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Journal articles on the topic 'Cofelon'

Author: Grafiati
Published: 9 March 2023
Last updated: 11 March 2023

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1

Chen, X. J., J. C. Xu, H. X. Jin, D. F. Jin, B. Hong, H. L. Ge, and X. Q. Wang. "Preparation and Characterization of Magnetic Cobalt Ferrites/SBA-15 Nanocomposite Adsorbents and the Removal of Methylene Blue." Nano 12, no. 05 (March 28, 2017): 1750060. http://dx.doi.org/10.1142/s1793292017500606.

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In this paper, ordered mesoporous SBA-15 silica was synthesized by the hydrothermal method, and then a series of CoFe2O4/SBA-15 nanocomposites were synthesized by a facile impregnation method. X-ray diffraction and N2 adsorption–desorption isotherms were used to characterize the microstructure and morphology of SBA-15 and CoFe2O4/SBA-15 nanocomposites. CoFe2O4 nanoparticles presented spinel phase structure and existed in the mesopores of SBA-15. The magnetic response of CoFe2O4/SBA-15 nanocomposites was characterized with vibrating sample magnetometer (VSM). The adsorption efficiency of CoFe2O4/SBA-15 nanocomposites for methylene blue increased firstly with the increasing CoFe2O4 content, and then decreased. Sample-2 (SBA-15: CoFe2O[Formula: see text]: 0.1 in the precursor) not only presented the best adsorptive performance, but also could be separated and retrieved effectively by magnetic separation technique.
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2

Duong, Hong Diu Thi, Dung The Nguyen, and Kyo-Seon Kim. "Effects of Process Variables on Properties of CoFe2O4 Nanoparticles Prepared by Solvothermal Process." Nanomaterials 11, no. 11 (November 13, 2021): 3056. http://dx.doi.org/10.3390/nano11113056.

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Controlling the morphology and magnetic properties of CoFe2O4 nanoparticles is crucial for the synthesis of compatible materials for different applications. CoFe2O4 nanoparticles were synthesized by a solvothermal method using cobalt nitrate, iron nitrate as precursors, and oleic acid as a surfactant. The formation of CoFe2O4 nanoparticles was systematically observed by adjusting synthesis process conditions including reaction temperature, reaction time, and oleic acid concentration. Nearly spherical, monodispersed CoFe2O4 nanoparticles were formed by changing the reaction time and reaction temperature. The oleic acid-coated CoFe2O4 nanoparticles inhibited the growth of particle size after 1 h and, therefore, the particle size of CoFe2O4 nanoparticles did not change significantly as the reaction time increased. Both without and with low oleic acid concentration, the large-sized cubic CoFe2O4 nanoparticles showing ferromagnetic behavior were synthesized, while the small-sized CoFe2O4 nanoparticles with superparamagnetic properties were obtained for the oleic acid concentration higher than 0.1 M. This study will become a basis for further research in the future to prepare the high-functional CoFe2O4 magnetic nanoparticles by a solvothermal process, which can be applied to bio-separation, biosensors, drug delivery, magnetic hyperthermia, etc.
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Suharyadi, Edi, Afifah Muzakki, Nurul Imani Istiqomah, Deska Lismawenning Puspitarum, Budi Purnama, and Dede Djuhana. "Reusability of Photocatalytic CoFe2O4@ZnO Core–Shell Nanoparticles for Dye Degradation." ECS Journal of Solid State Science and Technology 11, no. 2 (February 1, 2022): 023004. http://dx.doi.org/10.1149/2162-8777/ac4c7c.

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The reusability of CoFe2O4@ZnO core–shell nanoparticles (NPs) for the photocatalytic degradation of methylene blue (MB) under UV radiation was successfully investigated. CoFe2O4@ZnO NPs with various CoFe2O4–to–ZnO concentration ratios were synthesized as magnetic photocatalysts. The X-ray diffraction spectra showed that the NPs had a cubic spinel ferrite phase structure and a hexagonal wurtzite phase of ZnO. Fourier-transform infrared spectra showed the presence of Moct-O, Mtet-O, and Zn–O at 593, 347–389, and 410–429 cm−1, respectively. The CoFe2O4@ZnO NPs had a saturation magnetization of approximately 30 emu g−1 and a coercivity of approximately 280 Oe. The absorbance spectra showed that the absorbance peak of the CoFe2O4@ZnO NPs broadened and shifted to the right (higher wavelength) with increasing ZnO concentration. The CoFe2O4@ZnO NPs with higher ZnO concentrations exhibited higher photocatalytic activities and degradation rates. The enhancement of MB degradation can be attributed to the formation of an internal structure between CoFe2O4 and ZnO. The degradation rate of CoFe2O4@ZnO decreased slightly after each successive recycle. The results indicated that the recycled CoFe2O4@ZnO NPs could be reused three times for photocatalytic degradation. As there is no significant decrease in the photocatalytic degradation after four successive recycles, the CoFe2O4@ZnO NPs are suitable for application in dye degradation.
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Velayutham, Lakshmi, C. Parvathiraja, Dhivya Christo Anitha, K. Mahalakshmi, Mary Jenila, Fatmah Ali Alasmary, Amani Salem Almalki, Amjad Iqbal, and Wen-Cheng Lai. "Photocatalytic and Antibacterial Activity of CoFe2O4 Nanoparticles from Hibiscus rosa-sinensis Plant Extract." Nanomaterials 12, no. 20 (October 19, 2022): 3668. http://dx.doi.org/10.3390/nano12203668.

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Biogenic CoFe2O4 nanoparticles were prepared by co-precipitation and Hibiscus rosa sinensis plant leaf was used as a bio-reductant of the nanoparticle productions. The biosynthesized CoFe2O4 nanoparticles were characterized by XRD, FTIR, UV, VSM, and SEM via EDX analysis. The cubic phase of biosynthesized CoFe2O4 nanoparticles and their crystallite size was determined by XRD. The Co-Fe-O bonding and cation displacement was confirmed by FTIR spectroscopy. The presence of spherically-shaped biosynthesized CoFe2O4 nanoparticles and their material were confirmed by SEM and TEM via EDX. The super-paramagnetic behaviour of the biosynthesized CoFe2O4 nanoparticles and magnetic pulse was established by VSM analysis. Organic and bacterial pollutants were eradicated using the biosynthesized CoFe2O4 nanoparticles. The spinel ferrite biosynthesized CoFe2O4 nanoparticles generate radical and superoxide ions, which degrade toxic organic and bacterial pollutants in the environment.
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5

Masoumparast, Mehrnaz, Masoud Mokhtary, and Hassan Kefayati. "Preparation and characterization of polyvinylpyrrolidone/cobalt ferrite functionalized chitosan graphene oxide (CoFe2O4@CS@GO-PVP) nanocomposite." Journal of Polymer Engineering 40, no. 4 (April 28, 2020): 342–49. http://dx.doi.org/10.1515/polyeng-2019-0331.

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AbstractCobalt ferrite functionalized chitosan graphene oxide (CoFe2O4@CS@GO) was inserted successfully in polyvinylpyrrolidone (PVP), and its distribution was distinguished through scanning electron microscope (SEM) analysis. Furthermore, the thermal and structural characterizations of the CoFe2O4@CS@GO-PVP nanocomposite were accomplished via the TGA, DSC, FT-IR, and XRD methods. The magnetic characterization of the synthesized nanocomposite was specified by vibrating sample magnetometer (VSM). Results demonstrated the improved thermal stability of pure PVP with the addition of CoFe2O4@CS@GO. The DSC analysis results also showed that the glass transition temperature of 158.9°C–164.8°C was obtained for the CoFe2O4@CS@GO-PVP nanocomposites. The FT-IR spectra indicated that an interaction occurred between CoFe2O4@CS@GO and PVP. Due to a good distribution of CoFe2O4@CS@GO in the PVP matrix, the strong interaction shown by the ~18 cm−1 red shift with good complexation of the carbonyl functional group of PVP with CoFe2O4@CS@GO was observed for the CoFe2O4@CS@GO-PVP (5% w/w) nanocomposite.
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6

Nugroho, Kacuk Cikal, Ubaidillah Ubaidillah, Retna Arilasita, Margono Margono, Bambang Hari Priyambodo, Budi Purnama, Saiful Amri Mazlan, and Seung-Bok Choi. "The Effect of Sr-CoFe2O4 Nanoparticles with Different Particles Sized as Additives in CIP-Based Magnetorheological Fluid." Materials 14, no. 13 (July 1, 2021): 3684. http://dx.doi.org/10.3390/ma14133684.

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This study investigated the effect of adding strontium (Sr)-doped cobalt ferrite (CoFe2O4) nanoparticles in carbonyl iron particle (CIP)-based magnetorheological fluids (MRFs). Sr-CoFe2O4 nanoparticles were fabricated at different particle sizes using co-precipitation at calcination temperatures of 300 and 400 °C. Field emission scanning electron microscopy (FESEM) was used to evaluate the morphology of the Sr-CoFe2O4 nanoparticles, which were found to be spherical. The average grain sizes were 71–91 nm and 118–157 nm for nanoparticles that had been calcinated at 300 and 400 °C, respectively. As such, higher calcination temperatures were found to produce larger-sized Sr-CoFe2O4 nanoparticles. To investigate the rheological effects that Sr-CoFe2O4 nanoparticles have on CIP-based MRF, three MRF samples were prepared: (1) CIP-based MRF without nanoparticle additives (CIP-based MRF), (2) CIP-based MRF with Sr-CoFe2O4 nanoparticles calcinated at 300 °C (MRF CIP+Sr-CoFe2O4-T300), and (3) CIP-based MRF with Sr-CoFe2O4 nanoparticles calcinated at 400 °C (MRF CIP+Sr-CoFe2O4-T400). The rheological properties of these MRF samples were then observed at room temperature using a rheometer with a parallel plate at a gap of 1 mm. Dispersion stability tests were also performed to determine the sedimentation ratio of the three CIP-based MRF samples.
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7

Coldebella, E. H., E. F. Chagas, A. P. Albuquerque, R. J. Prado, M. Alzamora, and E. Baggio-Saitovitch. "Study of Soft/Hard Bimagnetic CoFe2/CoFe2O4 Nanocomposite." Journal of Nanoscience and Nanotechnology 21, no. 10 (October 1, 2021): 5181–87. http://dx.doi.org/10.1166/jnn.2021.19369.

