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Barathiraja C.,Khadir Mohideen College Adirampattinam | Barathiraja C.,Mannai Rajagopalaswami Government Arts College | Manikandan A.,Bharath University | Uduman Mohideen A.M.,Khadir Mohideen College Adirampattinam | And 3 more authors.
Journal of Superconductivity and Novel Magnetism | Year: 2016

Manganese doped nickel ferrite (MnxNi1−xFe2O4: x = 0.0–0.5) spinel nanoparticles (NPs) were successfully prepared by a facile microwave combustion method (MCM) using urea as the fuel. The prepared samples were characterized by different techniques. Powder X-ray diffraction (XRD) analysis was confirmed the formation of a single-phase NiFe2O4 spinel structure. The average crystallite sizes of the samples were in the range of 11.49 to 17.24 nm, which was confirmed by Sherrer’s formula. The morphology of the samples showed a nanoparticle-like structure with smaller agglomeration, which was confirmed by high-resolution scanning electron microscopy (HR-SEM). The particle size diameter ranges from 15 to 20 nm, which was confirmed by high-resolution transmission electron microscopy (HR-TEM). Energy dispersive X-ray (EDX) analysis confirmed the elemental composition, which was also evidence for the formation of single pure phase. Selected area electron diffraction (SAED) analysis showed well crystalline nature. UV-visible diffuse reflectance spectra (DRS) and photoluminescence (PL) spectrum analysis was used to calculate the optical band gap, and the values are slightly increased (2.02 to 2.42 eV) with increasing the Mn-dopant, due to the decreasing of particle size, which may be due to the quantum confinement effect. Magnetic properties of the samples were analyzed by vibrating sample magnetometer (VSM) technique, which showed the magnetization (Ms) value of the samples are increased with increasing Mn content and reach a maximum value of 67.82 emu/g for Mn0.5Ni0.5Fe2O4 sample. Photo-catalytic activity of the samples was measured and showed the photocatalytic degradation (PCD) of methylene blue dye with good results. The catalyst was magnetically recycled and reused five consecutive cycles and showed good reproducibility without change of catalytic activity. © 2015, Springer Science+Business Media New York.


Jayasree S.,Kunthavai Naacchiyaar Government Arts College for Women Autonomous | Jayasree S.,Khadir Mohideen College | Manikandan A.,Bharath University | Antony S.A.,Presidency College at Chennai | And 2 more authors.
Journal of Superconductivity and Novel Magnetism | Year: 2015

Spinel nickel aluminate (NiAl 2O4) nanospheres (NSPs) and nanoplatelets (NPLs) were successfully synthesized using a facile microwave combustion method (MCM) and conventional combustion method (CCM), respectively, using urea as the fuel. The as-prepared samples were characterized by powder X-ray diffraction (XRD), Fourier transform infrared (FT-IR), high-resolution scanning electron microscopy (HR-SEM), high-resolution transmission electron microscopy (HR-TEM), energy-dispersive X-ray spectroscopy (EDX), selected area electron diffraction (SAED), UV–Visible diffuse reflectance spectroscopy (DRS), photoluminescence (PL) spectroscopy, and vibrating sample magnetometer (VSM) analysis. Powder XRD, FT-IR, EDX, and SAED results showed that the samples were pure phase spinel NiAl 2O4 nanocrystals without any other secondary phase impurity. UV–Vis DRS and PL spectroscopy results were used to calculate the energy band gap (Eg) value of the samples which is 3.41 and 3.08 eV for NiAl 2O4 NSPs and NiAl 2O4 NPLs, respectively. VSM results of the NiAl 2O4 NPLs sample show lower Ms (49.16 × 10 −3 emu/g) values compared with the NiAl 2O4 NSPs sample (73.42 × 10 −3 emu/g), which confirm that both the products have ferromagnetic behavior. NiAl 2O4 NSPs were found to have higher surface area than NiAl 2O4 NPLs, which in turn leads to the improved performance towards the selective oxidation of benzyl alcohol into benzaldehyde, with 100 % selectivity, and it was found that the NiAl 2O4 NSPs sample show higher conversion (96.25 %) than NiAl 2O4 NPLs (85.37 %). The as-prepared samples show high activity, good reusability, remarkable stability, and environmentally friendly materials for industrial and technological applications. [Figure not available: see fulltext.] © 2015 Springer Science+Business Media New York


Manikandan A.,Presidency College at Chennai | Hema E.,Kunthavai Naacchiyaar Government Arts College for Women Autonomous | Durka M.,AVVM Sri Pushpam College Autonomous | Amutha Selvi M.,Avinashilingam University For Women | And 2 more authors.
Journal of Inorganic and Organometallic Polymers and Materials | Year: 2015

To reduce the synthesis time, energy consumption, low cost, Mn2+-doped NiS (MnxNi1−xS: x = 0.0, 0.3 and 0.5) nano-photocatalysts were successfully synthesized by a facile, one-pot, microwave combustion method (MCM) within 10 min. In this MCM route, microwave heating has produced such functional nano-photocatalysts within few minutes of time. Powder XRD, FT-IR, EDX and SAED results were confirmed the formation of well crystalline single phase of NiS nano-crystals. The as-prepared samples consist of agglomerated particles with nano-crystals like morphologies confirmed by HR-SEM and HR-TEM analysis. The optical band gap energy (Eg) was estimated from UV–Vis DRS and PL study. The value of Eg is increased with increasing Mn doping in MnxNi1−xS lattice, due to decrease of particle size. VSM results confirmed a weak ferromagnetic behavior of MnxNi1−xS nano-crystals and the values of magnetization (Ms) gradually increased with increasing the concentration of Mn2+ cations, due to the higher magnetic moment (5 μB) of Mn2+ ions replaced the lower magnetic moment (2 μB) of Ni2+ ions in NiS. The present study leads to enhance the photocatalytic activity of MnxNi1−xS samples, TiO2 catalyst was added. As expected, MnxNi1−xS nanoparticles sensitized TiO2 catalyst showed enhanced photocatalytic degradation (PCD) of 4-chlorophenol (4-CP) under visible light irradiation. The alteration of MnxNi1−xS–TiO2 nano-composite catalysts shows higher adsorption with synergistic effect and enhances the separation of photogenerated electron–hole pairs, important to higher PCD efficiency. © 2015, Springer Science+Business Media New York.


