Nanocrystalline ZnFe2O4 samples were synthesized by both conventional combustion method (CCM) and microwave assisted combustion method (MCM) using Hibiscus rosa-sinensis plant extract for comparison purpose. The prepared ZnFe2O4 samples were characterized by X-ray diffraction (XRD), Rietveld analysis, Fourier transform-infrared spectrophotometer (FT-IR), high resolution scanning electron microscopy (HR-SEM), energy dispersive X-ray analysis (EDX), diffuse reflectance spectroscopy (DRS), photoluminescence (PL) spectroscopy, and vibrating sample magnetometer (VSM). The formation of single phase ZnFe2O4 was confirmed by XRD and FT-IR. The lattice parameter was calculated by Rietveld analysis. The change in the particle size ranges from 372.0 to 541.7 nm and 23.4 to 48.5 nm respectively for the conventional and microwave methods and has been clearly shown by HRSEM. UV-visible diffuse reflectance spectroscopy is used to measure the band gaps of ZnFe2O4, which is about 2.1 eV. Single phase ZnFe2O4 emits the photoluminescence bands at 486, 530, 542, and 566 nm. The magnetic properties of the synthesized ZnFe2O4 nanoparticles were investigated by VSM studies and the hysteresis loops were studied at room temperature. The saturation magnetization (Ms) of ZnFe2O4-CCM (63.61 emu/g) is lesser than that of ZnFe2O4-MCM (255.7 emu/g). ZnFe2O4 nanoparticles prepared by the microwave assisted combustion method were found to have higher surface area and lower crystallite size than ZnFe2O4 nanoparticles prepared by the conventional combustion method. © 2015 Elsevier Ltd and Techna Group S.r.l. All rights reserved.

John Kennedy L

Physics

School of Advanced Sciences

Chennai Campus

Kombaiah K

Vijaya J.J

Bououdina 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

Ceramics International

A simple and rapid synthesis has been developed to synthesize NiFe2O4 nanoparticles with tunable optical, magnetic and catalytic properties by using Hibiscus rosa sinensis plant extract in the current study. The crystalline structure of the synthesized NiFe2O4 nanoparticles was confirmed by X-Ray diffraction (XRD) and Rietveld refinement analysis. Morphological, elemental, magnetic and optical properties of the synthesized nanoparticles were interpreted by fourier transform infra-red spectroscopy (FTIR), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX), UV–Visible diffused reflectance spectroscopy (UV-DRS), photoluminescence (PL) studies, and vibrating sample magnetometer (VSM). XRD analysis showed the single phase crystalline nature with average crystallite size of 50–70 nm. SEM and EDX analysis recognize the spherical shape nanoparticles and phase purity of the samples. The optical band gap is determined using UV-DRS spectra and is observed to decrease with increasing the calcination temperature. VSM studies obviously demonstrate the ferromagnetic property of the samples. The value of saturation magnetization has decreased with an increase in the calcination temperature and the coercivity is decreased. Additionally, NiFe2O4 nanoparticles were investigated for the catalytic reduction capability for different dyes like Rhodamine-B (Rh-B), Methylene blue (MB), Rose Bengal (RB), and Congo red (CR). It is found that the dye solution was degraded with increasing irradiation time. Hence, the prepared nanoparticles have been used as high potential catalysts for the reduction of organic dyes in the application of waste water treatment. NiFe2O4 is an active agent in catalyzing the oxidation of glycerol to formic acid with good conversion percentage and high selectivity. This catalytic system in the polar solvents, such as, acetonitrile provides the enhanced conversion results. The very important role played by a variety of reaction parameters in deciding the catalytic effectiveness is well established and every parameter has an optimal value to acquire the maximum catalytic activity. © 2018 Elsevier B.V.