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We report an experimental study of the bimagnetic nanocomposites CoFe2/CoFe2O4. The precursor material, CoFe2O4 was prepared using the conventional stoichiometric combustion method. The nano-structured material CoFe2/CoFe2O4 was obtained by total oxygen reduction of CoFe2O4 using a thermal treatment at 350 °C in H2 atmospheres following the partial oxidation in O2 atmospheres at 380 °C during 120; 30; 15, 10, and 5 min. The X-ray diffraction, Mössbauer spectroscopy and transmission electronic microscopy images confirmed the formation of the material CoFe2/CoFe2O4. The magnetic hysteresis for the nanocomposite with different saturation magnetization (from 87 to 108 emu/g) also confirms the formation of the CoFe2/CoFe2O4 with different content of CoFe2O4. Furthermore, the magnetic hysteresis curves for all samples presented a single magnetic behavior, suggesting the magnetic coupling between the phases of the nanocomposite. The effects of high energy milling on the magnetic properties of the precursor material and nanocomposites samples were evaluated.
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8

Cernea, Marin, Roxana Radu, Harvey Amorín, Simona Gabriela Greculeasa, Bogdan Stefan Vasile, Vasile Adrian Surdu, Paul Ganea, Roxana Trusca, Marwa Hattab, and Carmen Galassi. "Lead-Free BNT–BT0.08/CoFe2O4 Core–Shell Nanostructures with Potential Multifunctional Applications." Nanomaterials 10, no. 4 (April 3, 2020): 672. http://dx.doi.org/10.3390/nano10040672.

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Herein we report on novel multiferroic core–shell nanostructures of cobalt ferrite (CoFe2O4)–bismuth, sodium titanate doped with barium titanate (BNT–BT0.08), prepared by a two–step wet chemical procedure, using the sol–gel technique. The fraction of CoFe2O4 was varied from 1:0.5 to 1:1.5 = BNT–BT0.08/CoFe2O4 (molar ratio). X–ray diffraction confirmed the presence of both the spinel CoFe2O4 and the perovskite Bi0.5Na0.5TiO3 phases. Scanning electron microscopy analysis indicated that the diameter of the core–shell nanoparticles was between 15 and 40 nm. Transmission electron microscopy data showed two–phase composite nanostructures consisting of a BNT–BT0.08 core surrounded by a CoFe2O4 shell with an average thickness of 4–7 nm. Cole-Cole plots reveal the presence of grains and grain boundary effects in the BNT–BT0.08/CoFe2O4 composite. Moreover, the values of the dc conductivity were found to increase with the amount of CoFe2O4 semiconductive phase. Both X-ray photoelectron spectroscopy (XPS) and Mössbauer measurements have shown no change in the valence of the Fe3+, Co2+, Bi3+ and Ti4+ cations. This study provides a detailed insight into the magnetoelectric coupling of the multiferroic BNT–BT0.08/CoFe2O4 core–shell composite potentially suitable for magnetoelectric applications.
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9

Falqui, Andrea, Anna Corrias, Peng Wang, Etienne Snoeck, and Gavin Mountjoy. "A Transmission Electron Microscopy Study of CoFe2O4 Ferrite Nanoparticles in Silica Aerogel Matrix Using HREM and STEM Imaging and EDX Spectroscopy and EELS." Microscopy and Microanalysis 16, no. 2 (March 4, 2010): 200–209. http://dx.doi.org/10.1017/s1431927610000061.

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AbstractMagnetic nanocomposite materials consisting of 5 and 10 wt% CoFe2O4 nanoparticles in a silica aerogel matrix have been synthesized by the sol-gel method. For the CoFe2O4-10wt% sample, bright-field scanning transmission electron microscopy (BF STEM) and high-resolution transmission electron microscopy (HREM) images showed distinct, rounded CoFe2O4 nanoparticles, with typical diameters of roughly 8 nm. For the CoFe2O4-5wt% sample, BF STEM images and energy dispersive X-ray (EDX) measurements showed CoFe2O4 nanoparticles with diameters of roughly 3 ± 1 nm. EDX measurements indicate that all nanoparticles consist of stoichiometric CoFe2O4, and electron energy-loss spectroscopy measurements from lines crossing nanoparticles in the CoFe2O4-10wt% sample show a uniform composition within nanoparticles, with a precision of at best than ±0.5 nm in analysis position. BF STEM images obtained for the CoFe2O4-10wt% sample showed many “needle-like” nanostructures that typically have a length of ∼10 nm and a width of ∼1 nm, and frequently appear to be attached to nanoparticles. These needle-like nanostructures are observed to contain layers with interlayer spacing 0.33 ± 0.1 nm, which could be consistent with Co silicate hydroxide, a known precursor phase in these nanocomposite materials.
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10

Puspitarum, Deska Lismawenning, Nurul Imani Istiqomah, Rivaldo Marsel Tumbelaka, Ahmad Kusumaatmaja, Daiki Oshima, Takeshi Kato, and Edi Suharyadi. "High performance of magnetically separable and recyclable photocatalyst of green-synthesized CoFe2O4/TiO2 nanocomposites for degradation of methylene blue." Advances in Natural Sciences: Nanoscience and Nanotechnology 13, no. 4 (October 26, 2022): 045003. http://dx.doi.org/10.1088/2043-6262/ac996b.

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Abstract In this study, combination of ferromagnetic and semiconductor CoFe2O4/TiO2 nanocomposites was synthesised using a green synthesis method with Moringa oleifera leaf extract to easily obtain a magnetically separated nanomaterial exhibiting high photocatalytic activity. Nanocomposites with different CoFe2O4/TiO2 molar ratios were identified using x-ray diffraction (XRD), transmission electron microscopy, X-ray fluorescence, Fourier transform infrared spectroscopy, UV–visible spectroscopy, and vibration sample magnetometer. The XRD spectrum confirmed the structure of the cubic spinel ferrite and anatase phases of CoFe2O4 and TiO2, respectively. The crystallite sizes of CoFe2O4, CoFe2O4/TiO2, and CoFe2O4/3TiO2 are 7.2 nm, 8.6 nm, and 11.1 nm, respectively. The magnetic hysteresis curve showed that CoFe2O4/TiO2 had a high saturation magnetisation of 27 emu g−1 and a coercivity of 200 Oe. The optical bandgap energy for CoFe2O4/TiO2 was in the range 3.6–3.8 eV. Photocatalytic investigations were carried out using methylene blue (MB) under UV irradiation. Our results showed an increase in MB degradation with increasing TiO2 concentration. The maximum photodegradations using nanocomposites are 60.8%, 97.7%, 98.4%, 98.5%, and 98.7% at molar ratios of 1:0, 1:1, 1:2, 1:3, and 1:4, respectively, after 20 min. The increase in MB degradation was related to the formation of internal structures between CoFe2O4 and TiO2. The magnetic nanocomposites enabled separation between the photocatalyst and final degraded solution using a permanent magnet. When the degradation was above 90%, the nanocomposites could be recycled three times.
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11

Liu, Baolin, Yizhao Li, Hao Wu, Fengyun Ma, and Yali Cao. "Room-Temperature Solid-State Preparation of CoFe2O4@Coal Composites and Their Catalytic Performance in Direct Coal Liquefaction." Catalysts 10, no. 5 (May 3, 2020): 503. http://dx.doi.org/10.3390/catal10050503.

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Iron-based catalysts are promising catalysts in the direct coal liquefaction (DCL) process as they are inexpensive and environmentally friendly. However, most such iron-based catalysts show relatively low activity in coal conversion and oil yield. Common techniques for the synthesis of these catalysts with excellent catalytic performance remain a substantial challenge. We present a simple solid-state synthesis strategy for preparing CoFe2O4 nanoparticles and CoFe2O4 nanoparticles supported on coal (CoFe2O4@coal) composites for DCL. The obtained bimetallic oxide CoFe2O4 nanoparticles show an enhanced catalytic performance in the DCL compared with monometallic components Fe2O3 and Co(OH)2 nanoparticles. The synergistic effect between Co and Fe of CoFe2O4 nanoparticles promotes the catalytic hydrogenation of coal during the DCL process. Moreover, the catalytic performance of CoFe2O4 nanoparticles is further improved when they are loaded on the coal. The conversion, oil yield, liquefaction degree, and gas yield of Dahuangshan lignite are 99.44, 56.01, 82.18 and 19.30 wt %, respectively, with the CoFe2O4@coal composites involved. The smaller particle size and high dispersion of CoFe2O4 supported on coal are of great benefit to full contact between coal and active components. The in-situ solid-state synthesis with coal as support shows great potential to prepare effective iron-based catalysts toward DCL in practice.
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Hoang, Van-Tuan, Nguyen Le Nhat Trang, Dao Thi Nguyet Nga, Xuan-Dinh Ngo, Tuyet Nhung Pham, Van Tan Tran, Mai Mai, Le Thi Tam, Doan Quang Tri, and Anh-Tuan Le. "Facile synthesis and characterisations of cobalt ferrite-silver-graphene oxide nanocomposite in enhancing electrochemical response capacity." Advances in Natural Sciences: Nanoscience and Nanotechnology 13, no. 3 (July 27, 2022): 035002. http://dx.doi.org/10.1088/2043-6262/13/3/035002.

