scholarly journals Room temperature Suzuki coupling of aryl iodides, bromides, and chlorides using a heterogeneous carbon nanotube-palladium nanohybrid catalyst

2015 ◽  
Vol 5 (4) ◽  
pp. 2388-2392 ◽  
Author(s):  
Dhanaji V. Jawale ◽  
Edmond Gravel ◽  
Caroline Boudet ◽  
Nimesh Shah ◽  
Valérie Geertsen ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Carbon Nanotube ◽  
Palladium Nanoparticles ◽  
Room Temperature ◽  
Suzuki Coupling ◽  
Layer By Layer ◽  
Aryl Iodides ◽  
Multi Walled Carbon Nanotubes ◽  
Heterogenous Catalyst ◽  
Walled Carbon Nanotubes

Palladium nanoparticles were immobilized on multi-walled carbon nanotubes by a layer-by-layer approach, resulting in a well-defined assembly that was used as a heterogenous catalyst in Suzuki couplings.

scholarly journals Carbon nanotubes functionalized by salts containing stereogenic heteroatoms as electrodes in their battery cells

2016 ◽  
Vol 18 (4) ◽  
pp. 22-26 ◽  
Author(s):  
Sandra Zdanowska ◽  
Magdalena Pyzalska ◽  
Józef Drabowicz ◽  
Damian Kulawik ◽  
Volodymyr Pavlyuk ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Cyclic Voltammetry ◽  
Carbon Nanotube ◽  
Electrochemical Properties ◽  
Electrolyte Solution ◽  
Room Temperature ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes ◽  
Standard Techniques ◽  
Charge Discharge

Abstract This paper concentrates on electrochemical properties of groups of multi-walled carbon nanotubes (MWCNT) functionalized with substituents containing a stereogenic heteroatom bonded covalently to the surface of the carbon nanotube. This system was tested in Swagelok-type cells. The cells comprised a system (functionalized CNT with salts containing S and P atoms) with a working electrode, microfiber separators soaked with electrolyte solution, and a lithium foil counter/reference (commercial LiCoO2) electrode. The electrolyte solution was 1 M LiPF6 in propylene carbonate. Using standard techniques (cyclic voltammetry/chronopotentiometry), galvanostatic cycling was performed on the cells at room temperature with a CH Instruments Model 600E potentiostat/galvanostat electrochemical measurements. Methods of functionalization CNT were compared in terms of the electrochemical properties of the studied systems. In all systems, the process of charge/discharge was observed.

scholarly journals A Room Temperature VOCs Gas Sensor Based on a Layer by Layer Multi-Walled Carbon Nanotubes/Poly-ethylene Glycol Composite

Sensors ◽  
2018 ◽  
Vol 18 (9) ◽  
pp. 3113 ◽  
Author(s):  
Zitao Liu ◽  
Tuoyu Yang ◽  
Ying Dong ◽  
Xiaohao Wang
Keyword(s):  
Carbon Nanotubes ◽  
Gas Sensor ◽  
Room Temperature ◽  
High Sensitivity ◽  
Fast Response ◽  
Layer By Layer ◽  
Resistance Change ◽  
Multi Walled Carbon Nanotubes ◽  
Electric Nose ◽  
Walled Carbon Nanotubes

Sensitive detection of volatile organic compounds (VOCs) is significant for environmental monitoring and medical applications. In this work, multi-walled carbon nanotubes (MWCNTs) and polyethylene glycol (PEG) that have good adsorption for VOCs, were sprayed layer by layer on an interdigitated electrode (IDE) to build a sensitive VOCs gas sensor. The relative resistance change (△R/R) when the sensor was exposed to VOCs was measured. The sensor showed high sensitivity to acetone, ethanol, isopropanol and isoprene with fast response (110 ± 5 s) and recovery (152 ± 5 s) at room temperature, and the lower detection limit (LDL) of the sensor reached 9 ppm. With the micro-fabricated IDE structure, the sensor can be easily built into an electric nose for VOC recognition and measurement.

scholarly journals A Facile and Efficient Bromination of Multi-Walled Carbon Nanotubes

Materials ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3161
Author(s):  
Sandra Zarska ◽  
Damian Kulawik ◽  
Volodymyr Pavlyuk ◽  
Piotr Tomasik ◽  
Alicja Bachmatiuk ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Room Temperature ◽  
Covalent Attachment ◽  
Closed Vessel ◽  
Dangling Bonds ◽  
Magnetic Stirrer ◽  
Defect Sites ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes ◽  
Covalently Bound

The bromination of multi-walled carbon nanotubes (MWCNT) was performed with vapor bromine in a closed vessel, and they were subjected to intensive stirring with a magnetic stirrer for up to 14 days. The efficiency of bromination was compared depending upon duration. The structure and surface of the crude and purified products were characterized by detailed physicochemical analyses, such as SEM/EDS, TEM, XRD, TGA, Raman, and XPS spectroscopies. The studies confirmed the presence of bromine covalently bound with nanotubes as well as the formation of inclusion MWCNT–Br2 complexes. It was confirmed that Br2 molecules are absorbed on the surface of nanotubes (forming the CNT-Br2 complex), while they can dissociate close to dangling bonds at CNT defect sites with the formation of covalent C−Br bonds. Thus, any covalent attachment of bromine to the graphitic surface achieved around room temperature is likely related to the defects in the MWCNTs. The best results, i.e., the highest amount of attached Br2, were obtained for brominated nanotubes brominated for 10 days, with the content of covalently bound bromine being 0.68 at% (by XPS).

