scholarly journals Synthesis of Metal Nanoparticles by Microorganisms

Crystals ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 589 ◽  
Author(s):  
Yugo Kato ◽  
Michio Suzuki
Keyword(s):  
Metal Nanoparticles ◽  
Photoelectron Spectroscopy ◽  
Energy Efficient ◽  
Room Temperature ◽  
Molecular Mechanisms ◽  
Green Energy ◽  
X Ray Diffraction ◽  
X Ray ◽  
Low Toxicity ◽  
Temperature And Pressure

Metal nanoparticles (NPs), with sizes ranging from 1–100 nm, are of great scientific interest because their functions and features differ greatly from those of bulk metal. Chemical or physical methods are used to synthesize commercial quantities of NPs, and green, energy-efficient approaches generating byproducts of low toxicity are desirable to minimize the environmental impact of the industrial methods. Some microorganisms synthesize metal NPs for detoxification and metabolic reasons at room temperature and pressure in aqueous solution. Metal NPs have been prepared via green methods by incubating microorganisms or cell-free extracts of microorganisms with dissolved metal ions for hours or days. Metal NPs are analyzed using various techniques, such as ultraviolet-visible spectroscopy, electron microscopy, X-ray diffraction, electron diffraction, energy-dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy. Numerous publications have focused on microorganisms that synthesize various metal NPs. For example, Ag, Au, CdS, CdSe, Cu, CuO, Gd2O3, Fe3O4, PbS, Pd, Sb2O3, TiO2, and ZrO2 NPs have been reported. Herein, we review the synthesis of metal NPs by microorganisms. Although the molecular mechanisms of their synthesis have been investigated to some extent, experimental evidence for the mechanisms is limited. Understanding the mechanisms is crucial for industrial-scale development of microorganism-synthesized metal NPs.

A Mild and Efficient Approach for the Reduction of Graphene Oxide

2013 ◽  
Vol 652-654 ◽  
pp. 206-209
Author(s):  
Yu Feng Wang ◽  
Chun Hua Han ◽  
Bao Liu ◽  
Dong Mei Zhao ◽  
Dong Yu Zhao ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Photoelectron Spectroscopy ◽  
Room Temperature ◽  
X Ray Diffraction ◽  
X Ray ◽  
Efficient Approach ◽  
Low Toxicity

A mild and efficient approach for the reduction of graphene oxide by NaHTe is reported in this work. This reductant is of low toxicity and nonvolatile and it reduce GO to graphene at room temperature in 2h. X-ray diffraction results showed that NaHTe can reduce GO completely in shorter time, comparing with hydroxylamine. Furthermore, X-ray photoelectron spectroscopy also indicates the reduction of GO to grapheme.

scholarly journals Synthesis of Magnetic Ferrocene-Containing Polymer with Photothermal Effects for Rapid Degradation of Methylene Blue

Polymers ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 558
Author(s):  
Wenhui Zhu ◽  
Caiyun Zhang ◽  
Yali Chen ◽  
Qiliang Deng
Keyword(s):  
Methylene Blue ◽  
Photoelectron Spectroscopy ◽  
Room Temperature ◽  
Degradation Rate ◽  
Model Compound ◽  
Vibrating Sample Magnetometer ◽  
Simulated Sunlight ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ft Ir

Photothermal materials are attracting more and more attention. In this research, we synthesized a ferrocene-containing polymer with magnetism and photothermal properties. The resulting polymer was characterized by Fourier-transform infrared (FT-IR), vibrating sample magnetometer (VSM), scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and thermogravimetric analysis (TGA). Its photo-thermocatalytic activity was investigated by choosing methylene blue (MB) as a model compound. The degradation percent of MB under an irradiated 808 nm laser reaches 99.5% within 15 min, and the degradation rate is 0.5517 min−1, which is 145 times more than that of room temperature degradation. Under irradiation with simulated sunlight, the degradation rate is 0.0092 min−1, which is approximately 2.5 times more than that of room temperature degradation. The present study may open up a feasible route to degrade organic pollutants.