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Abstract In this report, cobalt ferrite nanoparticles (CoFe2O4 NPs) synthesised from the co-precipitation method were strongly connected with graphene oxide nanosheets (GO) via ‘bridge molecules’- polyhexamethylene biguanide hydrochloride (PHMB)’. Silver (Ag) NPs were grown on the surface of CoFe2O4-GO nanocomposites to improve the electrical conductivity and electrocatalytic ability of the proposed functional nanocomposites. Characteristics of the synthesised materials were investigated via x-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, cyclic voltammetry (CV), and differential pulse voltammetry (DPV). The obtained results demonstrate that the CoFe2O4-Ag-GO nanocomposites could significantly improve the adsorption ability and electron transfer between electrode and analytes owing to the synergetic effect of Ag NPs, CoFe2O4 NPs, and GO. The prepared CoFe2O4-Ag-GO nanocomposites showed the highest electrochemical response for chloramphenicol antibiotic detection, with current intensity response (∼24.4 μA) being 3.25 and 2.57 times higher than that of CoFe2O4 NPs (7.5 μA) and CoFe2O4-GO (9.5 μA), respectively. The calibration plot is linear in the 1–50 μM CAP concentration range, with a detection limit of 0.1 μM. With excellent electrochemical properties, the CoFe2O4-Ag-GO nanocomposites are expected to be a potential candidate for advanced electrochemical sensing applications.
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Yu, Chunpei, Wei Ren, Ganggang Wu, Wenchao Zhang, Bin Hu, Debin Ni, Zilong Zheng, Kefeng Ma, Jiahai Ye, and Chenguang Zhu. "A Facile Preparation and Energetic Characteristics of the Core/Shell CoFe2O4/Al Nanowires Thermite Film." Micromachines 11, no. 5 (May 20, 2020): 516. http://dx.doi.org/10.3390/mi11050516.

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In this study, CoFe2O4 is selected for the first time to synthesize CoFe2O4/Al nanothermite films via an integration of nano-Al with CoFe2O4 nanowires (NWs), which can be prepared through a facile hydrothermal-annealing route. The resulting nanothermite film demonstrates a homogeneous structure and an intense contact between the Al and CoFe2O4 NWs at the nanoscale. In addition, both thermal analysis and laser ignition test reveal the superb energetic performances of the prepared CoFe2O4/Al NWs nanothermite film. Within different thicknesses of nano-Al for the CoFe2O4/Al NWs nanothermite films investigated here, the maximum heat output has reached as great as 2100 J·g−1 at the optimal thickness of 400 nm for deposited Al. Moreover, the fabrication strategy for CoFe2O4/Al NWs is also easy and suitable for diverse thermite systems based upon other composite metal oxides, such as MnCo2O4 and NiCo2O4. Importantly, this method has the featured advantages of simple operation and compatibility with microsystems, both of which may further facilitate potential applications for functional energetic chips.
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Malakootian, Mohammad, Alireza Nasiri, and Mohammad Reza Heidari. "Removal of Phenol from Steel Plant Wastewater in Three Dimensional Electrochemical (TDE) Process using CoFe2O4@AC/H2O2." Zeitschrift für Physikalische Chemie 234, no. 10 (October 25, 2020): 1661–79. http://dx.doi.org/10.1515/zpch-2019-1499.

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AbstractThis study investigated the removal of phenol from steel industry wastewater by three dimensional electrochemical (TDE) process using CoFe2O4 nanobiocomposite based activated carbon in the presence of H2O2 (EC-CoFe2O4@AC-H2O2). In this study, CoFe2O4 nanobiocomposite-foundation activated carbon (CoFe2O4@AC) was used as microelectrode, adsorbent, and activator for peroxide hydrogen. The removal efficiency of phenol and COD was investigated through the parameters of pH, contact time, CoFe2O4@AC dosage, current density, and H2O2 concentration. The highest removal rates of phenol and COD were >99% and 98%, respectively. Also, steel plant wastewater under the optimal conditions of pH = 6.5, current density = 15 mA cm−2, contact time = 25 min, H2O2 concentration of 1.0 mM, and CoFe2O4@AC dose = 0.3 g L−1. Kinetic analysis revealed that the adsorption experimental data was best fitted by the pseudo-first-order model.
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Jabbar, Rihab, Awham M. Hameed, and Sabah H. Sabeeh. "The Effect of CoFe2O4 Weight Fraction on the Properties of Magnetic CoFe2O4/Unsaturated Polyester Nanocomposites Synthesized by Hand Lay-up Method." Nanoscience & Nanotechnology-Asia 10, no. 6 (November 30, 2020): 778–89. http://dx.doi.org/10.2174/2210681209666190717165106.

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Objective: In this study, Cobalt ferrite (CoFe2O4) nanopowders were prepared by the sol-gel precipitation method. Methods: The prepared ferrite powders were sintered at 1000°C for 2 hours. CoFe2O4/unsaturated polyester nanocomposites were prepared with different weight fraction of CoFe2O4. The X-ray diffraction results showed that the crystallite size (D) of CoFe2O4 was found to be 20.68 nm. Fouriertransform infrared spectroscopy (FTIR) spectra confirmed the spinal structure of CoFe2O4. Results: The saturation magnetization (Ms) and coercivity (Hc) of all the composites were found to increase with increasing ferrite content. Conclusion: Dielectric constant values were found to increase with increasing the concentration of ferrite.
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Simonescu, Claudia Maria, Alina Tătăruş, Daniela Cristina Culiţă, Nicolae Stănică, Ioana Alexandra Ionescu, Bogdan Butoi, and Ana-Maria Banici. "Comparative Study of CoFe2O4 Nanoparticles and CoFe2O4-Chitosan Composite for Congo Red and Methyl Orange Removal by Adsorption." Nanomaterials 11, no. 3 (March 12, 2021): 711. http://dx.doi.org/10.3390/nano11030711.

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(1) Background: A comparative research study to remove Congo Red (CR) and Methyl Orange (MO) from single and binary solutions by adsorption onto cobalt ferrite (CoFe2O4) and cobalt ferrite–chitosan composite (CoFe2O4-Chit) prepared by a simple coprecipitation method has been performed. (2) Methods: Structural, textural, morphology, and magnetic properties of the obtained magnetic materials were examined by X-ray diffraction (XRD), Fourier-transform infrared (FTIR) spectroscopy, N2 adsorption–desorption analysis, Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), and magnetic measurements. The optimal operating conditions of the CR and MO removal processes were established in batch experiments. The mathematical models used to describe the processes at equilibrium were Freundlich and Langmuir adsorption isotherms. (3) Results: Cobalt ferrite–chitosan composite has a lower specific surface area (SBET) and consequently a lower adsorption capacity than cobalt ferrite. CoFe2O4 and CoFe2O4–Chit particles exhibited a superparamagnetic behavior which enabled their efficient magnetic separation after the adsorption process. The research indicates that CR and MO adsorption onto prepared magnetic materials takes place as monolayer onto a homogeneous surface. According to Langmuir isotherm model that best fits the experimental data, the maximum CR/MO adsorption capacity is 162.68/94.46 mg/g for CoFe2O4 and 15.60/66.18 mg/g for CoFe2O4–Chit in single solutions. The results of the kinetics study revealed that in single-component solutions, both pseudo-first-order and pseudo-second-order kinetics models represent well the adsorption process of CR/MO on both magnetic adsorbents. In binary solutions, adsorption of CR/MO on CoFe2O4 better follows the pseudo-second-order kinetics model, while the kinetic of CR/MO adsorption on CoFe2O4–Chit is similar to that of the dyes in single-component solutions. Acetone and ethanol were successfully used as desorbing agents. (4) Conclusions: Our study revealed that CoFe2O4 and CoFe2O4–Chit particles are good candidates for dye-contaminated wastewater remediation.
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Nica, Valentin, Carlos Caro, Jose Maria Páez-Muñoz, Manuel Pernia Leal, and Maria Luisa Garcia-Martin. "Bi-Magnetic Core-Shell CoFe2O4@MnFe2O4 Nanoparticles for In Vivo Theranostics." Nanomaterials 10, no. 5 (May 8, 2020): 907. http://dx.doi.org/10.3390/nano10050907.

