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.

John Kennedy L

Physics

School of Advanced Sciences

Chennai Campus

Sundararajan M

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 Environmental Chemical Engineering

In the current research, ZnFe2O4, Zn0.50Cu0.50Fe2O4, ZnFe1.90Bi0.10O4, ZnFe1.95Ce0.05O4, Zn0.50Cu0.50Fe1.90Bi0.10O4 and Zn0.50Cu0.50Fe1.95Ce0.05O4 magnetic nanoparticles were synthesized to remove the BPA (bisphenol A) from contaminated water through photocatalytic performance. The synthesized nanoparticles were characterized by powder XRD, UV-DRS, FT-IR, SEM-EDAX, VSM and XPS. From the XRD results it was observed that the particle size ranged from 38.26 to 30.18 nm. UV-DRS showed the band gap value ranging from 1.94 to 1.04 eV for the fabricated magnetic nanoparticles. Under 250 W UV-light irradiation, degradation of BPA using Zn0.50Cu0.50Fe1.90Bi0.10O4 and Zn0.50Cu0.50Fe1.95Ce0.05O4 nanoparticles were 90.09 and 91.25% in 180 min with the rate constant of (k) 0.02250 and 0.02365 min−1, respectively. The reactive species responsible for photocatalytic degradation were hydroxy radicals and superoxide radicals. 87.89% and 88.91% of degradation was observed after three cycles using Zn0.50Cu0.50Fe1.90Bi0.10O4 and Zn0.50Cu0.50Fe1.95Ce0.05O4 nanoparticles. The outcomes indicated that Zn0.50Cu0.50Fe1.90Bi0.10O4 and Zn0.50Cu0.50Fe1.95Ce0.05O4 nanoparticles show good stability for BPA degradation. © 2019 Taiwan Institute of Chemical Engineers

Journal of the Taiwan Institute of Chemical Engineers

Effect of co-doping of bismuth, copper and cerium in zinc ferrite on the photocatalytic degradation of bisphenol A

A rapid synthetic technique is investigated for magnetic nanoparticles (Co1−yCuyFe2−xCexO4 (x = 0, y = 0), (x = 0.05, y = 0), (x = 0, y = 0.5), and (x = 0.05, y = 0.5)). The structure, morphology, optical and magnetic performance of prepared nanoparticles are analyzed by powder XRD, XPS, FT-IR, SEM-EDAX, TEM, DRS, and VSM. The photocatalytic activity of the synthesized nanoparticles for the removal of the Congo red (CR) dye and bisphenol A (BPA) from aqueous solution is examined by UV–visible spectrometer. Research indicates that the co-doping of Cu2+ and Ce3+ showed marked effect on the structural, optical, magnetic, and photocatalytic properties of the CoFe2O4 nanoparticles. DRS showed that the Co0.5Cu0.5Fe1.95Ce0.05O4 nanoparticles have lower band gap energy (0.78 eV) than other synthesized compounds. High removal percentage of CR and BPA (99.09% and 99.33%) was observed within 30 min and 180 min under visible and UV–light illumination respectively using Co0.5Cu0.5Fe1.95Ce0.05O4. The corresponding photocatalytic degradation kinetics and mechanism are analyzed. © 2019, Springer-Verlag GmbH Germany, part of Springer Nature.

Environmental Science and Pollution Research

Copper and cerium co-doped cobalt ferrite nanoparticles: structural, morphological, optical, magnetic, and photocatalytic properties

