spinel type
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Batteries ◽  
2022 ◽  
Vol 8 (1) ◽  
pp. 5
Author(s):  
Lukman Noerochim ◽  
Alvalo Toto Wibowo ◽  
Widyastuti ◽  
Achmad Subhan ◽  
Bambang Prihandoko ◽  
...  

Graphite as a commercial anode for lithium-ion batteries has significant safety concerns owing to lithium dendrite growth at low operating voltages. Li4Ti5O12 is a potential candidate to replace graphite as the next-generation anode of lithium-ion batteries. In this work, fluoride-doped Li4Ti5O12 was successfully synthesized with a direct double coating of carbon and nitrogen using a solid-state method followed by the pyrolysis process of polyaniline. X-ray diffraction (XRD) results show that the addition of fluoride is successfully doped to the spinel-type structure of Li4Ti5O12 without any impurities being detected. The carbon and nitrogen coating are distributed on the surface of Li4Ti5O12 particles, as shown in the Scanning Electron Microscopy–Energy Dispersive X-ray Spectroscopy (SEM-EDS) image. The Transmission Electron Microscopy (TEM) image shows a thin layer of carbon coating on the Li4Ti5O12 surface. The fluoride-doped Li4Ti5O12 has the highest specific discharge capacity of 165.38 mAh g−1 at 0.5 C and capacity fading of 93.51% after 150 cycles compared to other samples, indicating improved electrochemical performance. This is attributed to the synergy between the appropriate amount of carbon and nitrogen coating, which induced a high mobility of electrons and larger crystallite size due to the insertion of fluoride to the spinel-type structure of Li4Ti5O12, enhancing lithium-ion transfer during the insertion/extraction process.


2022 ◽  
Vol 890 ◽  
pp. 161763
Author(s):  
Riki Kataoka ◽  
Toshikatsu Kojima ◽  
Mitsunori Kitta ◽  
Akihiko Machida

Nanomaterials ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 107
Author(s):  
Thomas Dippong

In recent years, nanosized spinel-type ferrites emerged as an important class of nanomaterials due to their high electrical resistivity, low eddy current loss, structural stability, large permeability at high frequency, high coercivity, high cubic magnetocrystalline anisotropy, good mechanical hardness, and chemical stability [...]


2021 ◽  
Vol 6 (48) ◽  
pp. 14019-14026
Author(s):  
Fei Zhang ◽  
Xinbo Zhu ◽  
Hanpeng Wu ◽  
Xiqiang Wu ◽  
Zijian Zhou ◽  
...  

Author(s):  
Jing Zhao ◽  
Pengfei Xiao ◽  
Shuang Han ◽  
Musajan Zulhumar ◽  
Dedong Wu

Abstract The magnetic CuFe2O4 nanoparticles were successfully synthesized with a coprecipitation method at 500 °C calcination temperature, which were utilized to degrade levofloxacin (LEV) as peroxymonosulfate (PMS) activator. The structure and composition of nanocatalyst were characterized by a series of methods, including Scanning electron microscopy, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, X-ray diffraction, Vibrating sample magnetometer and Thermogravimetric analysis. The effect of the PMS concentration, the catalyst dosage, the LEV initial concentration, the pH value and the inorganic anions on the LEV degradation was also explored. The results revealed that the designed CuFe2O4/PMS system had high activity and excellent stability in the complex conditions. The degradation efficiency of LEV still reached above 80% after four recycles of CuFe2O4 catalyst. The reactive species quenching experiments and electron paramagnetic resonance analysis suggested the existence of superoxide radicals, single oxygen, hydroxy radicals and sulfate radicals, and the first two were dominant radical oxygen species. Based on the mechanism analyses, the efficient degradation of LEV was probably due to the continuous generation of reactive species under the condition of Fe (III)/Fe (II) and Cu (II)/Cu (I) redox cycles. The research provided a reasonable reference for the PMS activation mechanism based spinel-type ferrite catalysis.


2021 ◽  
Vol 22 ◽  
pp. 100593
Author(s):  
H.J. Gao ◽  
S.F. Wang ◽  
L.M. Fang ◽  
G.A. Sun ◽  
X.P. Chen ◽  
...  
Keyword(s):  

Catalysts ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1476
Author(s):  
Vasyl Mykhailovych ◽  
Andrii Kanak ◽  
Ştefana Cojocaru ◽  
Elena-Daniela Chitoiu-Arsene ◽  
Mircea Nicolae Palamaru ◽  
...  

Spinel chromite nanoparticles are prospective candidates for a variety of applications from catalysis to depollution. In this work, we used a sol–gel auto-combustion method to synthesize spinel-type MgCr2O4 nanoparticles by using fructose (FS), tartaric acid (TA), and hexamethylenetetramine (HMTA) as chelating/fuel agents. The optimal temperature treatment for the formation of impurity-free MgCr2O4 nanostructures was found to range from 500 to 750 °C. Fourier transform infrared (FTIR) spectroscopy was used to determine the lattice vibrations of the corresponding chemical bonds from octahedral and tetrahedral positions, and the optical band gap was calculated from UV–VIS spectrophotometry. The stabilization of the spinel phase was proved by X-ray diffraction (XRD) and energy-dispersive X-ray (EDX) analysis. From field-emission scanning electron microscopy (FE-SEM), we found that the size of the constituent particles ranged from 10 to 40 nm. The catalytic activity of the as-prepared MgCr2O4 nanocrystals synthesized by using tartaric acid as a chelating/fuel agent was tested on the decomposition of hydrogen peroxide. In particular, we found that the nature of the chelating/fuel agent as well as the energy released during the auto-combustion played an important role on the structural, optical, and catalytic properties of MgCr2O4 nanoparticles obtained by this synthetic route.


2021 ◽  
Vol 66 (12) ◽  
pp. 1779-1784
Author(s):  
T. L. Simonenko ◽  
V. A. Bocharova ◽  
N. P. Simonenko ◽  
E. P. Simonenko ◽  
V. G. Sevastyanov ◽  
...  

Abstract—The synthesis of NiMoO4 hierarchical nanostructures using the hydrothermal method has been studied. The decomposition of NiMoO4·xH2O crystalline hydrate formed during the synthesis has been studied using synchronous thermal analysis upon heating in a stream of air and argon. According to X-ray diffraction as well as scanning and transmission electron microscopies, the proposed conditions allow one to synthesize single-phase nanosized (average CSR size of about 25 ± 2 nm) nickel(II) molybdate, which has a spinel-type monoclinic structure (space group C2/m) without impurity inclusions.


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