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In this work, we report the synthesis and characterization of three magnetic nanosystems, CoFe2O4, CoFe2O4@ZnFe2O4, and CoFe2O4@MnFe2O4, which were developed as potential theranostic agents for magnetic hyperthermia and magnetic resonance imaging (MRI). These nanosystems have been thoroughly characterized by X-ray Diffraction (XRD), Transmission Electron Miscroscopy (TEM), Dark Field-TEM (DF-TEM), Vibrating Sample Magnetometry (VSM), and inductive heating, in order to elucidate their structure, morphology, and magnetic properties. The bi-magnetic CoFe2O4@ZnFe2O4 and CoFe2O4@MnFe2O4 nanoparticles (NPs) exhibited a core-shell structure with a mean average particle size of 11.2 ± 1.4 nm and 14.4 ± 2.4 nm, respectively. The CoFe2O4@MnFe2O4 NPs showed the highest specific absorption rate (SAR) values (210–320 W/g) upon exposure to an external magnetic field, along with the highest saturation magnetization (Ms). Therefore, they were selected for functionalization with the PEGylated ligand to make them stable in aqueous media. After the functionalization process, the NPs showed high magnetic relaxivity values and very low cytotoxicity, demonstrating that CoFe2O4@MnFe2O4 is a good candidate for in vivo applications. Finally, in vivo MRI experiments showed that PEGylated CoFe2O4@MnFe2O4 NPs produce high T2 contrast and exhibit very good stealth properties, leading to the efficient evasion of the mononuclear phagocyte system. Thus, these bi-magnetic core-shell NPs show great potential as theranostic agents for in vivo applications, combining magnetic hyperthermia capabilities with high MRI contrast.
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Mubarok, Ahmad Thabib, Hendri Widiyandari, Utari, and Budi Purnama. "Annealing Temperature Effects in Co-Precipitated CoFe2O4 Nanoparticles Using Bengawan Solo River Fine Sediment." Key Engineering Materials 855 (July 2020): 64–69. http://dx.doi.org/10.4028/www.scientific.net/kem.855.64.

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In this study, the synthesis of CoFe2O4 by using the fine sediment of the Bengawan Solo River, Trucuk District, Bodjonegoro Regency as raw materials with the coprecipitation method has been successfully carried out. The fine sediment is used as a source of Fe cation in the synthesis of CoFe2O4. The XRD confirmation results showed that CoFe2O4 is formed at an annealing temperature of 800° C with crystallite sizes ranging from 34.88 to 38.05 nm. Thus, the VSM characterization showed that the magnetic properties of the CoFe2O4 nanoparticles depend on the heat treatment of the fine sediments as ore materials. Finally, the obtained CoFe2O4 samples can be used as photocatalysts with a maximum reduction rate ratio of 83%.
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Pasupong, Patchara, Kittisak Choojun, Naratip Vittayakorn, and Panpailin Seeharaj. "Synthesis of Nanocrystalline Cobalt Ferrite by the Sonochemical Method in Highly Basic Aqueous Solution." Key Engineering Materials 751 (August 2017): 368–73. http://dx.doi.org/10.4028/www.scientific.net/kem.751.368.

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This study reported the preparation of nanocrystalline CoFe2O4 in single step by the sonochemical method in highly basic aqueous solution without requiring of high temperature calcination process. To prepare nanocrystalline CoFe2O4, the mixed solution of the required molar ratio of cobalt nitrate hexahydrate (Co (NO3).6H2O) and ferric nitrate nonahydrate (Fe (NO3).9H2O) was precipitated in high concentration of sodium hydroxide medium solution (NaOH) under high intensity ultrasonic irradiation (20 kHz, 150 W/cm2). The effect of NaOH concentration (5, 10, 15 and 20 M) on phase formation, microstructure and magnetic property of CoFe2O4 was investigated. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and thermogravimetric analysis (TGA) results showed that the as-prepared powders were single phase CoFe2O4 with cubic spinel structure. Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) study showed that nanocrystalline CoFe2O4 had monosized distorted spherical morphology and an agglomeration of the nanocrystalline CoFe2O4 into nanoparticles was observed when increasing the NaOH concentration. The nanocrystalline CoFe2O4 exhibited superparamagnetic property and the saturation magnetization (Ms) obtained from vibrating sample magnetometry (VSM) was found to correlate with the crystallite size and varied from 39-45 emu/g.
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Ou, Tao, Hairong Peng, Minhua Su, Qingpu Shi, Jinfeng Tang, Nan Chen, and Diyun Chen. "Fast and Efficient Removal of Uranium onto a Magnetic Hydroxyapatite Composite: Mechanism and Process Evaluation." Processes 9, no. 11 (October 28, 2021): 1927. http://dx.doi.org/10.3390/pr9111927.

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The exploration and rational design of easily separable and highly efficient sorbents with satisfactory capability of extracting radioactive uranium (U)-containing compound(s) are of paramount significance. In this study, a novel magnetic hydroxyapatite (HAP) composite (HAP@ CoFe2O4), which was coupled with cobalt ferrite (CoFe2O4), was rationally designed for uranium(VI) removal through a facile hydrothermal process. The U(VI) ions were rapidly removed using HAP@ CoFe2O4 within a short time (i.e., 10 min), and a maximum U(VI) removal efficiency of 93.7% was achieved. The maximum adsorption capacity (Qmax) of the HAP@CoFe2O4 was 338 mg/g, which demonstrated the potential of as-prepared HAP@CoFe2O4 in the purification of U(VI) ions from nuclear effluents. Autunite [Ca(UO2)2(PO4)2(H2O)6] was the main crystalline phase to retain uranium, wherein U(VI) was effectively extracted and immobilized in terms of a relatively stable mineral. Furthermore, the reacted HAP@CoFe2O4 can be magnetically recycled. The results of this study reveal that the suggested process using HAP@CoFe2O4 is a promising approach for the removal and immobilization of U(VI) released from nuclear effluents.
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Zhang, Chunyang, Sanket Bhoyate, Chen Zhao, Pawan Kahol, Nikolaos Kostoglou, Christian Mitterer, Steven Hinder, et al. "Electrodeposited Nanostructured CoFe2O4 for Overall Water Splitting and Supercapacitor Applications." Catalysts 9, no. 2 (February 13, 2019): 176. http://dx.doi.org/10.3390/catal9020176.

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To contribute to solving global energy problems, a multifunctional CoFe2O4 spinel was synthesized and used as a catalyst for overall water splitting and as an electrode material for supercapacitors. The ultra-fast one-step electrodeposition of CoFe2O4 over conducting substrates provides an economic pathway to high-performance energy devices. Electrodeposited CoFe2O4 on Ni-foam showed a low overpotential of 270 mV and a Tafel slope of 31 mV/dec. The results indicated a higher conductivity for electrodeposited compared with dip-coated CoFe2O4 with enhanced device performance. Moreover, bending and chronoamperometry studies suggest excellent durability of the catalytic electrode for long-term use. The energy storage behavior of CoFe2O4 showed high specific capacitance of 768 F/g at a current density of 0.5 A/g and maintained about 80% retention after 10,000 cycles. These results demonstrate the competitiveness and multifunctional applicability of the CoFe2O4 spinel to be used for energy generation and storage devices.
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22

Dinh, Quang Thanh, Van Tuan Dinh, Hoai Nam Nguyen, Tien Anh Nguyen, Xuan Truong Nguyen, Luong Lam Nguyen, Thi Mai Thanh Dinh, Hong Nam Pham, and Van Quynh Nguyen. "Synthesis of magneto-plasmonic hybrid material for cancer hyperthermia." Journal of Military Science and Technology, no. 81 (August 26, 2022): 128–37. http://dx.doi.org/10.54939/1859-1043.j.mst.81.2022.128-137.

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Magnetic nanoparticle CoFe2O4-based hyperthermia is a promising non-invasive approach for cancer therapy. However, CoFe2O4 nanoparticles (NPs) have a low heat transfer efficiency, which limits their practical clinical applications. Hence, it is necessary to investigate the higher-performance magnetic NPs-based hybrid nanostructures to enhance their magnetic hyperthermia efficiency. This work presents a facile in situ approach for synthesizing cobalt ferrite (CoFe2O4) silver (Ag) hybrid NPs as optical-magnetic hyperthermia heat mediators. The prepared cobalt ferrite silver hybrid NPs exhibit a higher heat generation than that of individual Ag or CoFe2O4 NPs under simultaneous exposure to an alternating current magnetic field and laser source. The obtained results confirm that the hybridization of CoFe2O4 and Ag NPs could significantly enhance the hyperthermia efficiency of the prepared NPs. Therefore, the CoFe2O4-Ag hybrid NPs are considered as potential candidates for a high-performance hyperthermia mediator based on a simple and effective synthesis approach.
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23

Sin, Jin Chung, Sze Mun Lam, and Hong Hu Zeng. "Construction of Magnetic Z-Scheme P-Doped Biobr/CoFe<sub>2</sub>O<sub>4</sub> Nanocomposite for Expeditious Visible Light Photocatalytic Palm Oil Mill Effluent Degradation via the Assistance of IO<sub>4</sub><sup>-</sup> and S<sub>2</sub>O<sub>8</sub><sup>2-</sup>." Key Engineering Materials 938 (December 26, 2022): 163–69. http://dx.doi.org/10.4028/p-2yp25r.

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P-BiOBr/CoFe2O4 nanocomposite was fabricated through a surfactant-free hydrothermal route and combined with electron acceptors (IO4- and S2O82-) for the first time to examine the palm oil mill effluent (POME) degradation and concurrently evaluated the biogas formation under visible light irradiation. The POME degradation efficiency reached 100% in 120 min over P-BiOBr/CoFe2O4/IO4-, which was much higher than the P-BiOBr/CoFe2O4/S2O82- (80.6%). Interestingly, the evaluation of the biogas production demonstrated that the P-BiOBr/CoFe2O4/IO4- photocatalysis generated greater amount of biogas (CH4 + CO2) compared to other systems. The great photocatalytic enhancement was due to the efficient charge carrier separation thanks to the Z-scheme heterojunction between P-BiOBr and CoFe2O4, and the electron trapping by IO4-. The hydroxyl radicals and photogenerated holes contributed majorly to POME degradation. Ultimately, the P-BiOBr/CoFe2O4 with IO4- and S2O82- assisting under visible light provided an effective and feasible method to degrade POME.
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Gasim, Mohamed Faisal, Qing-Sheng Gooi, and Wen Da Oh. "Peroxymonosulfate activation using CoFe2O4/Fe2O3 nanocomposite for Acid Orange removal." Journal of Applied Materials and Technology 3, no. 2 (March 2, 2023): 34–43. http://dx.doi.org/10.31258/jamt.3.2.34-43.