ROOM TEMPERATURE PHOTOLUMINESCENCE OF POLYCRYSTALLINE SIC PREPARED FROM CARBON-SATURATED SI MELT

2002 ◽  
Vol 16 (06n07) ◽  
pp. 1047-1051
Author(s):  
JIANPING MA ◽  
ZHIMING CHEN ◽  
GANG LU ◽  
MINGBIN YU ◽  
LIANMAO HANG ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Photoelectron Spectroscopy ◽  
Room Temperature ◽  
Uv Light ◽  
X Ray Diffraction ◽  
X Ray ◽  
Room Temperature Photoluminescence ◽  
Composition And Structure ◽  
Light Excitation ◽  
Scanning Electron

Intense photoluminescence (PL) has been observed at room temperature from the polycrystalline SiC samples prepared from carbon-saturated Si melt at a temperature ranging from 1500 to 1650°C. Composition and structure of the samples have been confirmed by means of X-ray photoelectron spectroscopy, X-ray diffraction and scanning electron microscopy. PL measurements with 325 nm UV light excitation revealed that the room temperature PL spectrum of the samples consists of 3 luminescent bands, the peak energies of which are 2.38 eV, 2.77 eV and 3.06 eV, respectively. The 2.38 eV band is much stronger than the others. It is suggested that some extrinsic PL mechanisms associated with defect or interface states would be responsible to the intensive PL observed at room temperature.

XRD and XPS studies of room temperature spontaneous interfacial reaction of CeO2 thin films on Si and Si3N4 substrates

RSC Advances ◽  
2014 ◽  
Vol 4 (108) ◽  
pp. 62935-62939 ◽  
Author(s):  
Parthasarathi Bera ◽  
Chinnasamy Anandan
Keyword(s):  
Thin Films ◽  
Interfacial Reaction ◽  
Photoelectron Spectroscopy ◽  
Room Temperature ◽  
Interfacial Reactions ◽  
X Ray Diffraction ◽  
X Ray

X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) investigations of interfacial reactions between Ce and Si have been carried out on as-deposited and 15 month aged CeO2/Si and CeO2/Si3N4 thin films.

scholarly journals Room-Temperature Formation of Hard BCx Films by Low Power Magnetron Sputtering

2021 ◽  
Vol 11 (21) ◽  
pp. 9896
Author(s):  
Veronica Sulyaeva ◽  
Maxim Khomyakov ◽  
Marina Kosinova
Keyword(s):  
Magnetron Sputtering ◽  
Photoelectron Spectroscopy ◽  
Room Temperature ◽  
X Ray Diffraction ◽  
Film Properties ◽  
X Ray ◽  
Sputtering Power ◽  
Chemical States ◽  
Rf Signal ◽  
Dual Target

Boron carbide is one of the most important non-metallic materials. Amorphous BCx films were synthesized at room temperature by single- and dual-target magnetron sputtering processes. A B4C target and C target were operated using an RF signal and a DC signal, respectively. The effect of using single- and dual-target deposition and process parameters on the chemical bonding and composition of the films as well as their functional properties were characterized by Fourier transform infrared spectroscopy, Raman spectroscopy, X-ray photoelectron spectroscopy, X-ray energy dispersive analysis, X-ray diffraction, ellipsometry, and spectrophotometry. It was found that the film properties depend on the sputtering power and the used targets. EDX data show that the composition of the samples varied from B2C to practically BC2 in the case of using an additional C target. According to the XPS data, it corresponds to the different chemical states of the boron atom. A nanoindentation study showed that the film with a composition close to B2C deposited with the highest B4C target power reached a hardness of 25 GPa and Young’s modulus of 230 GPa. The optical properties of the films also depend on the composition, so the band gap (Eg) of the BCx film varied in the range of 2.1–2.8 eV, while the Eg of the carbon-rich films decreased to 1.1 eV.

scholarly journals SYNTHESIS AND ANTIDEPRESSANT ACTIVITY OF 2-BROMO-1-(THIETAN-3-YL) IMIDAZOLE-4, 5-DICARBOXYLIC ACID DERIVATIVES

2017 ◽  
Vol 9 (8) ◽  
pp. 154
Author(s):  
Ferkat Khaliullin ◽  
Irina Nikitina ◽  
Irina Nikitina ◽  
Anfisa Valieva ◽  
Anfisa Valieva ◽  
...  
Keyword(s):  
Locomotor Activity ◽  
Dicarboxylic Acid ◽  
Room Temperature ◽  
Antidepressant Activity ◽  
Tail Suspension ◽  
X Ray Diffraction ◽  
Melting Points ◽  
X Ray ◽  
Single Intraperitoneal Injection ◽  
Low Toxicity

