Effect of Ultraviolet Irradiation on Photo-Physical and Surface Electronic Properties of MoS2

2020 ◽  
Vol 20 (10) ◽  
pp. 6500-6504
Author(s):  
Vijendra Kumar ◽  
R. K. Shukla ◽  
Jyoti Shakya
Keyword(s):  
Electronic Properties ◽  
Uv Light ◽  
X Ray Diffraction ◽  
Kelvin Probe ◽  
Kelvin Probe Microscopy ◽  
Raman Spectroscopic ◽  
Transmission Electron ◽  
Chemical Exfoliation ◽  
Before And After ◽  
Probe Sonication

In this study, exfoliation of molybdenum disulfide (MoS2) using the chemical exfoliation method was successfully achieved via probe sonication followed by centrifugation. The observed ultravioletvisible (UV-Vis) spectra of the MoS2 dispersions indicated the presence of a few layers of MoS2. The morphological, structural, optical and surface electronic properties before and after UV light irradiation were investigated by the technique of X-ray diffraction, the Raman spectroscopic measurements, transmission electron microscopy (TEM), and the scanning Kelvin probe microscopy (SKPM). It was observed that after UV irradiation, the Fermi level moves towards the valence band.

Preparation and characterization of mesoporous ceria–zirconia–alumina nanocomposite with high hydrothermal stability

2007 ◽  
Vol 22 (11) ◽  
pp. 3201-3209 ◽  
Author(s):  
Md. Hasan Zahir ◽  
Yumi H. Ikuhara ◽  
Shinji Fujisaki ◽  
Koji Sato ◽  
Takayuki Nagano ◽  
...  
Keyword(s):  
Mixed Oxides ◽  
Sol Gel ◽  
Ternary Systems ◽  
Steam Treatment ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
Raman Spectroscopic ◽  
Transmission Electron ◽  
Before And After

CeO2–ZrO2–γ-Al2O3 mixed oxides with different molar compositions have been synthesized by the sol-gel method using nitrate–alkoxide precursors. Some relationships between the molar composition of the ternary systems and their textural and structural properties are presented. CeO2–ZrO2–γ-Al2O3 mixed oxides have been studied and characterized using x-ray diffraction, transmission electron microscopy, and Raman spectroscopic analyses. By complete porosity analyses of all samples before and after hydrothermal (up to 75% steam) treatment at 500 °C, we have been able to optimize a highly hydrothermally stable CeO2–ZrO2–γ-Al2O3 system with a molar ratio of 10:10:80 mol%. γ-Al2O3 alone and CeO2-doped as well as ZrO2-doped γ-Al2O3 were also investigated by the hydrothermal treatment, and their steam-sensitive properties have been compared with those of the ternary CeO2–ZrO2–γ-Al2O3 system.

Effect of MWCNT doping on the structural and optical properties of PVC/PVDF polymer blend

2017 ◽  
Vol 13 (2) ◽  
pp. 4640-4647
Author(s):  
A. M. Abdelghany ◽  
M.S. Meikhail ◽  
S.I. Badr ◽  
A. S. Momen
Keyword(s):  
Surface Damage ◽  
X Ray Diffraction ◽  
Dopant Content ◽  
Casting Technique ◽  
Transmission Electron ◽  
Dopant Level ◽  
Before And After ◽  
Carbon Nano Tubes ◽  
Small Band ◽  
Vibrational Bands

Thin film samples of pristine polyvinyl chloride (PVC), poly vinyldine fluoride (PVDF) in combination with their blend in addition to samples containing factorial mass fraction of multi wall carbon nano-tubes (MWCNTs) in the dopant level were prepared via routine casting technique using tetrahydrofurane (THF) as a common solvent. X-ray diffraction and transmission electron microscopy (TEM) depict the nano-scale (15-25 nm) of functionalized MWCNTs with no surface damage results from functionalization process.X-ray diffraction (XRD) shows a semi-crystalline nature of PVDF with evidence for more than one phase namely a and b phases. The fraction of b phase was calculated and correlated to the dopant content. FTIR optical absorption spectra revels a preservation of the main vibrational bands before and after addition of MWCNTs in the doping level with a presence of new small band 1151 cm-1 assigned for the interaction and complexation between constituents.