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Herein, mixed–metal nanocomposite catalysts with various compositions (CoFe2O4/xFe2O3; x = 0, 0.25, 0.50, 0.75 and 1) were successfully fabricated by a co–precipitation method. The composition and morphology of the catalyst were systematically characterized. The catalyst with the highest Co content (CoFe2O4), exhibited the greatest efficiency for the acid orange 7 (AO7) degradation via peroxymonosulfate (PMS) activation. The effects of several experimental parameters including pH, CoFe2O4 loading, and PMS dosage on AO7 degradation were studied, and the catalytic activity was found to increase with the mentioned parameters. Moreover, CoFe2O4 displayed adequate reusability and was able to degrade AO7 for at least four consecutive cycles. In addition, the total organic carbon (TOC) removal of CoFe2O4 was determined while the catalyst stability was observed from the metal leaching in the treated solution. Furthermore, the magnetism of CoFe2O4 provides facile separation of the catalyst from the treated solution. Sulfate radicals (SO4•–) were identified as the main reactive species responsible for AO7 degradation.
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25

Rahmayeni,, Upita Septiani, Syukri Arief, and Hayatul Hamdi. "SINTESIS, KARAKTERISASI, DAN UJI AKTIFITAS FOTOKATALITIK NANOPARTIKEL MAGNETIK TiO2-CoFe2O4." Jurnal Riset Kimia 4, no. 2 (February 11, 2015): 71. http://dx.doi.org/10.25077/jrk.v4i2.134.

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ABSTRACT Magnetic nanoparticles of TiO2−CoFe2O4 were prepared using metal nitric and tiatniumisopropoxide as starting materials by coprecipitation and hydrolysis method. XRD, SEM, EDX and VSM were used to characterize the structure, morphology, composition and magnetic property of the particles, respectively. XRD pattern show the diffraction peaks of TiO2 anatase at 2θ = 25.3° and CoFe2O4 at 2θ = 35.5° in TiO2−CoFe2O4 particles. SEM image show the regular morphology and size distribution of particles. From VSM analysis indicate that the particles have paramagnetic properties. Photocatalytic activities of particles were applied for degradation of rhodamin B and the results showed that CoFe2O4 doped into TiO2 can increase the activities of particles in visible light until 82 %. Key words : nanopartikel magnetik, TiO2−CoFe2O4, fotokatalis
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26

An, Ji-Bin, Dai-Peng Hu, Yan-Lin Li, and Na-Li Chen. "Efficient Degradation of Atrazine by Magnetic CoFe2O4/g-C3N4 Catalyzed Peroxymonosulfate and Its Enhancement of Photocatalytic Ability Under Visible-Light." Science of Advanced Materials 11, no. 12 (December 1, 2019): 1764–72. http://dx.doi.org/10.1166/sam.2019.3572.

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The Magnetic photocatalytic cobalt ferrite/graphitic-carbon nitride (CoFe2O4/g-C3N4) composites with enhanced photocatalytic activity were successfully fabricated through a simple calcination method. Scanning electron microscopy, powder X-ray diffraction, and infrared spectroscopy were applied to characterize the samples. The photocatalytic behavior of CoFe2O4/g-C3N4 was assessed by degradation of atrazine in photo Fenton-like system under visible light irradiation. The results showed that CoFe2O4/g-C3N4 with 2.0 gL–1 catalyst loading in the presence of 1 mM peroxymonosulfate (PMS) exhibited the best catalytic performance, and more than 97% of atrazine was destructed in 12 min. This enhancement could be attributed to the synergistic effect between CoFe2O4 and g-C3N4 promoting longer lifetime of separated electron–hole pairs derived from the formation of the heterojunction between CoFe2O4 and g-C3N4. This could enhance the composite-mediated activation of PMS for the visible-light driven degradation of atrazine. Moreover, the quenching tests showed that sulfate radicals were responsible for the atrazine degradation. CoFe2O4/g-C3N4 composites have strong magnetic ability, thus their recovery from water could be readily achieved by applying external magnetic field. This study demonstrates reasonable performance of the PMS/CoFe2O4/g-C3N4 system in water matrix as potentially important candidate for environmental remediation.
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27

Park, Bong Joo, Kyong-Hoon Choi, Ki Chang Nam, Jeeeun Min, Kyu-Dong Lee, Han Sup Uhm, Eun Ha Choi, Ho-Joong Kim, and Jin-Seung Jung. "Photodynamic Anticancer Activity of CoFe2O4 Nanoparticles Conjugated with Hematoporphyrin." Journal of Nanoscience and Nanotechnology 15, no. 10 (October 1, 2015): 7900–7906. http://dx.doi.org/10.1166/jnn.2015.11236.

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This work reports the synthesis and the characterization of water-soluble and biocompatible photosensitizer (PS)-conjugated magnetic nanoparticles composed of a cobalt ferrite (CoFe2O4) magnetic core coated with a biocompatible hematoporphyrin (HP) shell. The photo-functional cobalt ferrite magnetic nanoparticles (CoFe2O4@HP) were uniform in size, stable against PS leaching, and highly efficient in the photo-generation of cytotoxic singlet oxygen under visible light. With the CoFe2O4@HP, we acquired in vitro MR images of cancer cells (PC-3) and confirmed good biocompatibility of the CoFe2O4@HP in both normal and cancer cells. In addition, we confirmed the potential of the CoFe2O4@HP as an agent for photodynamic therapy (PDT) applications. The photodynamic anticancer activities in 25, 50, and 100 μg/mL of CoFe2O4@HP were measured and found to exceed 99% (99.0, 99.4, and 99.5%) (p <0.002). The photodynamic anticancer activity was 81.8% (p < 0.003). From these results, we suggest that our CoFe2O4@HP can be used safely as a type of photodynamic cancer therapy with potential as a therapeutic agent having good biocompatibility. Moreover, these photo-functional magnetic nanoparticles are highly promising for applications in versatile imaging diagnosis and as a therapy tool in biomedical engineering.
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Bortnic, Rareș, Adam Szatmari, Gabriela Souca, Răzvan Hirian, Roxana Dudric, Lucian Barbu-Tudoran, Valentin Toma, Rareș Știufiuc, Romulus Tetean, and Emil Burzo. "New Insights into the Magnetic Properties of CoFe2O4@SiO2@Au Magnetoplasmonic Nanoparticles." Nanomaterials 12, no. 6 (March 12, 2022): 942. http://dx.doi.org/10.3390/nano12060942.

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We report the successful synthesis and a complete magnetic characterization of CoFe2O4@SiO2@Au magnetoplasmonic nanoparticles. The CoFe2O4 magnetic nanoparticles were prepared using the hydrothermal method. A subsequent SiO2 shell followed by a plasmonic Au shell were deposited on the magnetic core creating magnetoplasmonic nanoparticles with a core–shell architecture. A spin-glass-type magnetism was shown at the surface of the CoFe2O4 nanograins. Depending on the external magnetic field, two types of spin-glass were identified and analyzed in correlation with the exchange field acting on octahedral and tetrahedral iron sites. The magnetization per formula unit of the CoFe2O4 core is not changed in the case of CoFe2O4@SiO2@Au nanocomposites. The gold nanoparticles creating the plasmonic shell show a giant diamagnetic susceptibility, dependent on their crystallite sizes.
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29

Wang, Bao Wen, Chuan Chang Gao, Hai Bo Zhao, and Chu Guang Zheng. "Preparation of CoFe2O4 Nanocrystallite by Sol-Gel Combustion Synthesis and Evaluation of its Reaction Performance." Advanced Materials Research 341-342 (September 2011): 63–67. http://dx.doi.org/10.4028/www.scientific.net/amr.341-342.63.

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Sol-gel combustion synthesis method was adopted to prepare nano-sized CoFe2O4 using urea as fuel. The as-synthesized CoFe2O4 powders were characterized through such experimental means as Fourier transform infrared spectroscopy (FTIR), TG (thermogravimetric)–DSC (differential scanning calorimetry), X-ray diffraction (XRD), field-scanning electron microscopy (FSEM). FTIR analysis and XRD analysis revealed that the dried CoFe2O4 gel was formed by the coordination of metal with O, and consisted of various phases through the hydrolysis of urea and metal nitrates along with the coordination of the various groups produced. And then, TG-DSC analysis of the dried CoFe2O4 gel under air atmosphere indicated that there are two remarkable exothermic reactions occurring, related to the redox reactions between urea and nitrates used, and as-synthesized CoFe2O4 was porous due to the emission of large amount of gases during preparation. Finally, three cycles of temperature-programmed reduction (TPR) coupled with temperature-programmed oxidization (TPO) tests were conducted on the AutoChem 2920 system to show the good reaction and sintering-resistance performance for the synthesized CoFe2O4.
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30

Lu, Zhong Li, Hui Zhang, and Xue Duan. "Synthesis, Characterization and Catalytic Property of Nanoscale Magnetic Photocatalyst Titania/Silica/Cobalt Ferrite." Advanced Materials Research 11-12 (February 2006): 611–14. http://dx.doi.org/10.4028/www.scientific.net/amr.11-12.611.

