scholarly journals Simple Synthesis and Luminescence Characteristics of PVP-Capped GeO2Nanoparticles

2011 ◽  
Vol 2011 ◽  
pp. 1-5 ◽  
Author(s):  
Wei Wu ◽  
Xu Zou ◽  
Quanjun Li ◽  
Bingbing Liu ◽  
Bo Liu ◽  
...  
Keyword(s):  
Surface Defects ◽  
Hydrothermal Process ◽  
Thermo Gravimetric Analysis ◽  
Gravimetric Analysis ◽  
X Ray Diffraction ◽  
Electron Hole ◽  
Transmission Electron ◽  
Luminescence Characteristics ◽  
Facile Hydrothermal Process ◽  
Hole Recombination

Polyvinylpyrrolidone (PVP)-capped rutile GeO2nanoparticles were synthesized through a facile hydrothermal process. The obtained nanoparticles were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), thermo gravimetric analysis (TGA), and photoluminescence spectroscopy (PL). The capped GeO2nanoparticles showed significantly enhanced luminescence properties compared with those of the uncapped ones. We attributed this result to the effect of reducing surface defects and enhancing the possibility of electron-hole recombination of the GeO2nanoparticles by the PVP molecules. PVP-capped GeO2nanoparticles have potential application in optical and electronic fields.

scholarly journals Enhanced Photocatalytic Activity of Cu2O Cabbage/RGO Nanocomposites under Visible Light Irradiation

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1712
Author(s):  
Appusamy Muthukrishnaraj ◽  
Salma Ahmed Al-Zahrani ◽  
Ahmed Al Otaibi ◽  
Semmedu Selvaraj Kalaivani ◽  
Ayyar Manikandan ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Thermo Gravimetric Analysis ◽  
Visible Region ◽  
Catalytic Performance ◽  
Precipitation Method ◽  
Gravimetric Analysis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Dye Pollutants ◽  
Transmission Electron

Towards the utilization of Cu2O nanomaterial for the degradation of industrial dye pollutants such as methylene blue and methyl orange, the graphene-incorporated Cu2O nanocomposites (GCC) were developed via a precipitation method. Using Hummers method, the grapheme oxide (GO) was initially synthesized. The varying weight percentages (1–4 wt %) of GO was incorporated along with the precipitation of Cu2O catalyst. Various characterization techniques such as Fourier-transform infra-red (FT-IR), X-ray diffraction (XRD), UV–visible diffused reflectance (UV-DRS), Raman spectroscopy, thermo gravimetric analysis (TGA), energy-dispersive X-ray analysis (EDX), and electro chemical impedance (EIS) were followed for characterization. The cabbage-like morphology of the developed Cu2O and its composites were ascertained from field-emission scanning electron microscopy (FESEM) and high-resolution transmission electron microscopy (HR-TEM). In addition, the growth mechanism was also proposed. The results infer that 2 wt % GO-incorporated Cu2O composites shows the highest value of degradation efficiency (97.9% and 96.1%) for MB and MO at 160 and 220 min, respectively. Further, its catalytic performance over visible region (red shift) was also enhanced to an appreciable extent, when compared with that of other samples.

Effect of Synthesis Temperature on Particles Size and Morphology of Zirconium Oxide Nanoparticle

2017 ◽  
Vol 50 ◽  
pp. 18-31 ◽  
Author(s):  
Rudzani Sigwadi ◽  
Simon Dhlamini ◽  
Touhami Mokrani ◽  
Patrick Nonjola
Keyword(s):  
Electron Microscopy ◽  
Particle Size ◽  
Zirconium Oxide ◽  
Thermo Gravimetric Analysis ◽  
Gravimetric Analysis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Crystallite Sizes ◽  
Ft Ir

The paper presents the synthesis and investigation of zirconium oxide (ZrO2) nanoparticles that were synthesised by precipitation method with the effects of the temperatures of reaction on the particles size, morphology, crystallite sizes and stability at high temperature. The reaction temperature effect on the particle size, morphology, crystallite sizes and stabilized a higher temperature (tetragonal and cubic) phases was studied. Thermal decomposition, band structure and functional groups were analyzed by Brunauer-Emmett-Teller (BET), Scanning Electron Microscopy (SEM), Transmission electron microscopy (TEM), X-ray diffraction (XRD), Thermo-gravimetric analysis (TGA) and Fourier transform infrared (FT-IR). The crystal structure was determined using X-ray diffraction. The morphology and the particle size were studied using (SEM) and (TEM). The shaped particles were confirmed through the SEM analysis. The transmission electron microscopic analysis confirmed the formation of the nanoparticles with the particle size. The FT-IR spectra showed the strong presence of ZrO2 nanoparticles.

