Porous Zn1-xCuxAl2O4 (x = 0,0.1,0.2,0.3,0.4,0.5) spinel nanostructures were synthesized by onepot microwave combustion technique. All the samples were characterized using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), diffuse reflectance spectroscopy (DRS), photoluminescence (PL) and scanning electron microscopy (SEM). The XRD patterns confirm the formation of single phase ZnAl2O4 without any impurities. The results of XRD indicated the average crystallite size in the range of 12.44-22.86 nm. FT-IR spectra show the vibrational stretching frequencies corresponding to the zinc aluminate spinel structure. The estimated band gap of undoped ZnAl 2O4 was 4.96 eV indicating the quantum confinement phenomenon. DRS spectra also indicated the band gap narrowing effect with increase in copper ion concentrations. The defect centers acting as trap levels were obtained from photoluminescence studies responsible for the emission spectra. SEM images showed the features of well created pore structures in all the matrices. The percentage porosity of zinc aluminate matrices decreased with increasing copper doping. Copyright © 2013 American Scientific Publishers.

John Kennedy L

Physics

School of Advanced Sciences

Chennai Campus

Anand G.T

Vellore Institute of Technology (VIT) is a private university located in&nbsp;Tamil Nadu, India. Founded in 1984, as Vellore Engineering College, the institution offers 20 undergraduate, 34 postgraduate, four integrated and four research programs. It has campuses in Vellore, Amravati, Bhopal and Chennai.

VIT is one of the top ranked private universities in India according to NIRF, THE and QS Rankings.&nbsp;Govt. of India has recognized&nbsp;VIT, Vellore as an&nbsp;Institution of Eminence. This has allowed VIT to take independent quality initiatives and move up in world ranking.

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VIT University

Journal of Nanoscience and Nanotechnology

Barium doped La2CuO4 perovskite nanoparticles were synthesized via microwave assisted combustion method. The effects of Ba2+ doping on structural, optical, magnetic and catalytic activity of La2CuO4 have been studied by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), diffuse reflectance spectroscopy (DRS), scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX) and vibrating sample magnetometer (VSM) techniques. The XRD patterns of pure La2CuO4 and La1.9Ba0.1CuO4 confirmed the formation of perovskite structure without impurities. However, with increasing Ba2+ content in the range 0.2–0.5, phase transformation from orthorhombic to tetragonal structure, occurred. The average crystallite size of orthorhombic and tetragonal phases were in the range 45.2–52.2 nm and 0.5–41 nm, respectively. The appearance of FT-IR bands at around 685 and 517 cm−1 were correlated to the La-O and Cu-O stretching modes of orthorhombic La2CuO4 phase. The direct band gap estimated using Kubelka–Munk (K–M) method decreased with the increase in Ba2+ content (1.88–1.64 eV), due to the formation of sub-bands in the energy band gap. Magnetic measurements of doped La2CuO4 samples showed either para- or ferro-/para- magnetic behaviour at room temperature. The catalytic activity (oxidation) tests carried out in a batch reactor operating under atmospheric conditions indicated that the prepared catalysts, in particular (La1.7Ba0.3CuO4), showed excellent catalytic activity. © 2018 Elsevier Ltd and Techna Group S.r.l.

Ceramics International

Structural, magnetic and catalytic properties of La2-Ba CuO4 (0 ≤ x ≤ 0.5) perovskite nanoparticles

Co1-xCuxFe2O4 (0 ≤ x ≤ 0.5) nanoparticles were prepared by the microwave combustion technique. The obtained samples were characterized using X-ray diffraction (XRD) analysis, X-ray photoelectron spectroscopy (XPS), high resolution scanning electron microscopy (HR-SEM), energy dispersive X-ray (EDX) analysis, UV-visible diffuse reflectance spectroscopy, photoluminescence (PL) spectroscopy, Fourier transformed infrared (FT-IR) spectroscopy and vibrating sample magnetometry. The XRD result confirms the formation of cubic spinel structure and the average crystallite size was observed to be in the range of 46-31 nm calculated by Debye Scherrer's equation. XPS analysis was carried out to study the chemical elements and oxidation states of the synthesized Co1-xCuxFe2O4 (0 ≤ x ≤ 0.5) nanoparticles. The HR-SEM image showed agglomerated spherical nanoparticles and the elemental composition of copper doped cobalt ferrite was attained from energy dispersive X-ray analysis. The band gap energy was calculated by diffuse reflectance spectroscopy. Photoluminescence spectra showed the rate of recombination of electron-hole pairs and presence of defects. The band at 661 and 569 cm-1 is due to the intrinsic stretching vibrations of octahedral group complex of Co2+-O2- and Fe3+-O2- at tetrahedral sites. Remanence magnetization (Mr), coercivity (Hc) and saturation magnetization (Ms) were deduced from the hysteresis curves. The obtained Co1-xCuxFe2O4 (0 ≤ x ≤ 0.5) nanoparticles were assessed for the photocatalytic degradation of RhB under visible light. A possible mechanism responsible for photocatalytic degradation process is discussed. © 2017 Elsevier Ltd. All rights reserved.

