Filling of Carbon Nanotubes with Selenium by Vapor Phase Process

2006 ◽  
Vol 6 (1) ◽  
pp. 82-86 ◽  
Author(s):  
Jérôme Chancolon ◽  
Françoise Archaimbault ◽  
Alain Pineau ◽  
Sylvie Bonnamy
Keyword(s):  
Carbon Nanotubes ◽  
Vapor Phase ◽  
Capillary Condensation ◽  
Phase Method ◽  
X Ray Diffraction ◽  
Filling Rate ◽  
X Ray ◽  
Full Control ◽  
Trigonal Structure ◽  
Phase Process

A vapor phase method was developed to fill different kinds of nanotubes (including multiwall and singlewall nanotubes), which inner diameters range from 200 down to 1.5 nm. Experiments were performed with selenium in a sealed reactor in order to control the selenium partial pressure. This process allows a full control of the nanotube filling (partial or complete), i.e., either a selective diameter filling or a full filling rate. The weight gain of all the samples was plotted for different reaction temperature as a function of selenium pressure. Experimental isotherms are characteristic of capillary condensation of selenium, which occurs at first in the smallest nanotube inner diameters. X-ray diffraction data show that selenium confined in nanotubes with diameters larger than 3 nm keeps its trigonal structure.

AIN/GaN and AIGaN/GaN Heterostructures Grown by HVPE on SiC Substrates

1997 ◽  
Vol 482 ◽  
Author(s):  
Yu. V. Melnik ◽  
A. E. Nikolaev ◽  
S. I. Stepanov ◽  
A. S. Zubrilov ◽  
I. P. Nikitina ◽  
...  
Keyword(s):  
Growth Rate ◽  
Electron Beam ◽  
Vapor Phase ◽  
Electron Spectroscopy ◽  
Auger Electron ◽  
Hydride Vapor Phase Epitaxy ◽  
X Ray Diffraction ◽  
Electrical Measurements ◽  
X Ray ◽  
Micro Analysis

AbstractGaN, AIN and AIGaN layers were grown by hydride vapor phase epitaxy. 6H-SiC wafers were used as substrates. Properties of AIN/GaN and AIGaN/GaN structures were investigated. AIGaN growth rate was about 1 μm/min. The thickness of the AIGaN layers ranged from 0.5 to 5 μm. The AIN concentration in AIGaN layers was varied from 9 to 67 mol. %. Samples were characterised by electron beam micro analysis, Auger electron spectroscopy, X-ray diffraction and cathodoluminescence.Electrical measurements performed on AIGaN/GaN/SiC samples indicated that undoped AIGaN layers are conducting at least up to 50 mol. % of AIN.

Synthesis of Nanocomposites of V2OO5©Selenium Nanoparticles and Multiwalled Carbon Nanotubes for Antimicrobial Activity

2021 ◽  
Vol 21 (11) ◽  
pp. 5673-5680
Author(s):  
Muthukrishnan Francklin Philips ◽  
Jothirathinam Thangarathinam ◽  
Jayakumar Princy ◽  
Cyril Arockiaraj Crispin Tina ◽  
Cyril Arockiaraj Crispin Tina ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Antimicrobial Activity ◽  
Multiwalled Carbon Nanotubes ◽  
Xrd Analysis ◽  
X Ray Diffraction ◽  
Multiwalled Carbon ◽  
X Ray ◽  
Functionalized Multiwalled Carbon Nanotubes ◽  
Uv Visible ◽  
Micro Organisms