CeO2/TiO2 Nanotubes Composites: Synthesis, Characterization, and Photocatalytic Properties

2012 ◽  
Vol 583 ◽  
pp. 86-90 ◽  
Author(s):  
Hai Bin Li ◽  
Xin Yong Li ◽  
Yan De Song ◽  
Shu Guang Chen ◽  
Ying Wang ◽  
...  
Keyword(s):  
Diffuse Reflectance Spectroscopy ◽  
Atomic Ratio ◽  
X Ray Diffraction ◽  
Hydrothermal Route ◽  
Electron Hole ◽  
Calcination Process ◽  
X Ray ◽  
Transmission Electron ◽  
Hole Recombination

TiO2nanotubes were prepared via a hydrothermal route. CeO2nanoparticles with diameters around 5nm were loaded onto the surface of TiO2nanotubes via a deposition approach followed by a calcination process. Transmission electron microscopy (TEM), X-ray diffraction (XRD), and UV-vis diffuse reflectance spectroscopy (UV-vis) were applied for the characterization of the as-prepared CeO2/TiO2nanotubes composites. The results show that CeO2particles are highly dispersed on the surface of TiO2nanotubes. The TiO2 nanotubes are modified to response to the visible light due to the combination with CeO2. The CeO2/TiO2nanotubes composites with a CeO2/TiO2atomic ratio of 2.5% show a further improvement on the photocatalytic activity for degradation of Rhodamine B in water. The presence of CeO2improves the light absorption of TiO2nanotubes and inhibits the electron-hole recombination.

THE ASSEMBLY OF CHAIN-LIKE Ni ARRAYS UNDER MAGNETIC FIELD AND ITS ENHANCED PROPERTIES

2010 ◽  
Vol 09 (05) ◽  
pp. 543-547 ◽  
Author(s):  
JUN WANG ◽  
SHIHE CAO ◽  
SIHUA XIA ◽  
NING GAN
Keyword(s):  
Magnetic Field ◽  
Electron Microscope ◽  
External Magnetic Field ◽  
Self Assembly ◽  
Hydrothermal Process ◽  
X Ray Diffraction ◽  
Vertical Arrays ◽  
Transmission Electron ◽  
Xrd Patterns ◽  
Facile Hydrothermal Process

Chain-like nickel arrays assembled from magnetic Ni spheres were successfully prepared through a facile hydrothermal process at 200°C under a 0.25 T external magnetic field. The external magnetic field is strongly believed to be the driving force of the self-assembly. The sample was highly crystalline as confirmed by the X-ray diffraction (XRD) patterns. The scanning electron microscope (SEM) and transmission electron microscope (TEM) images show that all Ni spheres are closely interconnected to form chains, with ~ 950 nm in diameter and ~ 1 cm in length, which arrange into vertical arrays on the silicon substrate. The coercivity and remnant magnetization ratio of the sample, 670 Oe and 0.612, respectively, are substantially higher than for the sample prepared without an applied external magnetic field (68 Oe and 0.336). Such enhancements can be attributed to their novel superstructure, shape anisotropy, reduced demagnetization factor, etc. This process can be used to fabricate large arrays of uniform chains of magnetic materials and modulate their magnetic properties.