Effect of Expanded Temperature on Microstructure of Carbon Nanotubes/Expanded Graphite Composites

2013 ◽  
Vol 716 ◽  
pp. 373-378
Author(s):  
Qian Zhang ◽  
Xin Bao Gao ◽  
Tian Peng Li
Keyword(s):  
Carbon Nanotubes ◽  
Composite Material ◽  
High Temperature ◽  
Carbon Nanotube ◽  
Physical Adsorption ◽  
Expanded Graphite ◽  
Graphite Flake ◽  
Graphite Composite ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

Carbon nanotube/expanded graphite composite material was prepared by expanding the mixture of multi-walled carbon nanotubes and expansible graphite under the condition of high temperature. The microstructure and composition was studied by using SEM and XRD. The study shows that the tubular structure of carbon nanotubes in the composite material is changed by high temperature expanding process, and the microstructure is different with different expanding temperature. When the expanding temperature was 900°C, carbon nanotubes transformed, then attached to the surface of expanded graphite flake, so carbon nanotubes and expanding graphite combined strongly; globular carbon nanotubes attached to the surface of expanded graphite flake at the temperature of 700°C, both were combined much more strongly; carbon nanotubes retained the tube structure at the temperature of 500°C, combination was looser due to the simple physical adsorption. The result shows that the choice of expanding temperature has an important effect on microstructure of carbon nanotube/expanded graphite composite material.

Room-temperature hydrogen sensing properties of SnO2-coated multi-walled carbon nanotubes

Carbon ◽  
2010 ◽  
Vol 48 (13) ◽  
pp. 3976
Author(s):  
Xue Sun ◽  
Hai-Tao Fang ◽  
Hui-Long Yu ◽  
Yi Chu ◽  
Bao-You Zhang ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Room Temperature ◽  
Sensing Properties ◽  
Hydrogen Sensing ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

scholarly journals Carbon Nanofibers from Carbon Nanotubes by 1.2 keVAr+Sputtering at Room Temperature

2014 ◽  
Vol 2014 ◽  
pp. 1-5 ◽  
Author(s):  
Shuang-Xi Xue ◽  
Qin-Tao Li ◽  
Xian-Rui Zhao ◽  
Qin-Yi Shi ◽  
Zhi-Gang Li ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Carbon Nanotubes ◽  
Carbon Nanofibers ◽  
Carbon Nanoparticles ◽  
Room Temperature ◽  
Ion Irradiation ◽  
Transmission Electron ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes ◽  
Carbon Nanowires

Multi-walled carbon nanotubes (MWCNTs) were irradiated by 1.2 keV Ar ion beams for 15–60 min at room temperature with current density of 60 µA/cm2. The morphology and microstructure are investigated by scanning electron microscopy, transmission electron microscopy and Raman spectroscopy. The results show that carbon nanofibers are achieved after 60 min ion irradiation and the formation of carbon nanofibers proceeds through four periods, carbon nanotubes—amorphous carbon nanowires—carbon nanoparticles along the tube axis—conical protrusions on the nanoparticles surface—carbon nanofibers from the conical protrusions.

The Effect of Nanotube Loading and Dispersion on the Three-Dimensional Nanostructure of Carbon Nanotube-Conducting Polymer Composite Films

2002 ◽  
Vol 739 ◽  
Author(s):  
Mark Hughes ◽  
George Z. Chen ◽  
Milo S. P. Shaffer ◽  
Derek J. Fray ◽  
Alan H. Windle
Keyword(s):  
Carbon Nanotubes ◽  
Carbon Nanotube ◽  
Conducting Polymer ◽  
Polymer Composite ◽  
Electrochemical Polymerization ◽  
Composite Films ◽  
Three Dimensional ◽  
Ionic Diffusion ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

ABSTRACTNanoporous composite films of multi-walled carbon nanotubes (MWNTs) and either polypyrrole (PPy) or poly(3-methylthiophene) (P3MeT) were grown using an electrochemical polymerization technique in which the nanotubes and conducting polymer were deposited simultaneously. The concentration and dispersion of MWNTs in the polymerization electrolyte was found to have a significant effect on the thickness of polymer coated on each MWNT and hence the loading of MWNTs in the films produced. It has been shown that for an increasing concentration of MWNTs in the polymerization electrolyte, the thickness of polymer coated on each MWNT decreases. This relationship made it possible to minimize ionic diffusion distances within the nanoporous MWNT-PPy films produced, reducing their electrical and ionic resistance and increasing their capacitance relative to similarly prepared pure PPy films.

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