The authors report the preparation of the nanocomposite comprising of vanadium pentoxide (V2O5) and selenium (Se) nanoparticles and functionalized multiwalled carbon nanotubes (MWCNTs) (V2O5@Se NPs/MWCNTs). Since Se NPs possesses extraordinary physicochemical properties including larger surface area with higher adsorption capacity, V2O5 NPs were adsorbed onto Se NPs surface through physisorption process (designated as V2O5@Se NPs). The nanocomposite synthesized hydrothermally was evaluated for its antimicrobial activity. The morphology and microstructure of the nanocomposite were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis, respectively. Fourier transform infrared spectroscopy (FTIR) and UV-Visible spectroscopy (UV-Vis) were employed to analyze the spectral properties of nanocomposite. The microbicidal efficacy of nanocomposite was tested against Gram-negative (G-)ZGram-positive (G+) bacteria and fungus. This is the first report on the synthesis of V2O5@Se NPs/MWCNTs nanocomposites by chemical method that showed microbicidal effect on micro-organisms. The thiol (-SH) units facilitates the enrichment of V2O5@Se NPs onto MWCNTs surface. Ultimately, it reflects on the significant antimicrobial activity of V2O5@Se NPs/MWCNTs.

Crystal structure of microwave dielectric ceramics Ba[(Mg1−xCdx)0.33Nb0.67]O3

2007 ◽  
Vol 22 (4) ◽  
pp. 295-299
Author(s):  
J. X. Deng ◽  
X. R. Xing ◽  
J. Chen ◽  
R. B. Yu ◽  
G. R. Liu ◽  
...  
Keyword(s):  
Synthesis Temperature ◽  
Partial Substitution ◽  
Quantitative Phase Analysis ◽  
X Ray Diffraction ◽  
Low Frequencies ◽  
X Ray ◽  
Microwave Dielectric ◽  
Trigonal Structure ◽  
Ordering Degree ◽  
Dielectric Ceramics

A series of complex perovskite solid solutions of Ba[(Mg1−xCdx)0.33Nb0.67]O3 have been synthesized by the columbite method. Detailed Rietveld refinement of their X-ray diffraction data show that Ba[(Mg1−xCdx)0.33Nb0.67]O3 has an order trigonal structure. The ordering degree as determined by the B-site occupancies increases with the partial substitution of Cd for Mg. However, a decrease in the ordering degree in the Ba(Cd0.33Nb0.67)O3 sample is observed, which can be attributed to a relatively lower synthesis temperature. All the impurity phases are successfully identified by X-ray quantitative phase analysis. Dielectrics properties at low frequencies for all the Ba[(Mg1−xCdx)0.33Nb0.67]O3 compounds have been measured successfully.

scholarly journals Observation and Characterization of Fragile Organometallic Molecules Encapsulated in Single-Wall Carbon Nanotubes

2014 ◽  
Vol 2014 ◽  
pp. 1-5
Author(s):  
Daisuke Ogawa ◽  
Ryo Kitaura ◽  
Takeshi Saito ◽  
Shinobu Aoyagi ◽  
Eiji Nishibori ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
High Yield ◽  
Single Wall Carbon Nanotubes ◽  
X Ray Diffraction ◽  
Single Wall Carbon ◽  
X Ray ◽  
Transmission Electron ◽  
Organometallic Molecules ◽  
X Ray Absorption

Thermally fragile tris(η5-cyclopentadienyl)erbium (ErCp3) molecules are encapsulated in single-wall carbon nanotubes (SWCNTs) with high yield. We realized the encapsulation of ErCp3with high filling ratio by using high quality SWCNTs at an optimized temperature under higher vacuum. Structure determination based on high-resolution transmission electron microscope observations together with the image simulations reveals the presence of almost free rotation of each ErCp3molecule in SWCNTs. The encapsulation is also confirmed by X-ray diffraction. Trivalent character of Er ions (i.e., Er3+) is confirmed by X-ray absorption spectrum.

