that 68 % degradation was achieved within 135 min for Methylene Blue (MB) dye but other dyes almost remains unchanged during the same reaction times.

Zinc Oxide (ZnO) nanostructure doped with manganese (Mn: 5% and 10%) were prepared by the green synthesis method using the leaf extracts of Azadirachta indica. The microstructural investigation of the prepared nanopowders was carried out with the Rietveld refinement of the X-ray diffraction data. The phase analysis of the X-ray diffraction data confirmed that the synthesized nanoparticles have the hexagonal wurtzite structure in all cases. The Williamson Hall method was used to analyze the data obtained after the Rietveld refinement analysis to find some important microstructural parameters such as crystallite size, strain, stress and energy density. The size of the crystallites is almost the same in both cases and the values for strain, stress, and energy density increase with increasing Mn concentration. Functional groups and molecular interactions were identified by the Fourier Transform Infra-Red spectroscopy spectra. UV-visible spectra show that the band gap energy decreases with increasing Mn content. This property can help to fabricate a photodetector that can operate at a wavelength longer than the cut-off wavelength of ZnO. The morphology of the synthesized nanostructure was studied by field emission scanning electron microscope. The energy dispersive X-ray spectroscopy data confirm the elemental compositions in the synthesized Mn-doped ZnO, which means that the desired nanostructures were successfully synthesized by the green method.

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