Materials Chemistry and Physics

Catalytic studies of NiFe2O4 nanoparticles prepared by conventional and microwave combustion method

Zinc ferrite (ZnFe2O4) magnetic nanoparticles (NPs) were important due to their biological applications. In this work, zinc ferrite nanoparticles were synthesised by green method using Aegle marmelos leaves extract antimicrobial activity and drug delivery were studied. The synthesized magnetic nanoparticles were characterized by powder x-ray diffraction method (XRD), Fourier transform infrared spectroscopy (FTIR), vibrating sample magnetometer (VSM) and scanning electron microscopy (FE-SEM). XRD pattern of the synthesised ferrite samples showed cubic structure and matched with JCPDS no: 82-1042. FTIR spectroscopy revealed the characteristic functional group of ferrite nanoparticles. Magnetic properties of synthesised ferrite nanoparticles were studied using VSM. Agglomerated and irregular shaped particles were noticed from SEM. The synthesized ZnFe2O4 nanoparticles released 95% of carfilzomib (cancer drug) drug in 360 min. Furthermore, antibacterial activity was studied by well diffusion method against Escherichia coli (17 nm), Pseudomonas aeruginosa (25 nm), and Staphylococcus aureus (22 nm) and Bacillus subtilis (23 nm). Higher zone of inhibition was noted against pseudomonas aeruginosa compared to other organisms. © 2018 IOP Publishing Ltd.

Materials Research Express

Aegle marmelos leaves extract mediated synthesis of zinc ferrite: Antibacterial activity and drug delivery

Nanosized copper ferrite (CuFe2O4) nanoparticles have been prepared by conventional (CCM) and microwave (MCM) combustion methods using Hibiscus rosa sinensis plant extract as a fuel. XRD and rietveld analysis confirmed the formation of single cubic phase and with crystallite size varying from 25 to 62 nm owing to grain growth after calcination. FT-IR analysis confirms the modes of the cubic CuFe2O4 phase, due to the stretching and bending vibrations. Spherical shaped particles are observed by scanning electron microscopy and the average particle size is found to be in the range of 50–200 nm. The chemical composition is confirmed by energy dispersive X-ray analysis. The optical band gap energy estimated using Kubelka-Munk function with the help of UV–Visible diffused reflectance spectroscopy, is found to be 2.34 and 2.22 eV for CCM and MCM respectively. Photoluminescence analysis indicates that both samples absorb light in the UV–visible region and exhibit emissions at 360, 376, and 412 nm. Magnetic measurements indicate a ferromagnetic behavior, where both magnetic properties very much influenced by the preparation method and calcination temperature: both saturation magnetization and coercivity are found higher when using CCM and MCM; from 29.40 to 34.09 emu/g while almost double from 224.4 to 432.2 Oe. The observed changes in physical properties are mainly associated with crystallinity, particle size, better chemical homogeneity, and cations distribution among tetrahedral/octahedral sites. The maximum specific absorption rate obtained was 14.63 W/g, which can be considered suitable and favorable for magnetic hyperthermia. This study highlighted the benefits of green synthesis of CuFe2O4 nanoparticles providing better magnetic properties for the platform of hyperthermia application. © 2017 Elsevier Ltd

Journal of Physics and Chemistry of Solids

Conventional and microwave combustion synthesis of optomagnetic CuFe2O4 nanoparticles for hyperthermia studies

