MAGNETIC CLUSTERS DEVELOPMENT IN OXIDIZED CeNi5 POWDER

Synthesis, X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy and magnetic measurements at low temperature of Ni metallic clusters covered by NiO , Ce 2 O 3 and CeO 2, obtained from CeNi 5 powder oxidized in air at different temperatures up to 800°C, are reported. The average crystallite size of Ni core and the thickness of NiO oxide formed at the surface increase with temperature due to recrystallization processes, from 34 nm at 300°C to 77 nm at 800°C and from 9 nm to 19 nm, respectively. Ni metallic component was detected both in XPS valence bands and core levels spectra only after sputtering. The hysteresis loop presents a small shift towards negative magnetic fields which confirms the presence of ferromagnetic Ni /antiferromagnetic NiO interfaces.

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Magnetic cluster developement in In1−x MnxSb semiconductor alloys

Open Physics ◽

10.2478/s11534-009-0140-7 ◽

2010 ◽

Vol 8 (4) ◽

Cited By ~ 7

Author(s):

Lidia Rednic ◽

Iosif Deac ◽

Eugen Dorolti ◽

Marin Coldea ◽

Vasile Rednic ◽

...

Keyword(s):

Magnetic Field ◽

Electron Microscopy ◽

Photoelectron Spectroscopy ◽

Magnetic Measurements ◽

Semiconductor Alloys ◽

X Ray Diffraction ◽

Magnetic Cluster ◽

X Ray ◽

Small Magnetic Field ◽

Transmission Electron

AbstractX-ray Diffraction (XRD), X-ray Photoelectron Spectroscopy (XPS), Transmission Electron Microscopy (TEM) and magnetic measurements as a function of applied magnetic field and temperature for In1−x MnxSb (0.05≤x≤0.2) system are reported. Magnetic measurements performed at high and small magnetic field in ZFC and FC indicate the coexistence of ferromagnetic In1−x MnxSb solid solution and two types of magnetic cluster: ferromagnetic MnSb and ferrimagnetic Mn2Sb. XPS valence band and Mn 2p core level spectra have confirmed the presence of MnSb and Mn2Sb phases. TEM images show some manganese antimonide phase microinclusions with dimension between (30–40) nm.

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Chemical Solution Deposition of YBCO Films with Gd Excess

Coatings ◽

10.3390/coatings10090860 ◽

2020 ◽

Vol 10 (9) ◽

pp. 860

Author(s):

Valentina Pinto ◽

Angelo Vannozzi ◽

Achille Angrisani Armenio ◽

Francesco Rizzo ◽

Andrea Masi ◽

...

Keyword(s):

Photoelectron Spectroscopy ◽

Chemical Solution Deposition ◽

Zero Field ◽

Chemical Solution ◽

Solution Deposition ◽

Decomposition Approach ◽

X Ray ◽

Transmission Electron ◽

Different Temperatures ◽

Metal Organic

Chemical solution deposition of Gd-doped YBCO, Y1GdyBa2Cu3O7−δ, (YBCO-Gd), film was carried out following the metal-organic decomposition approach and in situ route. Two dopant concentrations, 5 and 10 mol %, were evaluated. The morphology and crystalline structure of the superconductor films were deeply investigated. In general, a homogeneous and well c-axis oriented film was observed by using scanning and transmission electron microscopy (SEM and TEM) and X-ray diffraction. However, compared to pure YBCO, YBCO-Gd samples showed an increased stacking faults concentration, as recognized by TEM. X-ray photoelectron spectroscopy allowed studying the Gd distribution in the films and gathered information about the Gd electronic environment. Superconducting properties were evaluated at different temperatures, magnetic field directions, and intensities. Higher zero-field critical current densities were measured with respect to undoped samples in the temperature range from 10 to 77 K with both Gd concentrations (i.e., 28, 27, and 13 MA·cm−2, respectively, for YBCO-Gd 5%, YBCO-Gd 10%, and undoped YBCO at 10 K in self field condition). At low temperatures, this improvement was maintained up to 12 T, confirming the efficacy of Gd addition for the enhancement of transport properties of YBCO film.

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Biochar-Supported FeS/Fe3O4 Composite for Catalyzed Fenton-Type Degradation of Ciprofloxacin

Catalysts ◽

10.3390/catal9121062 ◽

2019 ◽

Vol 9 (12) ◽

pp. 1062 ◽

Cited By ~ 5

Author(s):

Yue Wang ◽

Xiaoxiao Zhu ◽

Dongqing Feng ◽

Anthony K. Hodge ◽

Liujiang Hu ◽

...