Synthesis and properties of double gadolinium tellurites

2021 ◽  
Vol 103 (3) ◽  
pp. 67-73
Author(s):  
A.A. Toibek ◽  
◽  
K.T. Rustembekov ◽  
D.A. Kaikenov ◽  
M. Stoev ◽  
...  
Keyword(s):  
Phase Analysis ◽  
Solid Phase ◽  
Heat Capacities ◽  
Ceramic Technology ◽  
Phase Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cell Parameters ◽  
Temperature Range ◽  
Diffraction Patterns

For the first time, double gadolinium tellurites of the composition GdMIITeO4.5 (MII — Sr, Ba) were synthesized by the solid-phase method. The solid-phase synthesis of samples was carried out from decrepitated gadolinium (III) and tellurium (IV) oxides, strontium, and barium carbonates according to the standard ceramic technology. The synthesis was carried out in the temperature range of 800-1100 °C. The samples obtained were confirmed by X-ray phase analysis. X-ray phase analysis was carried out on an Empyrean instrument in the XRDML Pananalitical format. The intensity of the diffraction maxima was estimated on a 100-point scale. X-ray diffraction patterns indexing of the powder of gadolinium tellurites — alkaline earth metals studied were carried out by the homology method. The reliability and correctness of the results of indexing the X-ray diffraction patterns are confirmed by the good agreement between the experimental and calculated values of the interplanar distances (d) and the agreement between the values of the X-ray and pycnometric densities. It was found that compounds GdSrTeO4.5 and GdBaTeO4.5 crystallize in the monoclinic system and have the unit cell parameters, namely GdSrTeO4.5 — a = 12.7610, b = 10.4289, c = 8.6235 Å, V° = 1141.83 Å3, β = 95.77°, Z = 5, ρrent. = 3.22, ρpikn. = (3.10±0.09) g/cm3; GdBaTeO4.5 — a = 15.7272, b = 15.8351, c = 7.1393 Å, V° = 1769.72 Å3, β = 95.53°, Z = 8, ρrent = 3.71, ρpick = (3.61±0.10) g/cm3. Using the Landiya method, the standard heat capacities of the compounds were estimated from the calculated values of the standard entropies, and the temperature dependences of the heat capacities of the gadolinium tellurites synthesized were determined in the temperature range of 298–850 K.

scholarly journals Effect of Zirconia Polymorph on Vapor-Phase Ketonization of Propionic Acid

Catalysts ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 768 ◽  
Author(s):  
Shuang Ding ◽  
Jiankang Zhao ◽  
Qiang Yu
Keyword(s):  
Propionic Acid ◽  
Vapor Phase ◽  
Surface Concentration ◽  
X Ray Diffraction ◽  
In Situ Drifts ◽  
X Ray ◽  
Surface Intermediates ◽  
Temperature Programmed ◽  
Diffuse Reflectance Infrared

Vapor-phase ketonization of propionic acid derived from biomass was studied at 300–375 °C over ZrO2 with different zirconia polymorph. The tetragonal ZrO2 (t-ZrO2) are more active than monoclinic ZrO2 (m-ZrO2). The results of characterizations from X-ray diffraction (XRD) and Raman suggest m-ZrO2 and t-ZrO2 are synthesized by the solvothermal method. NH3 and CO2 temperature-programmed desorption (NH3-TPD and CO2-TPD) measurements show that there were more medium-strength Lewis acid base sites with lower coordination exposed on m-ZrO2 relative to t-ZrO2, increasing the adsorption strength of propionic acid. The in situ DRIFTS (Diffuse reflectance infrared Fourier transform spectroscopy) of adsorbed propionic acid under ketonization reaction reveal that as the most abundant surface intermediates, the monodentate propionates are more active than bidentate propionates. In comparison with m-ZrO2, the t-ZrO2 surface favors monodentate adsorption over bidentate adsorption. Additionally, the adsorption strength of monodentate propionate is weaker on t-ZrO2. These differences in adsorption configuration and adsorption strength of propionic acid are affected by the zirconia structure. The higher surface concentration and weaker adsorption strength of monodentate propionates contribute to the higher ketonization rate in the steady state.

scholarly journals Fabrication of MoS2 Nanoflakes Supported on Carbon Nanotubes for High Performance Anode in Lithium-Ion Batteries (LIBs)