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Magnetic material CoFe2O4 was prepared via layered precursor method. Magnetic nanosized photocatalyst TiO2/SiO2/CoFe2O4 was synthesized by hydrolysis titanium bis- ammonium lactato dihydroxide into photoactive TiO2 onto silica-modified CoFe2O4. Based on XRD, FT-IR, VSM analysis and catalytic evaluation, as-synthesized magnetic photocatalyst possess core-shell structure and exhibits evident photodegradation activity for methyl orange.
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31

Cui, Haipeng, Pengfei Zhao, Lusheng Liao, Yanfang Zhao, Aichun Long, and Jianhe Liao. "Preparation and properties of natural rubber composite with CoFe2O4-immobilized biomass carbon." e-Polymers 22, no. 1 (January 1, 2022): 214–22. http://dx.doi.org/10.1515/epoly-2022-0025.

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Abstract Designing versatile rubber as a multifunctional elastomer is of great importance, incorporating it with biomass-derived nanoblocks will mitigate environmental challenges. Here biosynthesized natural rubber (NR) composites with CoFe2O4-immobilized biomass carbon (BC) derived from macadamia nutshells were fabricated by facile mechanical mixing. Morphological analysis indicates that CoFe2O4 nanoparticles are uniformly anchored on the surface of BC, forming intact electromagnetic loss networks in NR matrix. As a consequence, the as-fabricated NR/CoFe2O4@BC composites demonstrate enhanced mechanical, thermal, and electromagnetic performance. Particularly, NR/CoFe2O4@BC composite shows the best microwave attenuation capacity when CoFe2O4@BC loading is 40 phr, with the minimum reflection loss (RL) of −35.00 dB and effective absorption bandwidth (RL < −10 dB) of 1.60 GHz. All results indicate that this work open new paradigm for multiple applications based on biosynthetic elastomer with the sustainable biomass derived nanoblocks.
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32

Cintron-Nuñez, P. C., B. Escobar-Morales, J. Escorcia-Garcia, F. J. Rodríguez-Varela, and I. L. Alonso-Lemus. "Electrospun CoFe2O4 nanofibers as bifunctional nanocatalysts for the oxygen evolution and oxygen reduction reactions in alkaline media." MRS Advances 5, no. 57-58 (2020): 2929–37. http://dx.doi.org/10.1557/adv.2020.380.

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AbstractNon-noble metal bifunctional nanocatalysts based on CoFe2O4/C were synthetized by the electrospinning method and evaluated for the Oxygen Evolution Reaction (OER) and the Oxygen Reduction Reaction (ORR). The effect of annealing at different temperatures (T=300, 600 and 900°C) on their morphological and structural features was characterized by XRD, EDS, Raman, FESEM, HRTEM and XPS. The nanofibers annealed at 300 °C (CoFe2O4-300) showed a cubic spinel structure and an average diameter of 42 nm. The CoFe2O4-300/C nanocatalyst demonstrated the highest catalytic activity towards the OER, outperforming the benchmark commercial 20 wt. % Pt/C. Meanwhile all CoFe2O4-based nanocatalysts showed fair catalytic activity for the ORR (Eonset ≈ 0.801 V/RHE, n≈ 3.56, %HO2- ≈ 21-39). In addition, the CoFe2O4/C nanocatalysts demonstrated a higher electrochemical stability than Pt/C for both the ORR and the OER.
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33

Zhou, Xiang-Jun, Yan-Yan Wang, and Zhou Wang. "Adsorption Performances and Electrochemical Properties of Methyl Blue onto CoFe2O4 Nanoparticles." Journal of Nanoscience and Nanotechnology 21, no. 4 (April 1, 2021): 2203–11. http://dx.doi.org/10.1166/jnn.2021.19037.

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Magnetic CoFe2O4 nanoparticles were successfully manufactured through the process of nitrate combustion using anhydrous ethanol as fuel, they together with their intermediate were characterized by thermo gravimetric (TG) analysis, selected area electron diffraction (SAED), transmission electron microscope (TEM), vibrating sample magnetometer (VSM), and X-ray diffraction (XRD). These results indicated a phenomenon that the magnetic CoFe2O4 nanoparticles could be formed at 400 °C, the average grain size, the specific magnetization, and the specific surface area of magnetic CoFe2O4 nanoparticles fabricated at 400 °C for 2 h with 30 mL anhydrous ethanol were corresponding 20 nm, 78.0 Am2/kg and 83.2 m2/kg. Magnetic CoFe2O4 nanoparticles were in application to adsorb methyl blue (MB) of wastewater, and their adsorption performances and electrochemical properties were investigated, the adsorption process data well agreed with the pseudo-second-order kinetics model in concentration ranging from 100 mg/L to 400 mg/L of MB. Compared with Freundlich model, Langmuir model (correlation coefficient R2 = 0.9976) could evaluate the adsorption equilibrium state of MB onto CoFe2O4 nanoparticles at indoor temperature, so the monomolecular layer adsorption mechanism was demonstrated to be the mechanism of the MB molecules' adsorption onto CoFe2O4 nanoparticles.
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34

Zeng, Lingyu, Yecan Peng, Guirong Ye, Xiaona Shang, Shuangfei Wang, and Jinghong Zhou. "Adsorption of organic matter from papermaking wastewater by CoFe2O4-coated sand in batch and fixed-bed systems." BioResources 16, no. 3 (July 2, 2021): 5806–20. http://dx.doi.org/10.15376/biores.16.3.5806-5820.

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The secondary treated effluents of pulp and paper mills contain high chemical oxygen demand (COD) that is associated with organic matter. Therefore, this study explores the adsorption of substances contributing to COD using CoFe2O4 and quartz sand-coated CoFe2O4 in batch and fixed-bed column experiments. X-ray diffraction, scanning electron microscopy, Brunauer–Emmett–Teller analysis, and X-ray photoelectron spectroscopy were used to characterize the adsorbents. The quartz sand-loaded CoFe2O4 exhibited a larger pore volume and average pore size. Batch experiments revealed that adsorption on CoFe2O4 closely fit the pseudo-second-order model. To explore the effects of bed depth, feed flow rate, and initial solution pH on the breakthrough characteristics of CoFe2O4-coated sand, fixed-bed column experiments were conducted, and the breakthrough curves were drawn from the ratio of influent COD concentration to effluent COD concentration. The breakthrough time decreased with an increase in the feed flow rate and initial pH but increased with the bed depth. According to the X-ray photoelectron spectroscopy analysis, CoFe2O4-coated sand showed excellent stability due to negligible leaching of metallic elements. These findings have important implications for the advanced treatment of industrial wastewater.
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35

Liu, Chao, Adam J. Rondinone, and Z. John Zhang. "Synthesis of magnetic spinel ferrite CoFe2O4 nanoparticles from ferric salt and characterization of the size-dependent superparamagnetic properties." Pure and Applied Chemistry 72, no. 1-2 (January 1, 2000): 37–45. http://dx.doi.org/10.1351/pac200072010037.

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The CoFe2O4 nanoparticles have been synthesized by using a stable ferric salt of FeCl3 with a micellar microemulsion method. The normal micelles are formed by sodium dodecyl sulfate (NaDS) in aqueous solutions. The mean size of the nanoparticles can be controlled from less than 4 nm to about 10 nm through controlling the concentrations of the reagents. The neutron diffraction in combination with the Rietveld refinement shows that these CoFe2O4 nanoparticles have a high degree of inversion with 66% of the tetrahedral sublattice occupied by Fe3+. Magnetic measurements and neutron diffraction studies demonstrate the superparamagnetic nature of these CoFe2O4 nanoparticles. The size-dependent superparamagnetic properties of CoFe2O4 nanoparticles have also been systematically studied. The blocking temperature and coercive field of the nanoparticles increase with increasing size of the nanoparticles. The superparamagnetic behaviors of CoFe2O4 nanoparticles are consistent with the Stoner-Wohlfarth theory of single domain particles.
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36

Omelyanchik, Alexander, Silvia Villa, Gurvinder Singh, Valeria Rodionova, Sara Laureti, Fabio Canepa, and Davide Peddis. "Magnetic Properties of Bi-Magnetic Core/Shell Nanoparticles: The Case of Thin Shells." Magnetochemistry 7, no. 11 (November 8, 2021): 146. http://dx.doi.org/10.3390/magnetochemistry7110146.

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Bi-magnetic core/shell nanoparticles were synthesized by a two-step high-temperature decomposition method of metal acetylacetonate salts. Transmission electron microscopy confirmed the formation of an ultrathin shell (~0.6 nm) of NiO and NiFe2O4 around the magnetically hard 8 nm CoFe2O4 core nanoparticle. Magnetization measurements showed an increase in the coercivity of the single-phase CoFe2O4 seed nanoparticles from ~1.2 T to ~1.5 T and to ~2.0 T for CoFe2O4/NiFe2O4 and CoFe2O4/NiO, respectively. The NiFe2O4 shell also increases the magnetic volume of particles and the dipolar interparticle interactions. In contrast, the NiO shell prevents such interactions and keeps the magnetic volume almost unchanged.
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37

Liu, Yin, Fan Fei Min, Tai Qiu, Jin Bo Zhu, and Ming Xu Zhang. "Effect of the Grain Size on Magnetic Properties of Nanocrystalline CoFe2O4 Ferrite." Advanced Materials Research 308-310 (August 2011): 685–88. http://dx.doi.org/10.4028/www.scientific.net/amr.308-310.685.

