Zinc doped cobalt ferrite spinel nanoparticles were prepared by the microwave combustion method. All the samples were characterized by using X-ray diffraction technique (XRD), Scanning Electron Microscopy, energy dispersive X-ray analysis, UV-visible diffuse reflectance spectroscopy, Fourier transformed infrared (FT-IR) spectroscopy and vibrating sample magnetometry. The XRD patterns confirmed the formation of single phase CoFe2O4 inverse spinel structure without impurities. The lattice parameter increased from 8.380 to 8.396 Å with increasing Zn2+ fraction. The average crystallite sizes obtained by a Scherrer method varied between 46.22 nm and 30.79 nm. The estimated band gap energy values increases with an increasing zinc fraction (1.88-2.10 eV). The elemental composition of Zn, Co, and Fe was qualitatively obtained from energy dispersive X-ray (EDX) analysis. © 2015 Elsevier Ltd.

John Kennedy L

Physics

School of Advanced Sciences

Chennai Campus

Sundararajan M

Aruldoss U

Pasha S.K

Vijaya J.J

Dunn S.

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

Materials Science in Semiconductor Processing

Pure and manganese doped zinc ferrite nanoparticles were prepared via sonication assisted microwave irradiation method and it's employed for biodiesel production from used cooking oil (UCO). The nanoparticles were characterized by XRD, FTIR, DRS, HR-SEM, EDX and VSM techniques. The X-ray diffraction (XRD) results confirmed the formation of cubic spinel structure with Fd-3m space group without any impurities. The average crystalline size of manganese doped and undoped zinc ferrites were in the range from 7.49 nm to 9.65 nm as calculated from Scherer's formula. Fourier transformed infrared spectroscopy (FTIR) studies show the characteristic bands at 550 cm−1 and 419 cm−1 which confirming the presence of Fe-O and Zn-O vibrational stretching frequencies related to octahedral and tetrahedral positions of the zinc ferrite spinel's. UV–vis diffuse reflectance spectroscopy (DRS) revealed the optical energy band gap values in the range 1.90 eV–1.99 eV. The magnetic parameter such as coercivity (Hc), remanence magnetization (Mr) and saturation magnetization (Ms) were determined from hysteresis curves recorded at room temperature. The prepared ferrite nanoparticles were employed for the production of biodiesel from used cooking oil by transesterification process. The maximum yield of biodiesel 98.3% was achieved with 4 wt% of Mn2+ doped ZnFe2O4 nanocatalyst (ZnMnF5), reaction time 50 min, reaction temperature about 65 °C and methanol to oil molar ratio of 21:1. The ZnMnF5 sample was reused atleast 10 times with less reduction in activity. The standard values of biodiesel was measured using ASTM D-6751 method. The formation and composition of fatty acid methyl esters (FAME) were conformed using Gas chromatography-Mass spectroscopy. Mechanism for the biodiesel production using the doped zinc ferrite nanoparticle was proposed. © 2018 Elsevier B.V.

Journal of Alloys and Compounds

Structural, optical and magnetic properties of Zn1-xMnxFe2O4 (0 ≤ x ≤ 0.5) spinel nano particles for transesterification of used cooking oil

Journal of Nanoscience and Nanotechnology

Catalytic Conversion of Methanol to Formaldehyde Over La2CuO4 Nanoparticles

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

Strontium doped lanthanum cuprate perovskite-type nanostructures were synthesized by facile microwave assisted combustion method. The structural, optical, morphological, and magnetic properties were studied by using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), diffuse reflectance spectroscopy (DRS), scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX), photoluminescence (PL) and vibrating sample magnetometer (VSM) techniques.The XRD patterns of pure La2CuO4 (LC) and La1.9Sr0.1CuO4 confirmed the formation of perovskite structure without impurities. However with the increase in Sr2+ content from (x = 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 39.6–47.4 nm and 22.3–88.0 nm, respectively. The presence of tensile strain in Sr2+ doped LC (LSC) was determined from Williamson–Hall (W–H) analysis. The appearance of FT-IR bands at around 688 and 521 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 increased with increasing Sr2+ content (1.88–2.03 eV), due to quantum confinement. For LC and LSC, PL spectra showed emission bands in UV and visible regions, due to the defect centers acting as trap levels. The LSC system showed the formation of nanosized crystallized grains with pores and pore-walls due to fused grains. Magnetization–Field (M−H) hysteresis curves revealed the appearance of ferro-/para- magnetic behavior at room temperature. © 2018 Elsevier B.V.

Journal of Magnetism and Magnetic Materials

Facile microwave assisted combustion synthesis, structural, optical and magnetic properties of La2−Sr CuO4 (0 ≤ x ≤ 0.5) perovskite nanostructures

In this study, cobalt ferrite and bismuth substituted cobalt ferrite (CoFe2−xBixO4 x=0, 0.1) nanoparticles were synthesized by two different methods viz combustion and co-precipitation. The nanoparticles were characterized by powder X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), diffuse reflectance spectroscopy (DRS), scanning electron microscopy-energy dispersive X-ray analyzer (SEM-EDX) and vibrating sample magnetometer (VSM). The results of powder XRD pattern showed an increase in lattice parameter and decrease in particle size of cobalt ferrite by the substitution of bismuth. Catalytic activity of cobalt ferrite and bismuth substituted cobalt ferrite nanoparticles synthesized by two different methods were compared for the reduction of 4-nitrophenol to 4-aminophenol using NaBH4 as a reducing agent. © 2016 Elsevier B.V.

Comparison of catalytic activity of bismuth substituted cobalt ferrite nanoparticles synthesized by combustion and co-precipitation method

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.

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

Diyala Journal For Pure Science

Preparation of M-type Barium Hexaferrite and Studying Structural and Microwave Properties

Journal of Molecular Structure

Synthesis, structural and magnetic behavior studies of Zn–Al substituted cobalt ferrite nanoparticles

Effect of Cu2+ doping on structural, morphological, optical and magnetic properties of MnFe2O4 particles/sheets/flakes-like nanostructures

Magnetic and structural properties of nano sized Dy-doped cobalt ferrite synthesized by co-precipitation

Microwave combustion synthesis of zinc substituted nanocrystalline spinel cobalt ferrite: Structural and magnetic studies

Journal	Data powered by TypesetMaterials Science in Semiconductor Processing
Publisher	Data powered by TypesetElsevier BV
ISSN	1369-8001
Open Access	0