Objective: Synthesis of the salts and diylidenehydrazidеs of 2-bromo-1-(thietan-3-yl) imidazole-4,5-dicarboxylic acid to evaluate the antidepressant activities.Methods: The structures of the synthesised compounds were confirmed by elemental analysis and 1Н NMR spectral data. The melting points of the compounds were determined on a Stuart SMP30 apparatus. The X-ray diffraction data for compound IIc were obtained at room temperature on a Xcalibur Gemini Еos. The antidepressant activity was investigated in the tail suspension and forced swimming tests. The locomotor activity and anxiety were studied in the open field test.Results: All synthesised compounds showed antidepressant activity after single intraperitoneal injection to male mice at doses equimolar to 10 mg/kg of imipramine. One of the compounds, 2-bromo-1-(thietan-3-yl) imidazole-4,5-dicarboxylic acid di[(4-hydroxy-3-methoxyphenyl) methylidenehydrazide], reduced the anxiety and decreased the locomotor activity at statistically significant levels. Other compounds did not have sedative and/or stimulating effects.Conclusion: Among the synthesised 2-bromo-1-(thietan-3-yl) imidazole-4,5-dicarboxylic acid derivatives, compounds with marked antidepressant activity were identified. An obvious advantage of these products is low toxicity.

scholarly journals Magnetic and electronic properties of M-Ba–Cu–O (M = Y, Er, Eu)

1987 ◽  
Vol 2 (6) ◽  
pp. 775-778 ◽  
Author(s):  
H. Jenny ◽  
B. Walz ◽  
G. Leeman ◽  
V. Geiser ◽  
S. Jost ◽  
...  
Keyword(s):  
Electrical Resistivity ◽  
Photoelectron Spectroscopy ◽  
Room Temperature ◽  
Single Phase ◽  
Liquid Nitrogen Temperature ◽  
Solid State Reaction Method ◽  
X Ray Diffraction ◽  
Reaction Method ◽  
X Ray ◽  
Diffraction Peaks

Various high-Tc superconductors of the La–(Ba,Sr)–Cu–O and the M–Ba–Cu–O systems with M = Y, Er, and Eu have been prepared by the solid-state reaction method. Single-phase samples with no additional diffraction peaks as verified by x-ray diffraction (XRD) measurements have been obtained. Measurements of the electrical resistivity and of the magnetization showed sharp superconducting transitions with a width of 1 K. The measurements of the magnetic susceptibility have been extended above room temperature up to 770 K. There is clear evidence for the formation of a magnetic moment in all M–Ba–Cu–O samples. Monochromated x-ray photoelectron spectroscopy (MXPS) valence band and x-ray photoelectron spectroscopy (XPS) core level spectra have been measured on various samples at room temperature and at liquid nitrogen temperature.

FERROMAGNETISM IN Fe-DOPED ZnO THIN FILMS

2009 ◽  
Vol 23 (06) ◽  
pp. 815-824 ◽  
Author(s):  
R. B. ZHAO ◽  
D. L. HOU ◽  
Y. Y. WEI ◽  
Z. Z. ZHOU ◽  
C. F. PAN ◽  
...  
Keyword(s):  
Thin Films ◽  
Photoelectron Spectroscopy ◽  
Exchange Coupling ◽  
Room Temperature ◽  
Room Temperature Ferromagnetism ◽  
X Ray Diffraction ◽  
Axis Orientation ◽  
X Ray ◽  
Si Substrates ◽  
Fe Ions

Zn 1-x Fe x O (x = 0.04, 0.06, 0.08, 0.10, 0.12) thin films were grown on Si substrates using reactive magnetron sputtering. X-ray diffraction analyses show that the samples have wurtzite structures with the c-axis orientation. X-ray photoelectron spectroscopy results indicate that the Fe ions are in a +2 charge state in the films. Magnetization measurements indicate that room temperature ferromagnetism is present in films annealed in vacuum while films annealed in air were non-magnetic. The presence of oxygen vacancies in these films may mediate exchange coupling of the dopant ions, resulting in room temperature ferromagnetism.

scholarly journals Magnetic Au-Ag-γ-Fe2O3/rGO Nanocomposites as an Efficient Catalyst for the Reduction of 4-Nitrophenol

Nanomaterials ◽  
2018 ◽  
Vol 8 (11) ◽  
pp. 877 ◽  
Author(s):  
Guangyu Lei ◽  
Jingwen Ma ◽  
Zhen Li ◽  
Xiaobin Fan ◽  
Wenchao Peng ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Room Temperature ◽  
Catalytic Performance ◽  
Reduction Reaction ◽  
X Ray Diffraction ◽  
Efficient Catalyst ◽  
Reaction Systems ◽  
X Ray ◽  
Transmission Electron ◽  
The Impact

In this paper, a facile route has been developed to prepare magnetic trimetallic Au-Ag-γ-Fe2O3/rGO nanocomposites. The impact of the preparation method (the intensity of reductant) on the catalytic performance was investigated. The nanocomposites were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The prepared nanocomposites show fine catalytic activity towards the reduction reaction of 4-nitrophenol (4-NP). The nanocomposites also have superparamagnetism at room temperature, which can be easily separated from the reaction systems by applying an external magnetic field.

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