Keyword(s):

Electron Microscopy ◽

Photoelectron Spectroscopy ◽

Iron Sulfide ◽

Magnetic Composite ◽

X Ray Diffraction ◽

X Ray ◽

Transmission Electron ◽

Magnetite Fe3o4 ◽

Different Temperatures ◽

Cost Efficient

The Fenton-type oxidation catalyzed by iron minerals is a cost-efficient and environment-friendly technology for the degradation of organic pollutants in water, but their catalytic activity needs to be enhanced. In this work, a novel biochar-supported composite containing both iron sulfide and iron oxide was prepared, and used for catalytic degradation of the antibiotic ciprofloxacin through Fenton-type reactions. Dispersion of FeS/Fe3O4 nanoparticles was observed with scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS) and transmission electron microscopy (TEM). Formation of ferrous sulfide (FeS) and magnetite (Fe3O4) in the composite was validated by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). Ciprofloxacin (initial concentration = 20 mg/L) was completely degraded within 45 min in the system catalyzed by this biochar-supported magnetic composite at a dosage of 1.0 g/L. Hydroxyl radicals (·OH) were proved to be the major reactive species contributing to the degradation reaction. The biochar increased the production of ·OH, but decreased the consumption of H2O2, and helped transform Fe3+ into Fe2+, according to the comparison studies using the unsupported FeS/Fe3O4 as the catalyst. All the three biochars prepared by pyrolysis at different temperatures (400, 500 and 600 °C) were capable for enhancing the reactivity of the iron compound catalyst.

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Structural Optical Magnetic And Photocatalytic Properties of Ferromagnetic P-Type NiO: N-Type ZnO Nanocomposites

10.21203/rs.3.rs-1117627/v1 ◽

2021 ◽

Author(s):

G. Kavitha ◽

K. Thanigai Arul ◽

Manikandan Elayaperumal

Keyword(s):

Average Crystallite Size ◽

Xrd Analysis ◽

Ferromagnetic Behavior ◽

Chemical Route ◽

X Ray ◽

Transmission Electron ◽

Scanning Transmission ◽

Different Temperatures ◽

Conducting Metal Oxides ◽

P Type

Abstract The semiconductor-transition conducting metal oxides (p-type NiO: n-type ZnO) nanocomposites (NCs) called (NZO) are successfully prepared by a simple wet-chemical route followed by the systematic sintering at different temperatures such as 400°C, 500°C, 600°C, and 700 °C. The structure and morphology of the samples were characterized by X-ray diffraction (XRD), high-resolution scanning/transmission electron microscopy (HR-SEM/TEM), and energy-dispersive X-ray spectrometry (EDX) techniques. XRD analysis reveals that the average crystallite size of the NZO NCs was found to be in the range 16-18 nm. The synthesized sample discloses a ferromagnetic behavior. The photocatalytic degradation of rhodamine B in an aqueous solution was superior at the NZO NC at 600 °C in comparison with other samples. Here, the NZO NCs display to be good candidates for magnetic and photocatalytic application.

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Study on the nature of the electrochemically synthesized hard Fe–15.4 mass% Ni–0.70 mass% C alloy film

Journal of Materials Research ◽

10.1557/jmr.2003.0115 ◽

2003 ◽

Vol 18 (4) ◽

pp. 840-847

Author(s):

A. S. M. A. Haseeb ◽

Y. Hayashi ◽

M. Masuda ◽

M. Arita

Keyword(s):

Electron Microscopy ◽

Photoelectron Spectroscopy ◽

Magnetic Measurements ◽

Alloy Film ◽

The State ◽

Scanning Calorimetry ◽

X Ray ◽

Transmission Electron ◽

Electrochemically Deposited ◽

Decomposition Behavior

Electrochemical synthesis of hard Fe–15.4 mass% Ni–0.70 mass% C alloy film with a hardness 750 HV was carried out from sulfate-based bath containing a small amount of citric acid and L-ascorbic acid. The nature of the alloy was investigated by different characterization techniques including x-ray diffraction, x-ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscopy, Mössbauer spectroscopy, differential scanning calorimetry, and magnetic measurements. The decomposition behavior of the alloy was also studied and compared with that of thermally prepared martensite. It was found that the electrochemically deposited Fe–Ni–C alloy exists in a state that is ahead of the freshly quenched state of martensite. It is suggested that the state of the electrochemically deposited Fe–15.4 mass% Ni–0.70 mass% C alloy corresponds to the state of thermal martensite, which had been heated to the preprecipitation stage of tempering.

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A STUDY ON THE PRECIPITATION OF Ge-RICH NANOPARTICLES IN A LUMINESCENT (Er, Ge) CO-DOPED SiO2 FILM SPUTTERED WITH Ar + O2 PLASMA

International Journal of Nanoscience ◽

10.1142/s0219581x06004681 ◽

2006 ◽

Vol 05 (04n05) ◽

pp. 493-498

Author(s):

C. L. HENG ◽

Y. J. LI ◽

J. MAYANDI ◽

T. G. FINSTAD ◽

S. JØRGENSEN ◽

...