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Nanocrystalline CoFe2O4 ferrite have been synthesized by a spraying-coprecipitation method. X-ray diffraction (XRD) and Transmission electron microscope (TEM) confirmed the formation of single-phase CoFe2O4 ferrite nanoparticles in the range 10 nm ~ 100 nm depending on the calcining temperature. The magnetic measurements show that specific saturation magnetization of nanocrystalline CoFe2O4 ferrite increases from 36.1 A•m2•kg-1 to 88.6 A•m2•kg-1 as grain size increases from 12 nm to 98 nm. The coercivity shows a peak with grain size, peaking at around 43 nm. The magnetic behaviour of nanocrystalline CoFe2O4 ferrite might be attributed to the effects of surface and random anisotropy.
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38

Araújo, P. M. A. G., N. G. Araújo, M. R. Silva, S. M. C. M. Bicalho, and A. C. F. M. Costa. "Estudo do efeito da modificação de superfície de Fe3O4 e CoFe2O4 para aplicação como carreador de fármaco." Cerâmica 64, no. 372 (December 2018): 466–76. http://dx.doi.org/10.1590/0366-69132018643722379.

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Resumo Neste trabalho foram propostos obter e caracterizar o Fe3O4 e o CoFe2O4 associados ao tetraetilortossilicato (TEOS) e do 3-aminopropiltrimetoxissilano (APTS), visando avaliar o efeito da modificação de superfície das partículas magnéticas sobre as propriedades estrutural, morfológica e magnéticas para aplicação como carreador de fármaco. As amostras foram caracterizadas por difração de raios X, espectroscopia no infravermelho com transformada de Fourier, análise textural, microscopia eletrônica de varredura e medidas magnéticas. A partir dos resultados observou-se que o Fe3O4 e o CoFe2O4 foram sintetizados com sucesso. A presença da fase principal do Fe3O4 foi notada no sistema obtido com o Fe3O4/SiO2 e CoFe2O4 no sistema obtido com o CoFe2O4/SiO2. A formação dos híbridos (core-shell) foi confirmada pela presença de bandas características da sílica. Os sistemas obtidos com o Fe3O4 apresentaram diâmetros de partícula superiores aos formados com o CoFe2O4, ambos formados de aglomerados de tamanho e formato irregulares e com comportamento típico de materiais ferrimagnéticos.
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39

Alharthy, Rima D., and Ahmed Saleh. "A Novel Trace-Level Ammonia Gas Sensing Based on Flexible PAni-CoFe2O4 Nanocomposite Film at Room Temperature." Polymers 13, no. 18 (September 12, 2021): 3077. http://dx.doi.org/10.3390/polym13183077.

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In this study, we developed a new chemi-resistive, flexible and selective ammonia (NH3) gas sensor. The sensor was prepared by depositing thin film of polyaniline-cobalt ferrite (PAni-CoFe2O4) nanocomposite on flexible polyethylene terephthalate (PET) through an in situ chemical oxidative polymerization method. The prepared PAni-CoFe2O4 nanocomposite and flexible PET-PAni-CoFe2O4 sensor were evaluated for their thermal stability, surface morphology and materials composition. The response to NH3 gas of the developed sensor was examined thoroughly in the range of 1–50 ppm at room temperature. The sensor with 50 wt% CoFe2O4 NPs content showed an optimum selectivity to NH3 molecules, with a 118.3% response towards 50 ppm in 24.3 s response time. Furthermore, the sensor showed good reproducibility, ultra-low detection limit (25 ppb) and excellent flexibility. In addition, the relative humidity effect on the sensor performance was investigated. Consequently, the flexible PET-PAni-CoFe2O4 sensor is a promising candidate for trace-level on-site sensing of NH3 in wearable electronic or portable devices.
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40

Chen, Peng, Lin-Wen Jiang, Shan-Shan Yang, Hong-Bing Chen, Jun He, Yu Wang, and Jing An. "Facile Synthesis and Microwave-Absorption Properties of Organic–Inorganic CoFe2O4/Polyaniline Nanocomposites with Embedded Structure." Journal of Nanoscience and Nanotechnology 20, no. 3 (March 1, 2020): 1756–64. http://dx.doi.org/10.1166/jnn.2020.17150.

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Organic–inorganic CoFe2O4/polyaniline (CoFe2O4/PA) nanocomposites with embedded structures were synthesized by combining the sol–gel auto-combustion process and in-situ oxidative polymerization. The phases and morphologies of the prepared samples were identified. The pure CoFe2O4 samples exhibited inferior microwave-absorption properties in a frequency range of 2–18 GHz. Upon the incorporation of PA, the formed CoFe2O4/PA nanocomposites exhibited rather good absorption performances. When the sample thickness was 2.5 mm, the maximum reflection loss (RL) reached -22.3 dB, while the RL below -10 dB corresponded to the range of 11.0–17.1 GHz, which contains almost the entire Ku-band, making the structure promising for commercial and military applications. A physical model was employed to explain the effects of the embedded structure on the microwave-absorption performances. The excellent microwave-absorption performances could be attributed to the interfacial polarization and repeated reflection of the microwaves inside the CoFe2O4/PA composite.
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41

Berbenni, Vittorio, Chiara Milanese, Giovanna Bruni, Alessandro Girella, and Amedeo Marini. "Mechanothermal Solid-state Synthesis of Cobalt(II) Ferrite and Determination of its Heat Capacity by MTDSC." Zeitschrift für Naturforschung B 65, no. 12 (December 1, 2010): 1434–38. http://dx.doi.org/10.1515/znb-2010-1204.

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Cobalt ferrite (CoFe2O4) has been synthesized by a solid-state mechanothermal process, and its molar heat capacity has been determined. A stoichiometric mixture of CoC2O4 ・ 2H2O and FeC2O4 ・ 2H2O was subjected to a combination of mechanical activation (by high-energy milling) and thermal activation (by annealing at temperatures between 300 and 700 °C). The process was followed by thermogravimetric analysis and high-temperature X-ray powder diffraction. It has been shown that CoFe2O4 forms at all temperatures, though with different degrees of crystallization, while Co3O4 and Fe2O3 are the only products formed when starting from unmilled mixtures. The molar heat capacity of CoFe2O4 has been determined in the temperature range 60 - 400 °C by MTDSC. It has been shown that the molar CP values of CoFe2O4 samples produced at T ≥ 500 °C are close to each other while those of the samples produced at 300 and 400 °C are lower. Furthermore the CoFe2O4 samples prepared at T ≥ 500 °C show very similar microstructures.
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42

Zhao, Yuhao, Kai Xia, Zhenzong Zhang, Ziming Zhu, Yongfu Guo, and Zan Qu. "Facile Synthesis of Polypyrrole-Functionalized CoFe2O4@SiO2 for Removal for Hg(II)." Nanomaterials 9, no. 3 (March 19, 2019): 455. http://dx.doi.org/10.3390/nano9030455.

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In order to avoid using toxic or harmful operational conditions, shorten synthesis time, enhance adsorption capacity, and reduce operational cost, a novel magnetic nano-adsorbent of CoFe2O4@SiO2 with core–shell structure was successfully functionalized with polypyrrole (Ppy). The physical and chemical properties of CoFe2O4@SiO2-Ppy are examined by various means. The as-prepared CoFe2O4@SiO2-Ppy nanomaterial was used to adsorb Hg2+ from water. During the process, some key effect factors were studied. The adsorption process of Hg2+ onto CoFe2O4@SiO2-Ppy was consistent with the pseudo-second-order kinetic and Langmuir models. The Langmuir capacity reached 680.2 mg/g, exceeding those of many adsorbents. The as-prepared material had excellent regeneration ability, dispersibility, and stability. The fitting of kinetics, isotherms, and thermodynamics indicated the removal was endothermic and spontaneous, and involved some chemical reactions. The application evaluation of electroplating wastewater also shows that CoFe2O4@SiO2-Ppy is an excellent adsorbent for Hg2+ ions from water.
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43

JIN, HONGXIAO, LIANG LI, MIN CHEN, JINGCAI XU, BO HONG, BAO HUANG, DINGFENG JIN, HONGLIANG GE, and XINQING WANG. "SYNTHESIS OF MAGNETIC SBA-15 AND Fe–SBA-15 MESOPOROUS NANOCOMPOSITES WITH COBALT FERRITES." Nano 06, no. 03 (June 2011): 287–93. http://dx.doi.org/10.1142/s1793292011002512.

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A new nanocomposite based on SBA-15 mesoporous materials combined with Fe2O3 and CoFe2O4 nanoparticles was prepared via sol–gel growth. The nanostructures and magnetic properties of the SBA-15 nanocomposite were investigated by X-ray diffraction topography, high resolution transmission electron microscopy, and vibrating sample magnetometer. Results indicate that α- Fe2O3 nanoparticles are present in the frame or micropores of SBA-15 (denoted as Fe –SBA-15 below) and that CoFe2O4 nanoparticles are confined in the mesoporous channels of Fe –SBA-15. Our results also reveal that the addition of CoFe2O4 and α- Fe2O3 magnetic nanoparticles critically affects their magnetic properties. The saturation magnetization of the SBA-15 nanocomposite is attributed to ferrimagnetic CoFe2O4 nanoparticles and antiferromagnetic α- Fe2O3 nanoparticles, whereas the coercivity increases with the content of CoFe2O4 . Moreover, the presence of the couple exchange interaction between the magnetic nanoparticles is confirmed, which can enhance the magnetic properties of the SBA-15 nanocomposite.
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44

Zhang, Ling, Ji Wei Zhai, Wei Feng Mo, and Xi Yao. "Dielectric and Magnetic Properties of CoFe2O4-BaTiO3 Composite Thick Film." Key Engineering Materials 421-422 (December 2009): 219–22. http://dx.doi.org/10.4028/www.scientific.net/kem.421-422.219.