Synthesis, characterization of visible active MO hallow spheres by combustion technique

2018 ◽  
Vol 1 (3) ◽  
pp. 1-14
Author(s):  
G Thennarasu ◽  
A Sivasamy
Keyword(s):  
Electron Microscope ◽  
Diffuse Reflectance Spectroscopy ◽  
Thermo Gravimetric Analysis ◽  
Oxygen Demand ◽  
Gravimetric Analysis ◽  
X Ray Diffraction ◽  
Simple Method ◽  
Transmission Electron ◽  
Direct Blue ◽  
Combustion Technique

A simple method to synthesize nano-sized hallow sphere such as Zn-Ce metal oxide (MO) by combustion technique. The product was characterized by X-ray diffraction (XRD), Field emission-scanning electron microscope (FE-SEM), Fourier transform infrared spectroscopy (FT-IR), Thermo gravimetric analysis (TGA), Diffuse Reflectance Spectroscopy (DRS) and Transmission electron microscope (TEM). The photocatalytic activity of Zn-Ce MO nano-sized hallow sphere was examined by studying the degradation of direct blue 71 (DB71) under visible light irradiations in a slurry photoreactor. The effect of parameters such as the catalyst dosage, concentration of the dye, pH and kinetics on photocatalytic degradation of DB71 is also studied. Degradation of dye was confirmed by UV-VIS spectrum, chemical oxygen demand (COD) and ESI-Mass.

Preparation of α-Al2O3 Powders via Non-Hydrolytic Sol-Gel Method

2015 ◽  
Vol 1104 ◽  
pp. 3-8 ◽  
Author(s):  
Tong Qing Zhou ◽  
Ting Chen ◽  
Wei Hui Jiang ◽  
Jian Min Liu ◽  
Xiao Jun Zhang ◽  
...  
Keyword(s):  
Sol Gel ◽  
Thermo Gravimetric Analysis ◽  
Raw Material ◽  
Gravimetric Analysis ◽  
X Ray Diffraction ◽  
Thermo Gravimetric ◽  
X Ray ◽  
Corundum Structure ◽  
Transmission Electron ◽  
Peg 600

Corundum structurealumina (α-Al2O3) powders were prepared via a non-hydrolytic sol-gel (NHSG) method using aluminum as raw material, ethanol as solvent, and iodine as catalyst. X-ray diffraction (XRD), differential thermal analysis (DTA), thermo gravimetric analysis (TG) were used to characterize the crystal phase of the products, while scanning electron microscopy (SEM) and transmission electron microscope (TEM) were employed to analyze the morphology. The results indicated that γ-Al2O3 was completely changed to α-Al2O3 at 1100 o C with a bit of aggregation. When 3 wt.% polyethylene glycol 600 (PEG 600) was introduced on the NHSG process, the dispersion was improved and the particle size decreased to100 nm.

Nanocrystalline α–Fe, Fe3C, and Fe7C3 produced by CO2 laser pyrolysis

1993 ◽  
Vol 8 (7) ◽  
pp. 1666-1674 ◽  
Author(s):  
Xiang-Xin Bi ◽  
B. Ganguly ◽  
G.P. Huffman ◽  
F.E. Huggins ◽  
M. Endo ◽  
...  
Keyword(s):  
Thermo Gravimetric Analysis ◽  
Particle Surface ◽  
Pyrolytic Carbon ◽  
Gravimetric Analysis ◽  
X Ray Diffraction ◽  
Laser Pyrolysis ◽  
Transmission Electron ◽  
Synthesis Procedure ◽  
Vapor Mixtures ◽  
Spectroscopy Studies

Nanocrystalline α–Fe, Fe3C, and Fe7C3, particles with narrow size distributions were produced by CO2 laser pyrolysis of vapor mixtures of Fe(CO)5 and C2H4. Details of the synthesis procedure are discussed. Mossbauer spectroscopy and x-ray diffraction were used to identify the structural phases and the former was used also to study the magnetism of the nanoparticles. All the nanoparticles were observed to be ferromagnetic in this size range. If excess C2H4 appears in the reactant gas mixture, several monolayers of pyrolytic carbon were observed to form on the particle surface, as deduced from transmission electron microscopy and Raman scattering studies. Results of thermo-gravimetric analysis/mass spectroscopy studies of this carbon coating indicate it is gasified in hydrogen at temperatures T ∼ 250 °C.

scholarly journals Photocatalytic Degradation of Organic Contaminants by BiVO4/Graphene Oxide Nanocomposite