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

Cerium-doped copper aluminate (CuAl2- xCexO4, x = 0, 0.01, 0.03, and 0.05) photo-catalysts were synthesized by combustion route with an aim to improve the photocatalytic activity of copper aluminate under visible-light. The synthesized compounds were analyzed by standard analytical instruments such as powder XRD, FT-IR, UV-DRS, SEM-EDAX, and HR-TEM. XRD results explained that rising cerium ion concentration from 0 to 0.03, increase the lattice parameter and decreases the average crystalline size. The band gap energy of copper aluminate (1.81 eV) was reduced to 1.43 eV by introducing the cerium ion. The photodegradation performance of the synthesized compounds was recorded by studying the degradation of organic pollutants such as Rhodamine B and Methylene blue dyes under visible light. Cerium doped copper aluminate (x = 0.03) nanoparticles shows 98% degradation of RhB and 96% degradation of MB after 180 and 90 min than the doped (x = 0.01, 0.05) and undoped copper aluminate (x = 0) nanoparticles, respectively. The reactive species h+ and ·O2 ‒ plays the most important role in the photocatalytic degradation. The photodegradation of colorless pollutant Bisphenol A was carried out under UV-light. Among the series of synthesized compounds, CuAl1.97Ce0.03O4 nanoparticles were found to be the more active photo-catalyst for the degradation of Rhodamine B and Methylene blue. © 2018 Taiwan Institute of Chemical Engineers

Photocatalytic performance of cerium doped copper aluminate nanoparticles under visible light irradiation

Structural, optical and electrical properties of ZnO-ZnS nanocomposites prepared by simple hydrothermal method

Nanostructured Co1-xZnxFe2O4 (0≤x≤0.5) catalyst synthesized by the microwave combustion method was employed for the photocatalytic degradation of rhodamine B (RhB) under visible light. Doping of Zn2+ ions in the cobalt ferrite matrices were confirmed by the diffraction peak-shift towards lower angles. The Williamson-Hall method was used to calculate the crystallite size considering the strain components. The conduction band (CB) and valence band (VB) edges of all the samples were calculated using optical studies. Photoluminescence analysis performed at an excitation wavelength of 330 nm disclosed the rate of recombination of electron-hole pairs and the defects present. Photocatalytic degradation of RhB with pure cobalt ferrite system was performed at pH 2.0 by varying the time, initial concentration and addition of hydrogen peroxide to behave like a Fenton like process. However the effective photodegradation of all zinc doped cobalt ferrite were done at optimal RhB concentration of 6 mg/l at identical operational conditions. Among all the samples Co0.6Zn0.4Fe2O4 exhibited an enhanced degradation efficiency of 99.9% at visible light exposure time of 210 min. The degradation pathway followed first order rate rather than the second order rate kinetics. Based on the values of CB and VB edges in the Co0.6Zn0.4Fe2O4 system, possible routes for the degradation of RhB are suggested. © 2016 Elsevier Ltd and Techna Group S.r.l.

Ceramics International

Photocatalytic degradation of rhodamine B under visible light using nanostructured zinc doped cobalt ferrite: Kinetics and mechanism

The present work describes the successful synthesize of spinel magnetic ferrite Mn1-xNixFe2O4 (x = 0.0, 0.1, 0.2, 0.3, 0.4 &amp; 0.5) nanoparticles via a simple microwave combustion method which was then evaluated for its photocatalytic activity in the degradation of indigo carmine (IC) synthetic dye, a major water pollutant. Our results reveal that the synthesized of Ni2+ doped MnFe2O4 nanoparticles possess well-crystalline pure cubic spinel phase, exhibit excellent optical and magnetic properties. Further, the photocatalytic performance of the synthesized nanoparticles at different concentration ratios of Ni2+ ions was monitored by photocatalytic degradation of indigo carmine synthetic dye under UV (λ = 365 nm) light irradiation. In order to get maximum photocatalytic degradation (PCD) efficiency, we have optimized various parameters, which include catalyst dosage, initial dye concentration, pH and Ni2+ dopant content. It was found that the reaction was facilitated with optimum catalyst dose of 50 mg/100 mL, high dye concentrations of 150 mg/L and acidic pH and among all the synthesized samples, Mn0·5Ni0.5Fe2O4 exhibit superior performance of photocatalytic activity on the degradation of indigo carmine synthetic dye. These results highlighted the potential use of effective, low-cost and easily available photocatalysts for the promotion of wastewater treatment and environmental remediation. In addition, the antibacterial activity of spinel magnetic Mn1–xNixFe2O4 nanoparticles against two Gram positive bacteria (Staphylococcus aureus and Bacillus subtilis) and two Gram negative bacteria (Pseudomonas aeruginosa and Escherichia coli) was also examined. Our antibacterial activity results are comparable with the results obtained using the antibiotic, streptomycin. © 2016 Elsevier B.V.