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(x)CoFe2O4-(1-x) BaTiO3 thick film with x=0.2 was prepared by electrophoretic deposition technique using BaTiO3 and CoFe2O4 nanopowders. X-ray diffraction indicated the film was consisted of single spinel CoFe2O4 and perovskite BaTiO3 phase. The thick film exhibited good ferromagnetic and ferroelectric property. The dielectric properties were influenced by ferromagnetic phase, especially at low frequency and high temperature, which was attributed to space charge effects and Maxwell-Wagner relaxation.
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45

Piravadili Mucur, Selin, Betül Canimkurbey, and Ayse Demir Korkmaz. "Magnetic Field Implementing into the Electroluminescence of OLED Devices Doped with CoFe2O4 Nanoparticles." Volume 28, Number 2, 2020, no. 02-2020 (April 2020): 95–105. http://dx.doi.org/10.33383/2019-021vol.

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Cobalt ferrite magnetic nanoparticles (CoFe2O4 MNPs) were successfully prepared by citric acid-assisted sol-gel auto combustion method and used in emissive layer of organic light emitting diode (OLED). Dimensional, structural and magnetic properties of CoFe2O4 nanoparticles (NPs) were recearched and compared by using X-ray diffraction (XRD), scanning electron microscopy (SEM), and vibrating sample magnetometer (VSM). CoFe2O4 MNPs were utilized at various concentrations (0.5 wt%, 1.0 wt% and 2.0 wt%) in the emissive layer of the OLEDs. The luminance, current efficiency and the electroluminescence characteristics of the devices with and without CoFe2O4 MNPs were investigated. An external magnetic field, Bext, has also been applied to the OLEDs doped with MNPs while under operation. Effects of MNPs on OLED characteristics under Bext were studied thoroughly. In the tailored device architecture, poly (3,4-ethylenedioxythiophene): poly polystyrene sulphonate (PEDOT: PSS) and poly(2-methoxy-5-(2-ethylhexyloxy))-1,4-phenylene vinylene (MEH-PPV) were used as a hole transport layer (HTL) and an emissive layer respectively with ITO/PEDOT: PSS/ MEH-PPV: CoFe2O4/Ca/Al device architecture. The obtained results of the fabricated OLEDs were enhanced in the presence of CoFe2O4 NPs under Bext due to providing density of states in the polymer matrices. The turn-on voltage was diminished slightly in the device doped with 0.5 % wt MNP compared to the devices with other concentrations of MNPs.
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46

Yu, Wenli, Zhi Chen, Weiping Xiao, Yongming Chai, Bin Dong, Zexing Wu, and Lei Wang. "Phosphorus doped two-dimensional CoFe2O4 nanobelts decorated with Ru nanoclusters and Co–Fe hydroxide as efficient electrocatalysts toward hydrogen generation." Inorganic Chemistry Frontiers 9, no. 8 (2022): 1847–55. http://dx.doi.org/10.1039/d2qi00086e.

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Phosphorus doped two-dimensional CoFe2O4 nanobelts decorated with Ru and CoFe hydroxide clusters on iron foam (CoFeOxHy–Ru/P–CoFe2O4/IF) are synthesized as efficient electrocatalysts for the highly electrocatalytic HER.
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47

Hernández, Rebeca, German López, Daniel López, Manuel Vázquez, and Carmen Mijangos. "Magnetic characterization of polyvinyl alcohol ferrogels and films." Journal of Materials Research 22, no. 8 (August 2007): 2211–16. http://dx.doi.org/10.1557/jmr.2007.0298.

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This study elucidates the tunability of the magnetic properties of cobalt spinel ferrites embedded in a polyvinyl alcohol (PVA) hydrogel by changing the structure of the polymer network. We report on the preparation and characterization of sPS-CoFe2O4 ferrofluid and PVA/sulfonated polystyrene (sPS)-CoFe2O4 ferrogels obtained by submitting the samples to a different number of freezing–thawing (F–T) cycles. The magnetic properties were evaluated and interpreted as a function of the PVA/sPS-CoFe2O4 composition and final structure of the ferrogels.
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48

Балаев, Д. А., С. В. Семенов, А. А. Дубровский, А. А. Красиков, С. И. Попков, С. С. Якушкин, В. Л. Кириллов, and О. Н. Мартьянов. "Синтез и магнитные свойства наночастиц Fe-=SUB=-3-=/SUB=-O-=SUB=-4-=/SUB=-/CoFe-=SUB=-2-=/SUB=-O-=SUB=-4-=/SUB=- со структурой ядро/оболочка." Физика твердого тела 62, no. 2 (2020): 235. http://dx.doi.org/10.21883/ftt.2020.02.48874.581.

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Fe3O4 / CoFe2O4 nanoparticles with a core-shell structure with an average size of 5 nm were obtained by co-precipitation from solutions of iron and cobalt chlorides. An analysis of the magnetic properties of the resulting system and their comparison with the data for single-phase Fe3O4 (4 nm) and CoFe2O4 (6 nm) nanoparticles led to the conclusion that there is a noticeable interaction between the soft magnetic (Fe3O4) and magnetically hard (CoFe2O4) phases that form the core and the shell of hybrid particles, correspondingly.
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49

Primadi, Thutug Rahadiant, Fauziatul Fajaroh, Aman Santoso, Nazriati, and Endang Ciptawati. "Synthesis of CaO@CoFe2O4 Nanoparticles and its Application as a Catalyst for Biodiesel Production from Used Cooking Oil." Key Engineering Materials 851 (July 2020): 184–93. http://dx.doi.org/10.4028/www.scientific.net/kem.851.184.

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Until now, used cooking oil (jelantah) has not been utilized optimally. This study seeks to convert this waste into biodiesel. Used cooking oil usually contains high concentration of free fatty acids which can be converted into methyl esters through trans-esterification by methanol. This effort is in line with the increasing need for renewable energy sources. Because the waste still contains high concentrations of free fatty acids, it is necessary to think about the right process and catalyst in converting it as biodiesel. One heterogeneous catalyst that is thought to excel in biodiesel production is ferrite-based nanocomposites, namely CaO@CoFe2O4 nanoparticles. The advantages of this catalyst are: it has high reactivity, thermal and chemical stability, and can be drawn by magnetic fields. This last property facilitates the catalyst isolation at the end of the process for recycling purposes. The catalytic power is expected to increase through impregnation with alkaline earth metal oxides which have a relatively high basicity, namely CaO. The purpose of this study was to synthesize and to characterize CaO@CoFe2O4, then to study its potential catalytic in biodiesel production from used cooking oil in various weight percent of catalyst. The main steps include: (1) synthesis of CoFe2O4 by coprecipitation; (2) Impregnation of CaO into CoFe2O4 and converted to CaO@CoFe2O4; (3) Characterization of the synthesized material by XRD, BET, and SEM/EDX; (4) application of CaO@CoFe2O4 in biodiesel production from used cooking oil; (5) characterization of biodiesel produced by viscosity measurement, yield and GC-MS analysis results. Based on the results of XRD and SEM/EDX analysis, the CaO@ CoFe2O4 catalyst has been successfully synthesized. Under optimal conditions, the yield of methyl ester produced with the addition of 2% of catalyst was 80.62%.
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50

Roslan, Anis Arisa, Hasnah Mohd Zaid, Siti Nur Azella Zaine, Mursyidah Umar, and Beh Hoe Guan. "Characterization and Nanofluid Stability of CoFe2O4-APTES and CoFe2O4-PVA Nanoparticles." Journal of Advanced Research in Fluid Mechanics and Thermal Sciences 78, no. 1 (December 1, 2020): 79–87. http://dx.doi.org/10.37934/arfmts.78.1.7987.

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Nanofluid contains nanoparticles that enhanced the property of the base fluid. However, the separating layer between the nanoparticles and base fluids may interfere the nanofluids performance. Studies have been made that surface modification of nanoparticles may improve the dispersion of nanoparticles in base fluids. This paper reports the study of the colloidal stability of surface modified nanoparticles using a polymer and an amino-silane. The nanoparticles were prepared by one-step and two-step methods using cobalt iron oxide nanoparticles with brine solution and deionized water as the base fluids. Functionalization by surface modification of the nanoparticles to enhance the nanofluids stability was carried out using (3-aminopropyl) triethoxysilane (APTES) and polyvinyl alcohol (PVA). Characterization using Fourier Transform Infrared (FTIR), Field Emission Scanning Electron Microscope (FESEM) and X-ray Powder Diffraction (XRD) were performed to study the functionality and morphology of the synthesized nanoparticles. The extra IR peaks such as Si-O-Si at 1063 cm-1 for CoFe2O4-APTES and C=O at 1742 cm-1 for CoFe2O4-PVA showed that there are additional elements in the cobalt ferrite due to functionalization. The size of synthesized CoFe2O4-APTES ranged between 15.99 nm to 26.89 nm while CoFe2O4-PVA is from 25.70 nm to 54.16 nm. The stability of the nanofluid were determined via zeta potential measurements. CoFe2O4-APTES nanofluid has zeta potential of -35.7 mV compared to CoFe2O4-PVA at -15.5 mV.
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