2019 ◽  
Vol 2019 ◽  
pp. 1-7
Author(s):  
T. Minh Nguyet Nguyen ◽  
Vinh-Dat Vuong ◽  
Mai Thanh Phong ◽  
Thang Van Le
Keyword(s):  
Carbon Nanotubes ◽  
Lithium Ion Batteries ◽  
High Performance ◽  
Lithium Ion ◽  
Interlayer Spacing ◽  
X Ray Diffraction ◽  
Multiwalled Carbon ◽  
X Ray ◽  
Functionalized Multiwalled Carbon Nanotubes ◽  
20 Nm

Molybdenum disulfide (MoS2), an inorganic-layered material similar to structure of graphite, was randomly dispersed onto the surface of functionalized multiwalled carbon nanotubes to synthesized nanocomposite MoS2/CNT. The as-obtained product was characterized via SEM, TEM, TGA, X-ray diffraction, and Raman spectroscopies. It was confirmed from XRD that MoS2 layers with interlayer spacing of 0.614 nm were successfully produced. TEM images and Raman spectra indicated a random distribution of 20 nm sized nanoflake MoS2 on the surface of MWNTs. The electrochemical performance of materials are expected to pave the way for the utilized anode material for lithium-ion batteries.

Electrochemical Properties of Multi-Wall Carbon Nanotubes as a Novel Negative Electrode for Calcium Secondary Batteries

2016 ◽  
Vol 859 ◽  
pp. 75-78
Author(s):  
Chang Hee Lee ◽  
Chang Su Kim ◽  
Yun Taek Jeong ◽  
Jun Hwan Kim ◽  
Soon Ki Jeong ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Electrochemical Performance ◽  
Calcium Ions ◽  
Calcium Ion ◽  
Ethylene Carbonate ◽  
Negative Electrode ◽  
X Ray Diffraction ◽  
X Ray ◽  
Multi Wall Carbon Nanotubes ◽  
Discharge Capacities

We investigated the electrochemical behavior and properties of multi-wall carbon nanotubes (MWCNTs) as a novel negative electrode for calcium ion batteries during charging and discharging. The second charge and discharge capacities were ~63 and ~43 mAh g–1 in propylene carbonate-based electrolyte and ~86 and ~60 mAh g–1 in ethylene carbonate-based electrolyte, respectively. X-ray diffraction analysis results showed that the inter-layer distance of the MWCNTs was increased after charging, indicating that calcium ions were intercalated into the MWCNT graphitic sheets during the charging. The electrochemical performance of the MWCNT electrode was improved by using ball milling to introduce defects.

Various Types of Pt-Ni Binary Catalysts Supported on the Carbon Nanotubes as Cathode Catalysts for DMFC

2007 ◽  
Vol 119 ◽  
pp. 247-250 ◽  
Author(s):  
Yon Ki Seo ◽  
Yong Hwan Kim ◽  
Uoo Chang Chung ◽  
Won Sub Chung
Keyword(s):  
Carbon Nanotubes ◽  
Diffraction Pattern ◽  
Xrd Analysis ◽  
Metal Catalysts ◽  
X Ray Diffraction ◽  
X Ray ◽  
Electrochemical Tests ◽  
Cathode Catalysts ◽  
Ni Alloy ◽  
Binary Catalysts

Several methods for loading of Pt-Ni binary catalysts on the CNTs were tested. Using the CNTs treated HNO3, the catalysts supported Pt, Ni separately(Pt&Ni/CNT) and Pt-Ni alloy(Pt- Ni/CNTs) were made respectively. The results of supporting were confirmed by TEM and XRD analysis. TEM images show that metal catalysts were loaded uniformly and finely on the CNTs. By XRD analysis, the peaks of Pt&Ni/CNTs displayed Pt and Ni peaks respectively. Also it was found that the peaks of Pt were shifted to the higher 2theta angle in X-ray diffraction pattern which indicated that Pt-Ni alloy was formed successfully(Pt-Ni/CNTs). In addition, electrochemical tests for cathode catalysts of DMFC were performed. As the results, Pt-Ni/CNTs was most suitable for cathode catalysts of DMFC.

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