Journal of Photochemistry and Photobiology B: Biology

Studies on the efficient dual performance of Mn1–xNixFe2O4 spinel nanoparticles in photodegradation and antibacterial activity

Nanostructured pure and zinc doped cobalt ferrites (Co1-xZnxFe2O4 where x fraction ranging from 0 to 0.5) were prepared by microwave combustion method employing urea as a fuel. The nanostructured samples were characterized by using various instrumental techniques such as X-ray powder diffractometry, high resolution scanning electron microscopy, energy dispersive X-ray analysis, UV-visible diffuse reflectance spectroscopy, photoluminescence spectroscopy and Fourier transformed infrared (FT-IR) spectroscopy. Vibrating sample magnetometry at room temperature was recorded to study the magnetic behavior of the samples. X-ray analysis and the FT-IR spectroscopy revealed the formation of cobalt ferrite cubic spinel-type structure. The average crystallite sizes for the samples were in the range of 3.07-11.30 nm. The direct band gap (Eg) was estimated using Kubelka-Munk method and is obtained from the UV-vis spectra. The band gap value decreased with an increase in zinc fraction (2.56-2.17 eV). The violet and green emission observed in the photoluminescence spectra revealed that cobalt ferrites are governed by defect controlled processes. The elemental analysis of zinc doped cobalt ferrites were obtained from energy dispersive X-ray (EDX) analysis. From the magnetic measurements, it is observed that cobalt ferrite and zinc doped cobalt ferrite systems fall under the soft ferrite category. The saturation magnetization (Ms) value of undoped cobalt ferrite is 14.26 emu/g, and it has reached a maximum of 29.61 emu/g for Co0.7Zn0.3Fe2O4. © 2014 Elsevier B.V. All rights reserved.

Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy

Microwave combustion synthesis of Co1−xZnxFe2O4 (0⩽x⩽0.5): Structural, magnetic, optical and vibrational spectroscopic studies

Zn1-xNixAl2O4 (0 ≤ x ≤ 0.5) spinel nanostructures were synthesized by microwave combustion technique. Structural, vibrational, optical, morphological and magnetic properties were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), diffuse reflectance (DRS) and photoluminescence (PL) spectroscopy, high resolution scanning electron microscopy (HR-SEM), and vibrating sample magnetometry (VSM), respectively. The XRD pattern confirmed the formation of a single phase cubic spinel structure of ZnAl2O4 (gahnite), except for higher dopant concentrations for which a secondary phase was observed and validated by Rietveld refinement analysis. Different concentration levels of Ni2+ was used as the dopant in the zinc aluminate matrix. Decrease in lattice parameter and increase in porosity were observed on increasing Ni3+ concentration. The average crystallite size of the nanoparticles estimated using Debey-Scherrer's method was found to be in the range of 8.89-13.84 nm. The William-Hall (W-H) analysis was used to study the effects of lattice strain over the crystallite size. FT-IR spectra showed the vibrational stretching frequencies corresponding to the zinc aluminate spinels. The optical band gap value of undoped zinc aluminate nanostructure is higher than the reported bulk zinc aluminate. The direct band gap estimated using the Kubelka-Munk method decreased with increasing Ni2+ content (5.05-3.98 eV), due to the formation of subbands in the energy gap. The HR-SEM images depict the formation of well developed nano-sized clusters with homogeneous well crystallized grains without any agglomerations. The PL characteristics of undoped and Ni2+ doped zinc aluminates are suggestive of defect controlled process. Magnetic measurements revealed that the undoped ZnAl2O4 has diamagnetic behavior while the Ni2+ doped ZnAl2O4 system has superparamagnetic behavior, despite NiO impurities. © 2014 Elsevier Ltd and Techna Group S.r.l. All rights reserved.

Structural, optical and magnetic characterization of Zn1−xNixAl2O4 (0≤x≤5) spinel nanostructures synthesized by microwave combustion technique

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.

Journal of Nanoscience and Nanotechnology

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

Journal	Data powered by TypesetJournal of Environmental Chemical Engineering
Publisher	Data powered by TypesetElsevier BV
ISSN	2213-3437
Open Access	0