In the present study, we have focused on opuntia dilenii haw mediated green synthesis of cobalt ferrite (CoFe2O4) nanoparticles through microwave combustion method (MCM) and it is further compared with the conventional combustion method (CCM). The effect on structural, morphological, optical and magnetic properties of the synthesized nanoparticles was investigated systematically. In addition, the efficiency of self heating measurements was investigated for hyperthermia applications. X-ray diffraction studies confirmed the formation of single phase crystalline nature of CoFe2O4 nanoparticles. The crystallite size of 58 nm and 49 nm is obtained for CCM and MCM respectively. The functional groups occurred at 597 cm−1, 599 cm−1, 427 cm−1 and 437 cm−1 that corresponds to Fe-O and Co-O bands at tetrahedral and octahedral sites are analyzed by FT-IR studies. Scanning electron microscopy images of the samples revealed the morphology as spherical with the average particle size range of 40–200 nm. The existence of Co, Fe, O present in the sample is confirmed by EDX analysis which shows the purity of the samples. UV–Visible diffuse reflectance spectroscopy is used to analyze the optical band gap energy of the samples estimated from Kubelka-Munk function as 2.01 eV, 1.93 eV for CCM and MCM respectively. The structural defects present in the samples are investigated by photoluminescence studies and the samples emit the light at two different wavelengths of 494 nm, and 621 nm. Vibrating sample magnetometer is carried out to analyze the magnetic properties of the samples at room temperature. The saturation magnetization of the CoFe2O4 nanoparticles is found to be 77.29 emu/g and 68.76 emu/g for MCM and CCM respectively. The results obtained in this work suggested that the value of crystallite size, particle size, band gap value, luminescence intensities, and coercivity values increases with an increase in calcination temperature in conventional combustion method. Specific absorption rate (SAR) increases with a decrease in the crystallite size and particle size in microwave combustion method. The gradual increase in SAR is due to the hysteresis loss that occurs because of the ferromagnetic nature obtained by the microwave combustion method. An overview of the present work gives a summary on the green synthesis of magnetic nanoparticles, which provides comprehensive evaluation of hyperthermia through self heating process. Finally, from our results, the SAR obtained by microwave combustion method has higher efficiency compared to the conventional combustion method. © 2017 Elsevier B.V.

Journal of Alloys and Compounds

Self heating efficiency of CoFe2O4 nanoparticles: A comparative investigation on the conventional and microwave combustion method

Herein, we report a sustainable production of magnetic cobalt ferrite nanoparticles by conventional (CHM) and microwave heating (MHM) method. Hibiscus rosa-sinensis extract was used as both reducing and stabilizing agent. Using plant extracts to synthesize nanoparticles has been considered as an eco-friendly method, since it avoids noxious chemicals. The plethora of plant extract mediated nanoparticles were compared by techniques, such as XRD, Rietveld, FT-IR, SEM, EDX, UV-Visible DRS, PL and VSM were carried out to analyze and understand their crystallite size, functional groups, morphology, optical and magnetic properties. The crystalline structure of cobalt ferrite nanoparticles revealed the cubic structure and the microwave heating of nanoparticles showed smaller crystallite size compared to the conventional heating, which was then confirmed by XRD analysis. To analyze the presence of functional groups and the phytochemical involvement of the plant extract was confirmed by FT-IR studies. Spherical morphology with less than 100 nm sized particles was confirmed by SEM and EDX analysis confirm the existence of Co, O, and Fe elements present in the samples. UV-Visible DRS studies were carried out to calculate the band gap of the as-synthesized nanoparticles, estimated from the Kubelka-Munk function, as 2.06, and 1.87 eV for CHM and MHM, respectively. Photoluminescence emission spectrum of the nanoparticles showed two different bands at 494 and 620 nm, which explores the optical properties of the nanoparticles, due to the quantum confinement effect. VSM analysis showed better ferromagnetic behavior, which can be used for magnetic applications. © 2017 Elsevier Ltd and Techna Group S.r.l.

Comparative investigation on the structural, morphological, optical, and magnetic properties of CoFe2O4 nanoparticles

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

Highly ordered CoFe2O4 nanowires array prepared via a modified sol–gel templated approach and its optical and magnetic properties

International Journal of Hydrogen Energy

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

Applied Surface Science

Quantum size effect on ZnO nanoparticle-based discs synthesized by mechanical milling

Low temperature hydrothermal synthesis and characterization of Mn doped cobalt ferrite nanoparticles

Studies on the microwave assisted and conventional combustion synthesis of Hibiscus rosa-sinensis plant extract based ZnFe2O4 nanoparticles and their optical and magnetic properties

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ISSN	0272-8842
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