scholarly journals Synthesis and Characterization of K-Ta Mixed Oxides for Hydrogen Generation in Photocatalysis

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Beata Zielińska ◽  
Ewa Mijowska ◽  
Ryszard J. Kalenczuk
Keyword(s):  
Diffuse Reflectance ◽  
Hydrogen Generation ◽  
Mixed Oxides ◽  
X Ray Diffraction ◽  
X Ray ◽  
Raman Spectroscopic ◽  
Photocatalytic Hydrogen Generation ◽  
Irregular Structure ◽  
Transmission Electron

K-Ta mixed oxides photocatalysts have been prepared by impregnation followed by calcination. The influence of the reaction temperature (450°C–900°C) on the phase formation, crystal morphology, and photocatalytic activity in hydrogen generation of the produced materials was investigated. The detailed analysis has revealed that all products exhibit high crystallinity and irregular structure. Moreover, two different crystal structures of potassium tantalates such as KTaO3and K2Ta4O11were obtained. It was also found that the sample composed of KTaO3and traces of unreacted Ta2O5(annealed at 600°C) exhibits the highest activity in the reaction of photocatalytic hydrogen generation. The crystallographic phases, optical and vibronic properties were examined by X-ray diffraction (XRD) and diffuse reflectance (DR) UV-vis and resonance Raman spectroscopic methods, respectively. Morphology and chemical composition of the produced samples were studied using a high-resolution transmission electron microscope (HR-TEM) and an energy dispersive X-ray spectrometer (EDX) as its mode.

scholarly journals Polystyrene/Montmorillonite Nanocomposites: Study of the Morphology and Effects of Sonication Time on Thermal Stability

2013 ◽  
Vol 2013 ◽  
pp. 1-12 ◽  
Author(s):  
Mashael Alshabanat ◽  
Amal Al-Arrash ◽  
Waffa Mekhamer
Keyword(s):  
Electron Microscopy ◽  
Thermal Stability ◽  
Solution Method ◽  
Sonication Time ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Polystyrene Matrix ◽  
Before And After ◽  
Silicate Layers ◽  
Thermal Stability Of

Polymer nanocomposites of polystyrene matrix containing 10% wt of organo-montmorillonite (organo-MMT) were prepared using the solution method with sonication times of 0.5, 1, 1.5, and 2 hours. Cetyltrimethylammonium bromide (CTAB) is used to modify the montmorillonite clay after saturating its surface with Na+ions. Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) were used to characterize the montmorillonite before and after modification by CTAB. The prepared nanocomposites were characterized using the same analysis methods. These results confirm the intercalation of PS in the interlamellar spaces of organo-MMT with a very small quantity of exfoliation of the silicate layers within the PS matrix of all samples at all studied times of sonication. The thermal stability of the nanocomposites was measured using thermogravimetric analysis (TGA). The results show clear improvement, and the effects of sonication time are noted.

scholarly journals Oxide-Clay Mineral as Photoactive Material for Dye Discoloration

Minerals ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 132
Author(s):  
Maicon O. Miranda ◽  
Bartolomeu Cruz Viana ◽  
Luzia Maria Honório ◽  
Pollyana Trigueiro ◽  
Maria Gardênnia Fonseca ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Photocatalytic Activity ◽  
Clay Mineral ◽  
Uv Light ◽  
High Photocatalytic Activity ◽  
X Ray Diffraction ◽  
Sem Images ◽  
Zirconium Oxides ◽  
Transmission Electron ◽  
Palygorskite Clay

