scholarly journals Characterization and Hydrogen Storage of Surface-Modified Multiwalled Carbon Nanotubes for Fuel Cell Application

2012 ◽  
Vol 2012 ◽  
pp. 1-12 ◽  
Author(s):  
Kuen-Song Lin ◽  
Yao-Jen Mai ◽  
Shin-Rung Li ◽  
Chia-Wei Shu ◽  
Chieh-Hung Wang
Keyword(s):  
Carbon Nanotubes ◽  
Multiwalled Carbon Nanotubes ◽  
Storage Capacity ◽  
Early Stage ◽  
Bond Distance ◽  
Pd Nanoparticles ◽  
Synthesis Process ◽  
Ni Catalyst ◽  
Multiwalled Carbon ◽  
Solvothermal Route

The synthesis, identification, and H2storage of multiwalled carbon nanotubes (MWCNTs) have been investigated in the present work. MWCNTs were produced from the catalytic-assembly solvent (benzene)-thermal (solvothermal) route. Reduction of C6Cl6with metallic potassium was carried out in the presence of Co/Ni catalyst precursors at 503–623 K for 12 h. XRD patterns indicated that the abstraction of Cl from hexachlorobenzene and the formation of KCl precipitates were involved in the early stage of the synthesis process of MWCNTs. This result offers further explanation for the formation of MWCNT structure and yield using the solvothermal route depending on the Co/Ni catalyst precursors. The diameter of MWCNTs ranged between 30 and 100 nm and the H2storage capacity of MWCNTs improved when 2.7–3.8 wt% Pd or NaAlH4were doped. The XANES/EXAFS spectra revealed that the Co/Ni catalyst precursors of the MWCNT synthesis were in metallic form and Pd atoms possessed a Pd–Pd bond distance of 2.78 Å with a coordination number of 9.08. Ti-NaAlH4or Pd nanoparticles were dispersed on MWCNTs and facilitated to improve the H2storage capacity significantly with the surface modification process.

Synthesis, Characterization, and Hydrogen-Storage Ability of Surface-Modified Multi-Wall Carbon Nanotubes

2006 ◽  
Author(s):  
Kuen-Song Lin ◽  
Chi-Nan Ku ◽  
Chien-Te Hsieh ◽  
Shih-Hung Chan ◽  
Ay Su
Keyword(s):  
Carbon Nanotubes ◽  
Hydrogen Storage ◽  
Storage Capacity ◽  
Bond Distance ◽  
Pd Nanoparticles ◽  
Ni Catalyst ◽  
Multi Wall Carbon Nanotubes ◽  
Surface Modified ◽  
X Ray Absorption ◽  
Adsorptive Properties

Carbon nanotubes (CNTs) have attracted increasing attention because of their unique structural, mechanical, and electronic properties. Surface chemistry modifications are also useful and critical to manipulate the adsorptive properties of CNTs and develop their hydrogen storage potential. Therefore, the synthesis or identification of multi-wall carbon nanotubes (MWCNTs) and H2 storage capacity in MWCNTs were investigated. Experimentally, the MWCNTs were produced from the catalytic-assembly benzene-thermal routes by reduction of C6Cl6 with metallic K or Na in the presence of Co/Ni catalyst precursors at 503–623 K. The diameters of K-MWCNTs and Na-MWCNTs ranged from 30–100 and 20–60 nm, respectively. The H2 storage capacity of MWCNTs improved by Pd or NaAlH4 ranged from 2.5–3.5 wt%. Extended X-ray absorption fine structural (EXAFS) spectra showed that the Pd or PdCl2 possess a Pd-Pd or Pd-Cl bond distance of 2.76 or 2.25 Å with a coordination number of 6 or 2, respectively. Therefore, Pd nanoparticles are well dispersed on MWCNTs, which may improve the H2 storage capacity significantly.

Enhanced Li Storage Capacity in 3 nm Diameter SnO2 Nanocrystals Firmly Anchored on Multiwalled Carbon Nanotubes

2011 ◽  
Vol 115 (44) ◽  
pp. 22062-22067 ◽  
Author(s):  
Yun-Ho Jin ◽  
Kyung-Mi Min ◽  
Seung-Deok Seo ◽  
Hyun-Woo Shim ◽  
Dong-Wan Kim
Keyword(s):  
Carbon Nanotubes ◽  
Multiwalled Carbon Nanotubes ◽  
Storage Capacity ◽  
Multiwalled Carbon ◽  
Sno2 Nanocrystals ◽  
Li Storage

scholarly journals Heterogeneous Organo- and Metal Catalysis Using Phosphine Oxide Derivatives Anchored on Multiwalled Carbon Nanotubes

2020 ◽  
Vol 6 (3) ◽  
pp. 57
Author(s):  
Maria Cristina Ligi ◽  
Anna Flis ◽  
Giacomo Biagiotti ◽  
Giulia Serrano ◽  
K. Michał Pietrusiewicz ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Multiwalled Carbon Nanotubes ◽  
Heterogeneous Catalysts ◽  
Pd Nanoparticles ◽  
Phosphine Oxides ◽  
Heck Reactions ◽  
Multiwalled Carbon ◽  
Metal Catalysis ◽  
Mitsunobu Reactions ◽  
Oxidized Multiwalled Carbon Nanotubes