2018 ◽  
Vol 15 (11) ◽  
pp. 787-792 ◽  
Author(s):  
Dang Trung Tri TRINH ◽  
Duangdao CHANNEI ◽  
Willawan KHANITCHAIDECHA ◽  
Auppatham NAKARUK
Keyword(s):  
Photocatalytic Activity ◽  
Graphene Oxide ◽  
Organic Contaminants ◽  
Hydrothermal Process ◽  
Monoclinic Structure ◽  
X Ray Diffraction ◽  
Electron Hole ◽  
X Ray ◽  
Transmission Electron ◽  
Adsorbent Capacity

In the present work, a nanocomposite of bismuth vanadate (BiVO4) and Graphene oxide (GO) was synthesized successfully by using hydrothermal process. The properties of BiVO4/GO nanocomposite were examined by various techniques including X-ray diffraction (XRD) and transmission electron microscopy (TEM). The XRD data indicated that pure BiVO4 nanoparticles had a monoclinic structure. Similarly, BiVO4/GO nanocomposite had the same structure without the peak of GO due to the transmission from GO to reduced GO during hydrothermal process. TEM images revealed that BiVO4 particles were integrated effectively with the GO sheets. The photocatalysis performance was evaluated by the degradation of methylene blue (MB) in an aqueous under the irradiation of visible light. The result showed that BiVO4/GO nanocomposites had higher photocatalytic activity than pure BiVO4 nanoparticles. The explanation was that GO sheets enhanced the separation of electron–hole pairs and the adsorbent capacity leading to improved photocatalytic activity.

Precursor to High Purity Carbon Nanotubes: A Step by Step Evaluation of Carbon Yield

2009 ◽  
Vol 6 ◽  
pp. 75-87 ◽  
Author(s):  
K.N. Patil ◽  
Chetan S. Solanki
Keyword(s):  
Electron Microscopy ◽  
Carbon Nanotubes ◽  
Thermo Gravimetric Analysis ◽  
Gravimetric Analysis ◽  
X Ray Diffraction ◽  
Thermo Gravimetric ◽  
Carrier Gas ◽  
Transmission Electron ◽  
Annealing Step ◽  
Catalyst Type

Yield of carbon nanotubes (CNTs) depends on numerous process parameters such as temperature of synthesis, type of catalyst, type of precursor, time of precursor flow and partial pressure of precursor gas as well as carrier gas, etc. Experiments were performed in order to find the optimum temperature of synthesis for varying time of precursor flow. The yield was evaluated in terms of mass of crystalline CNTs per gram of substrate and/or catalyst. The CNTs were grown on a calcium carbonate (CaCO3) substrate, with iron-cobalt (Fe-Co) as a catalyst, using acetylene (C2H2) as a precursor gas and argon (Ar) as a carrier gas. A three-stage purification process, incorporating two acid treatment steps and one annealing step, was used for purification which ensures high grade purity of CNTs. The highest yield of 21.4 g of CNTs per g of catalyst was achieved at 700oC for 60 min of synthesis. The CNTs were characterized by Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), X-ray Diffraction (XRD), Raman, Thermo-gravimetric analysis (TGA), and Gas chromatography (GC).

scholarly journals Structural and Magnetic Properties of La0.9Sr0.1MnO3 Nanoparticles Prepared via Sol-gel Process

2019 ◽  
Vol 70 (6) ◽  
pp. 2044-2047
Author(s):  
Alexandru-Horatiu Marincas ◽  
Firuta Goga ◽  
Roxana Dudric ◽  
Crina Suciu ◽  
Alexandra Avram ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Magnetic Measurements ◽  
Sol Gel ◽  
Thermo Gravimetric Analysis ◽  
Gravimetric Analysis ◽  
X Ray Diffraction ◽  
Thermo Gravimetric ◽  
X Ray ◽  
Transmission Electron ◽  
Sol Gel Process

In the present paper, nanosized La0.9Sr0.1MnO3 particles were synthesized via a facile modified sol-gel route using two cheap and environmentally friendly organic chemicals, namely sucrose and pectin. The obtained powders were characterized by thermo gravimetric analysis (TGA), X-ray diffraction (XRD), transmission electron microscopy (TEM), and magnetic measurements. The optimal temperature for obtaining nanosized particles was determined as 1000�C and 1h dwell time was enough to obtain crystalline nanoparticles. Magnetic properties of samples calcined with different calcination period were analyzed and both samples shown a transition temperature around 274 K.

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