Titanium and zirconium oxides (TiO2 and ZrO2, respectively) were obtained from alkoxides hydrolyses, and then deposited into palygorskite clay mineral (Pal) to obtain new materials for photocatalytic applications. The obtained materials were characterized by structural, morphological, and textural techniques. X-ray diffraction (XRD) results confirmed the characteristic peaks of oxides and clay transmission electron microscopy (TEM) and scanning electron microscopy (SEM) images of the modified palygorskite with both oxides showed that the clay was successfully modified by the proposed method. The increase in the specific surface area of the clay occurred when TiO2 and ZrO2 were deposited on the surface. The photocatalytic activity of these materials was investigated using the Remazol Blue anion dye under UV light. The evaluated systems presented high photocatalytic activity, reaching approximately 98% of dye discoloration under light. Thus, TiO2–Pal and ZrO2–TiO2–Pal are promising clay mineral-based photocatalysts.

scholarly journals Modification of Titanium Dioxide Nanoparticles with 3-(Trimethoxysilyl)propyl Methacrylate Silane Coupling Agent

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Thuy-Chinh Nguyen ◽  
Tien-Dung Nguyen ◽  
Duc-Toan Vu ◽  
Duc-Phuong Dinh ◽  
Anh-Hiep Nguyen ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Tio2 Nanoparticles ◽  
Coupling Agent ◽  
Titanium Dioxide Nanoparticles ◽  
X Ray Diffraction ◽  
Nano Tio2 ◽  
Propyl Methacrylate ◽  
Transmission Electron ◽  
Before And After ◽  
Modification Of Titanium

This paper presents some characteristics, properties, and morphology of TiO2 nanoparticles (nano-TiO2) modified with various contents of 3-(trimethoxysilyl)propyl methacrylate (TMSPM) coupling agent. The treatment process was carried out in ethanol solvent at 50oC using ammonia as a catalyst for hydrolysis reaction of silane to silanol. Infrared spectroscopy, thermogravimetric analysis, transmission electron microscopy, field emission scanning electron microscopy, dynamic light scattering, ultraviolet-visible spectroscopy, and X-ray diffraction methods were used for determination of the characteristics, properties of nano-TiO2 before and after treatment. In addition, the contact angle and grafting efficiency of TMSPM on the surface of TiO2 nanoparticles was also evaluated. The obtained results confirmed that TMSPM was grafted to the TiO2 nanoparticles, the agglomeration of nano-TiO2 was decreased, and surface of TiO2 nanoparticles became hydrophobic after modification by TMSPM.

Synthesis and characterization of novel poly(HAzPMA-co-SA)/RDX/CdS nanocomposite as a polymer bonded explosive

2020 ◽  
Vol 98 (12) ◽  
pp. 755-763
Author(s):  
Hamid Reza Ghayeni ◽  
Reza Razeghi ◽  
Abolfazl Olyaei
Keyword(s):  
Uv Light ◽  
Light Exposure ◽  
Sodium Acrylate ◽  
Spectroscopic Techniques ◽  
Effective Parameters ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cds Nanorods ◽  
Transmission Electron

Cadmium sulfide nanorods with a length of 69 nm have been prepared by using Cd(OAc)2.2H2O and S8 at 125 °C in the presence of triethylenetetramine as the template agent and coordination agent and characterized by using X-ray diffraction, transmission electron microscopy, FTIR, photoluminescence, and UV–vis absorption spectroscopic techniques. Photocopolymerization of glycidyl methacrylate (GMA) and sodium acrylate (SA) was carried out using CdS nanorods as a photocatalyst under UV light exposure at 400 nm in the presence of β-cyclodextrin (β-CD). To optimization of the effective parameters on the synthesis of copolymer nanocomposite, the amounts of initiator, monomers, and β-CD, duration of pre-deoxygenation, and light wavelength were evaluated. Ring opening of poly(GMA-co-SA)/CdS nanocomposite with NaN3 afforded poly(HAzPMA-co-SA)/CdS nanocomposite and subsequent mixing with RDX in DMF led to the formation of poly(HAzPMA-co-SA)/RDX/CdS nanocomposite as a polymer bonded explosive. All of the copolymer nanocomposites were characterized using various tools of instrumental analysis.