Manikandan A.,Presidency College at Chennai | Hema E.,Kunthavai Naacchiyaar Government Arts College for Women Autonomous | Durka M.,AVVM Sri Pushpam College Autonomous | Seevakan K.,Presidency College at Chennai | And 2 more authors.
Journal of Superconductivity and Novel Magnetism | Year: 2015

Magnetically recyclable spinel Cu1−xMnxFe2O4 (0.0 ≤ x ≤ 0.5) ferrite nanophotocatalysts were synthesized by a simple one-pot microwave combustion method using glycine as the fuel. The synthesis process only took a few minutes to obtain CuFe2O4 nanopowders. The formation of nanocrystalline single-phase cubic spinel structure was confirmed by powder X-ray diffraction (XRD), Fourier transform infrared (FT-IR), energy dispersive X-ray (EDX) and selected area electron diffraction pattern (SAED) analyses. The surface morphology of the samples consists of nearly spherical shaped nanoparticles (NPs) with agglomeration, which was confirmed by high-resolution scanning electron microscopy (HR-SEM) and high resolution transmission electron microscope (HR-TEM) analyses. The optical band gap energy (Eg) was confirmed by UV-Vis diffuse reflectance spectrum (DRS) study, and the Eg of undoped CuFe2O4 sample is 2.39 eV and it is increased from 2.51–2.81 eV with increasing the amount of Mn2+ content (x = 0.1–0.5), due to the decrease of particle size. The magnetic hysteresis (M– H) curve showed ferromagnetic behavior for all compositions. The magnetization (Ms) of the samples monotonically increased with increasing Mn content x = 0.0–0.5. Smaller values of coercivity showed soft magnetic nature of Cu1−xMnxFe2O4 NPs. The photocatalytic degradation (PCD) of 4-chlorophenol (4-CP) under visible light using the spinel CuFe2O4 catalysts shows poor activity. Therefore, the present study leads to enhance the photocatalytic (PC) activity of spinel Cu1−xMnxFe2O4 NPs with the addition of TiO2 catalyst using the PCD of 4-CP under visible light. It was found that the coupled Cu1−xMnxFe2O4-TiO2 nanocomposite (NCs) photocatalysts exhibit excellent PC activity than that of Cu1−xMnxFe2O4 and TiO2 catalysts. The sample Cu0.5Mn0.5Fe2O4-TiO2 NCs showed greater performance than the other NCs. The enhanced PC ability of Cu1−xMnxFe2O4-TiO2 NCs could be ascribed to the interconnected heterojunction of spinel Cu1−xMnxFe2O4 and TiO2 catalysts. © 2015, Springer Science+Business Media New York.


Hema E.,Kunthavai Naacchiyaar Government Arts College for Women Autonomous | Manikandan A.,Presidency College at Chennai | Karthika P.,Kunthavai Naacchiyaar Government Arts College for Women Autonomous | Antony S.A.,Presidency College at Chennai | Venkatraman B.R.,Periyar EVR College Autonomous
Journal of Superconductivity and Novel Magnetism | Year: 2015

Zn2+-doped CoFe2O4 (ZnxCo1−xFe2O4: where x= 0.0, 0.2, 0.4, 0.6, 0.8, and 1.0) spinel nanoparticles (NPs) were synthesized by microwave combustion method using nitrates of cobalt, zinc, and iron as the starting materials and urea used as the fuel. Powder X-ray diffraction (XRD), Fourier transform infrared (FT-IR), energy dispersive X-ray (EDX), and selected area electron diffraction (SAED) pattern analyses showed that all composition was found to have pure cubic spinel structure with well crystalline nature. The average crystallite size of the samples was found to be in the range of 25.43 and 29.46 nm. The lattice parameter increased from 8.432 to 8.441 Å with increasing the Zn2+ content, due to the smaller ionic radius of Co2+ substituted by larger ionic radius of Zn2+, which was determined by Rietveld analysis. High-resolution scanning electron microscopy (HR-SEM) and transmission electron microscopy (HR-TEM) analyses were used to study the morphological variation, and the results showed a nano-sized spherical-shaped particle-like morphology. The band gap (Eg) of the undoped CoFe2O4 was estimated to be 2.69 eV from UV-Vis diffuse reflectance spectroscopy (DRS). With the increase of Zn2+ dopant, the Eg value decreased from 2.61 to 2.01 eV, due to the difference of particle size of the samples. The magnetic hysteresis (M−H) loop confirmed the ferromagnetic nature of undoped CoFe2O4 with magnetization (Ms) of 64.85 emu/g, and it is decreased with increasing the Zn2+ content in CoFe2O4 spinel, which was confirmed by a vibrating sample magnetometer (VSM). All composition of spinel ZnxCo1−xFe2O4 samples were successfully tested as catalyst for the conversion of benzyl alcohol, which has resulted 91.73 and 95.82 % conversion efficiency of CoFe2O4 and Zn0.4Co0.6Fe2O4 nano-catalysts, respectively. © 2015, Springer Science+Business Media New York.

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