Keyword(s):

Photoelectron Spectroscopy ◽

Annealing Temperature ◽

Rf Magnetron Sputtering ◽

Sio2 Film ◽

X Ray ◽

Transmission Electron ◽

Different Temperatures ◽

Diffraction Patterns ◽

Amorphous States ◽

Co Doped

We report the photoluminescence (PL) from an ( Er , Ge ) co-doped SiO 2 film deposited by rf-magnetron sputtering in an Ar + O 2 ambience. The sample film was annealed in N 2 for 30 min at different temperatures. The PL intensity increases as the annealing temperature increases from 700 to 1000°C, and drops to very weak after 1100°C annealing. High-resolution transmission electron microscopy (TEM) observation shows that there are some Ge -rich nanoparticles precipitated after 700°C annealing, and more clusters precipitated after 1000°C annealing. However, no Ge nanocrystals were found in these films, the diffraction patterns are always halo which indicates that the precipitated clusters are in amorphous states. X-ray photoelectron spectroscopy (XPS) analysis indicates the Ge in the nanoclusters is mostly in an oxidized state and the oxidation state of Er increases with increasing annealing temperature.

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α-Cellulose Fibers of Paper-Waste Origin Surface-Modified with Fe3O4 and Thiolated-Chitosan for Efficacious Immobilization of Laccase

Polymers ◽

10.3390/polym13040581 ◽

2021 ◽

Vol 13 (4) ◽

pp. 581

Author(s):

Gajanan S. Ghodake ◽

Surendra K. Shinde ◽

Ganesh D. Saratale ◽

Rijuta G. Saratale ◽

Min Kim ◽

...

Keyword(s):

Enzyme Immobilization ◽

Photoelectron Spectroscopy ◽

Cellulose Fibers ◽

Relative Activity ◽

Significant Activity ◽

X Ray Diffraction ◽

X Ray ◽

Transmission Electron ◽

Laccase Immobilization ◽

Surface Modified

The utilization of waste-paper-biomass for extraction of important α-cellulose biopolymer, and modification of extracted α-cellulose for application in enzyme immobilization can be extremely vital for green circular bio-economy. Thus, in this study, α-cellulose fibers were super-magnetized (Fe3O4), grafted with chitosan (CTNs), and thiol (-SH) modified for laccase immobilization. The developed material was characterized by high-resolution transmission electron microscopy (HR-TEM), HR-TEM energy dispersive X-ray spectroscopy (HR-TEM-EDS), X-ray diffraction (XRD), vibrating sample magnetometer (VSM), X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared spectroscopy (FT-IR) analyses. Laccase immobilized on α-Cellulose-Fe3O4-CTNs (α-Cellulose-Fe3O4-CTNs-Laccase) gave significant activity recovery (99.16%) and laccase loading potential (169.36 mg/g). The α-Cellulose-Fe3O4-CTNs-Laccase displayed excellent stabilities for temperature, pH, and storage time. The α-Cellulose-Fe3O4-CTNs-Laccase applied in repeated cycles shown remarkable consistency of activity retention for 10 cycles. After the 10th cycle, α-Cellulose-Fe3O4-CTNs possessed 80.65% relative activity. Furthermore, α-Cellulose-Fe3O4-CTNs-Laccase shown excellent degradation of pharmaceutical contaminant sulfamethoxazole (SMX). The SMX degradation by α-Cellulose-Fe3O4-CTNs-Laccase was found optimum at incubation time (20 h), pH (3), temperatures (30 °C), and shaking conditions (200 rpm). Finally, α-Cellulose-Fe3O4-CTNs-Laccase gave repeated degradation of SMX. Thus, this study presents a novel, waste-derived, highly capable, and super-magnetic nanocomposite for enzyme immobilization applications.

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Novel Carbon Dots Derived from Glycyrrhizae Radix et Rhizoma and Their Anti-Gastric Ulcer Effect

Molecules ◽

10.3390/molecules26061512 ◽

2021 ◽

Vol 26 (6) ◽

pp. 1512

Author(s):

Yuhan Liu ◽

Meiling Zhang ◽

Jinjun Cheng ◽

Yue Zhang ◽

Hui Kong ◽

...