scholarly journals Peroxide Electrochemical Sensor and Biosensor Based on Nanocomposite of TiO2 Nanoparticle/Multi-Walled Carbon Nanotube Modified Glassy Carbon Electrode

Nanomaterials ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 64 ◽  
Author(s):  
L. Andrés Guerrero ◽  
Lenys Fernández ◽  
Gema González ◽  
Marjorie Montero-Jiménez ◽  
Rafael Uribe ◽  
...  
Keyword(s):  
Modified Electrode ◽  
Glassy Carbon ◽  
Sodium Dodecylsulfate ◽  
Modified Electrodes ◽  
Dimethyl Formamide ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Before And After ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

A hydrogen peroxide (H2O2) sensor and biosensor based on modified multi-walled carbon nanotubes (CNTs) with titanium dioxide (TiO2) nanostructures was designed and evaluated. The construction of the sensor was performed using a glassy carbon (GC) modified electrode with a TiO2–CNT film and Prussian blue (PB) as an electrocalatyzer. The same sensor was also employed as the basis for H2O2 biosensor construction through further modification with horseradish peroxidase (HRP) immobilized at the TiO2–fCNT film. Functionalized CNTs (fCNTs) and modified TiO2–fCNTs were characterized by Transmission Electron Microscopy (TEM), Fourier Transform Infrared Spectroscopy (FTIR), and X-Ray DifFraction (XRD), confirming the presence of anatase over the fCNTs. Depending on the surface charge, a solvent which optimizes the CNT dispersion was selected: dimethyl formamide (DMF) for fCNTs and sodium dodecylsulfate (SDS) for TiO2–fCNTs. Calculated values for the electron transfer rate constant (ks) were 0.027 s−1 at the PB–fCNT/GC modified electrode and 4.7 × 10−4 s−1 at the PB–TiO2/fCNT/GC electrode, suggesting that, at the PB–TiO2/fCNT/GC modified electrode, the electronic transfer was improved. According to these results, the PB–fCNT/GC electrode exhibited better Detection Limit (LD) and Quantification Limit (LQ) than the PB–TiO2/fCNT/GC electrode for H2O2. However, the PB film was very unstable at the potentials used. Therefore, the PB–TiO2/fCNT/GC modified electrode was considered the best for H2O2 detection in terms of operability. Cyclic Voltammetry (CV) behaviors of the HRP–TiO2/fCNT/GC modified electrodes before and after the chronoamperometric test for H2O2, suggest the high stability of the enzymatic electrode. In comparison with other HRP/fCNT-based electrochemical biosensors previously described in the literature, the HRP–fCNTs/GC modified electrode did not show an electroanalytical response toward H2O2.

Microwave Sintering of Nanocrystalline TiO2

1990 ◽  
Vol 189 ◽  
Author(s):  
J. A. Eastman ◽  
K. E. Sickafus ◽  
J. D. Katz ◽  
S. G. Boeke ◽  
R. D. Blake ◽  
...  
Keyword(s):  
Microwave Sintering ◽  
Phase Changes ◽  
Microwave Cavity ◽  
Oxygen Stoichiometry ◽  
X Ray Diffraction ◽  
Nanocrystalline Tio2 ◽  
Transmission Electron ◽  
Before And After ◽  
Maximum Temperatures ◽  
Short Time

ABSTRACTNanocrystalline TiO2 compacts having initial approximate mean grain sizes of 14 nm and approximate green densities of 70% of theoretical were sintered by short-time exposure in a 2.45 GHz microwave cavity to maximum temperatures of 800, 1000 or 1200 ºC. Sample densities were measured before and after exposure to microwaves using Archimede's method. Transmission electron microscopy and x-ray diffraction were utilized to monitor grain growth and phase changes. Rutherford backscattering was used to monitor any changes in oxygen stoichiometry. The results of this study indicate that enhanced densification behavior is obtained for microwavesintered samples relative to samples sintered using conventional pressureless-sintering techniques.

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