Journal of Environmental Chemical Engineering

Photocatalytic removal of rhodamine B under irradiation of visible light using Co1Cu Fe2O4 (0 ≤x≤ 0.5) nanoparticles

Zn1−xNixO with 0 ≤ x ≤ 0.2 nanoparticles (NPs) were prepared by co-precipitation with subsequent annealing at 500 °C for 2 h. For a better control of particle's growth, a non-ionic surfactant namely Tween-80 was used during the preparation process. XRD Rietveld analysis confirmed the formation of the hexagonal wurtzite-type structure along with a secondary phase namely NiO. SEM observations revealed remarkable change in morphology, including rods, sheets and spheres. The purity of the as-prepared NPs as checked by EDAX analysis indicated that the chemical composition of Zn, Ni and O was in good agreement with the starting stoichiometries. The defect states were revealed from the UV and visible emissions of the photoluminescence spectra. The DRS analysis showed blue shift as Ni2+increases from 5 to 20%. The existence of a peak at 432 cm−1in FTIR spectra confirmed the formation of ZnO phase. The Magnetization-Field (M-H) curves revealed the existence of ferromagnetism in Ni-doped ZnO NPs, which was attributed to bound magnetic polaron (BMP) mechanism. © 2016 Elsevier B.V.

Journal of Alloys and Compounds

Optical and magnetic properties of Ni-doped ZnO nanoparticles

Zn1-xCuxO (0 ≤ x ≤ 0.2) nanoparticles were prepared by co-precipitation method followed by drying at 200 °C. A non-ionic surfactant Tween-80 which was not reported in earlier studies, was used during preparation process. X-ray diffraction analysis showed the formation of wurtzite ZnO phase nanostructures. The Rietveld analysis showed the appearance of impurity phase (CuO), when Cu2+ was doped with ZnO (x = 0.05 to 0.2). Morphological observations using scanning electron microscopy show the formation of nanoparticles with remarkable morphologies. Photoluminescence spectra revealed emission bands in both UV and visible regions due to the defect centres acting as trap levels. Diffuse reflectance spectroscopy (DRS) showed a decreasing trend in the value of the band gap with increasing Cu2+ doping for lower concentration (x = 0 to 0.1) and then increasing trend for higher concentration of Cu2+ doping. (x = 0.1 to 0.2). The elemental composition of Zn, Cu and O was quantitatively obtained from EDAX analysis where the chemical composition was close to the starting stoichiometries. Magnetisation-Field (M-H) hysteresis curves revealed the appearance of ferromagnetic behaviour, where the magnetic characteristics such as coercivity and saturation magnetization values, were found to be sensitive to Cu2+ doping level. © Copyright 2016 American Scientific Publishers.

Structural, Optical and Magnetic Properties of Cu-Doped ZnO Nanoparticles by Co-Precipitation Method

Pure and Mn2+ doped ZnO nanoparticles (Zn1-xMnxO with 0 ≤ x ≤ 0.2) were prepared by co-precipitation method followed by drying at 200°C. A non-ionic surfactant, Tween-80, was used during preparation process to control the particles growth. X-ray diffraction analysis revealed the formation of hexagonal wurtzite for pure and Mn2+ doped ZnO samples with a minor secondary phase. The Rietveld analysis confirmed the formation of hexagonal wurtzite structure as well as the secondary phase as Mn3O4 for all doping levels. Morphological observations showed the formation of nanoparticles with remarkable morphologies of which spherical nanostructures seem to be more dominant. The quantitative analysis from EDAX confirmed the purity of the as-prepared nanopowders and that the chemical composition of Zn, Mn and O seem to be close to the starting stoichiometries. Emission bands in both UV and visible regions were revealed by photoluminescence spectra, which were due to defect centers acting as trap levels. The diffuse reflectance spectroscopy (DRS) indicated a decrease in the value of bandgap with increasing Mn doping concentration. The ferromagnetic behaviour was very clear from the Magnetisation-Field (M-H) hysteresis curves, where the magnetic characteristics such as coercivity and saturation magnetization values, were found to be sensitive to Mn doping level. © 2016 Elsevier B.V. All rights reserved.

Journal of Molecular Structure

Structural, microstructural, optical and magnetic properties of Mn-doped ZnO nanostructures

Magnesium oxide (MgO) was synthesised by a simple microwave-assisted combustion route without using any template, catalyst or surfactant. For the purpose of comparison, it was also prepared using conventional method. The as-synthesized MgO was characterized by powder X-ray diffraction (XRD), Fourier Transform infrared spectra (FT-IR), high resolution scanning electron microscopy (HR-SEM), transmission electron microscopy (TEM), Energy Dispersive X-ray analysis (EDX), diffuse reflectance spectroscopy (DRS) and Photoluminescence (PL) spectroscopy. The XRD results confirmed the formation of cubic phase MgO. FT-IR was used to investigate the adsorption of water and CO2 on MgO surface and confirm the formation of Mg-O phase. The formation of MgO micro cubes structures was confirmed by HR-SEM. The formation of MgO nanosheets was confirmed by HR-SEM and TEM and their possible formation mechanisms were also proposed. The optical absorption and photoluminescence emissions were determined by DRS and PL spectra respectively. An attempt has been made to compare the lattice parameter and the PL intensity. © 2011 Elsevier B.V.

Comparative study of microwave and conventional methods for the preparation and optical properties of novel MgO-micro and nano-structures

Journal of Materials Science

ZnAl2O4 co-doped with Yb3+/Er3+ prepared by combustion reaction: evaluation of photophysical properties

Synthesis and characterization of nanosized zinc aluminate spinel from a novel Zn–Al layered double hydroxide precursor

International Journal of Hydrogen Energy

The design of a hierarchical photocatalyst inspired by natural forest and its usage on hydrogen generation

Journal of Luminescence

Synthesis, characterization and studies of radiative properties on Eu3+-doped ZnAl2O4

One-Pot Microwave Combustion Synthesis of Porous Zn1–xCuxAl2O4 (0 ≤ x ≤ 0.5) Spinel Nanostructures

Journal	Data powered by TypesetJournal of Nanoscience and Nanotechnology
Publisher	Data powered by TypesetAmerican Scientific Publishers
ISSN	1533-4880
Open Access	0