Oxidized multiwalled carbon nanotubes were modified anchoring phosphine oxides and used as heterogeneous catalysts. A proper substitution of the phosphine oxides allowed the use of the Tour reaction and the nitrene cycloaddition to obtain functionalized carbon nanotubes (CNT) with a loading up to 0.73 mmol/g of material. The catalysts proved efficient in Wittig reactions, Mitsunobu reactions, and Staudinger ligations. Furthermore, the phosphorus decorated CNT were used to produce nanocomposite with Pd nanoparticles able to catalyze Heck reactions.

scholarly journals Uniform Dispersion of Multiwalled Carbon Nanotubes in Copper Matrix Nanocomposites Using Metal Injection Molding Technique

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Ali Samer Muhsan ◽  
Faiz Ahmad ◽  
Norani M. Mohamed ◽  
Puteri Sri Melor Megat Yusoff ◽  
Muhammad Rafi Raza
Keyword(s):  
Carbon Nanotubes ◽  
Injection Molding ◽  
Multiwalled Carbon Nanotubes ◽  
Elevated Temperatures ◽  
Metal Injection Molding ◽  
Ni Catalyst ◽  
Multiwalled Carbon ◽  
Uniform Dispersion ◽  
Pure Cu ◽  
Matrix Nanocomposites

This work presents a novel fabrication approach of multiwalled carbon nanotubes (MWNTs) reinforced copper (Cu) matrix nanocomposites. A combination of nanoscale dispersion of functionalized MWNTs in low viscose media of dissolved paraffin wax under sonication treatment followed by metal injection molding (MIM) technique was adopted. MWNTs contents were varied from 0 to 10 vol.%. Information about the degree of purification and functionalization processes, evidences on the existence of the functional groups, effect of sonication time on the treated MWNTs, and microstructural analysis of the fabricated Cu/MWNTs nanocomposites were determined using TEM, EDX, FESEM, and Raman spectroscopy analysis. The results showed that the impurities of the pristine MWNTs such as Fe, Ni catalyst, and the amorphous carbon have been significantly removed after purification process. Meanwhile, FESEM and TEM observations showed high stability of MWNTs at elevated temperatures and uniform dispersion of MWNTs in Cu matrix at different volume fractions and sintering temperatures (950, 1000 & 1050°C). The experimentally measured thermal conductivities of Cu/MWNTs nanocomposites showed remarkable increase (11.25% higher than sintered pure Cu) with addition of 1 vol.% MWNTs, and slight decrease below the value of sintered Cu at 5 and 10 vol.% MWNTs.

scholarly journals Pt- and Pd-decorated MWCNTs for vapour and gas detection at room temperature

2015 ◽  
Vol 6 ◽  
pp. 919-927 ◽  
Author(s):  
Hamdi Baccar ◽  
Atef Thamri ◽  
Pierrick Clément ◽  
Eduard Llobet ◽  
Adnane Abdelghani
Keyword(s):  
Carbon Nanotubes ◽  
Volatile Organic Compounds ◽  
Multiwalled Carbon Nanotubes ◽  
Organic Compounds ◽  
Room Temperature ◽  
Surface Defects ◽  
Pd Nanoparticles ◽  
Oxygen Plasma Treatment ◽  
Multiwalled Carbon ◽  
Volatile Organic

Here we report on the gas sensing properties of multiwalled carbon nanotubes decorated with sputtered Pt or Pd nanoparticles. Sputtering allows for an oxygen plasma treatment that removes amorphous carbon from the surface of the carbon nanotubes and creates oxygenated surface defects in which metal nanoparticles nucleate within a few minutes. The decoration with the 2 nm Pt or the 3 nm Pd nanoparticles is very homogeneous. This procedure is performed at the device level (i.e., for carbon nanotubes deposited onto sensor substrates) for many devices in one batch, which illustrates the scalability for the mass production of affordable nanosensors. The response to selected aromatic and non-aromatic volatile organic compounds, as well as pollutant gases has been studied. Pt- and Pd-decorated multiwalled carbon nanotubes show a fully reversible response to the non-aromatic volatile organic compounds tested when operated at room temperature. In contrast, these nanomaterials were not responsive to the aromatic compounds studied (measured at concentrations up to 50 ppm). Therefore, these sensors could be useful in a small, battery-operated alarm detector, for example, which is able to discriminate aromatic from non-aromatic volatile organic compounds in ambient.

Bulk Storage Capacity of Hydrogen in Purified Multiwalled Carbon Nanotubes

2002 ◽  
Vol 106 (5) ◽  
pp. 963-966 ◽  
Author(s):  
Peng-xiang Hou ◽  
Quan-hong Yang ◽  
Shuo Bai ◽  
Shi-tao Xu ◽  
Min Liu ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Multiwalled Carbon Nanotubes ◽  
Storage Capacity ◽  
Bulk Storage ◽  
Multiwalled Carbon
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