Keyword(s):

Gastric Ulcer ◽

Photoelectron Spectroscopy ◽

Carbon Dots ◽

High Performance ◽

Raw264.7 Cells ◽

Mice Model ◽

X Ray ◽

Glycyrrhizae Radix ◽

Transmission Electron ◽

High Resolution Tem

Glycyrrhizae Radix et Rhizoma (GRR) is one of the commonly used traditional Chinese medicines in clinical practice, which has been applied to treat digestive system diseases for hundreds of years. GRR is preferred for anti-gastric ulcer, however, the main active compounds are still unknown. In this study, GRR was used as precursor to synthesize carbon dots (CDs) by a environment-friendly one-step pyrolysis process. GRR-CDs were characterized by using transmission electron microscopy, high-resolution TEM, fourier transform infrared, ultraviolet-visible and fluorescence spectroscopy, X-ray photoelectron spectroscopy, X-ray diffraction and high-performance liquid chromatography. In addition, cellular toxicity of GRR-CDs was studied by using CCK-8 in RAW264.7 cells, and the anti-gastric ulcer activity was evaluated and confirmed using mice model of acute alcoholic gastric ulcer. The experiment confirmed that GRR-CDs were the spherical structure with a large number of active groups on the surface and their particle size ranged from 2 to 10 nm. GRR-CDs had no toxicity to RAW264.7 cells at concentration of 19.5 to 5000 μg/mL and could reduce the oxidative damage of gastric mucosa and tissues caused by alcohol, as demonstrated by restoring expression of malondialdehyde, superoxide dismutase and nitric oxide in serum and tissue of mice. The results indicated the explicit anti-ulcer activity of GRR-CDs, which provided a new insights for the research on effective material basis of GRR.

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Highly active carbon nanotube–promoted Rh-Mn-Li/SiO2 catalysts for the synthesis of C2+ oxygenates from syngas

Journal of Chemical Research ◽

10.1177/1747519820984728 ◽

2021 ◽

pp. 174751982098472

Author(s):

Jun Yu ◽

Ying Han ◽

Guoqing Chen ◽

Xiuzhen Xiao ◽

Haifang Mao ◽

...

Keyword(s):

Carbon Nanotubes ◽

Photoelectron Spectroscopy ◽

Co Hydrogenation ◽

X Ray ◽

Highly Active ◽

Transmission Electron ◽

Co Insertion ◽

Temperature Programmed Surface Reaction ◽

Temperature Programmed ◽

Oxygenate Synthesis

The effect of carbon nanotubes on the catalytic properties of Rh-Mn-Li/SiO2 catalysts was investigated for CO hydrogenation. The catalysts were comprehensively characterized by means of X-ray power diffraction, N2 sorption, transmission electron microscope, H2–temperature-programmed reduction, CO–temperature-programmed desorption, temperature-programmed surface reaction, and X-ray photoelectron spectroscopy. The results showed that an appropriate amount of carbon nanotubes can be attached to the surface of the SiO2 sphere and can improve the Rh dispersion. Moderate Rh-Mn interaction can be obtained by doping with the appropriate amount of carbon nanotubes, which promotes the formation of strongly adsorbed CO and facilitates the progress of CO insertion, resulting in the increase in the selectivity of C2+ oxygenate synthesis.

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Effect of calcination temperature on rare earth tailing catalysts for catalytic methane combustion

Green Processing and Synthesis ◽

10.1515/gps-2020-0053 ◽

2020 ◽

Vol 9 (1) ◽

pp. 734-743

Author(s):

Ran Zhao ◽

ZiChen Tian ◽

Zengwu Zhao

Keyword(s):

Rare Earth ◽

Mine Tailings ◽

Photoelectron Spectroscopy ◽

Methane Combustion ◽

Space Velocity ◽

High Catalytic Activity ◽

Reduction Peak ◽

X Ray ◽

Different Temperatures ◽

Bayan Obo

AbstractBayan Obo tailings are rich in rare earth elements (REEs), iron, and other catalytic active substances. In this study, mine tailings were calcined at different temperatures and tested for the catalytic combustion of low-concentration methane. Upon calcination at 600°C, high catalytic activity was revealed, with 50% CH4 conversion at 587°C (space velocity of 12,000 mL/g h). The physicochemical properties of catalysts were characterized using thermogravimetric analysis, X-ray diffraction, scanning electron microscopy, hydrogen temperature-programmed reduction (H2-TPR), and X-ray photoelectron spectroscopy (XPS). Compared to the raw ore sample, the diffraction peak intensity of Fe2O3 increased post calcination, whereas that of CeCO3F decreased. A porous structure appeared after the catalyst was calcined at 600°C. Additionally, Fe, Ce, Ti, and other metal elements were more highly dispersed on the catalyst surface. H2-TPR results revealed a broadening of the reduction temperature range for the catalyst calcined at 600°C and an increase in the reduction peak. XPS analysis indicated the presence of Ce in the form of Ce3+ and Ce4+ oxidation states and the coexistence of Fe in the form of Fe2+ and Fe3+. Moreover, XPS revealed a higher surface Oads/Olatt ratio. This study provides evidence for the green reuse of Bayan Obo mine tailings in secondary resources.

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