Hydrogen Spillover from a Metal Oxide Catalyst onto Carbon Nanotubes—Implications for Hydrogen Storage

2002 ◽  
Vol 206 (1) ◽  
pp. 165-168 ◽  
Author(s):  
Angela Lueking ◽  
Ralph T Yang
2014 ◽  
Vol 2 (12) ◽  
pp. 4361-4365 ◽  
Author(s):  
Tengfei Zhang ◽  
Shigehito Isobe ◽  
Yongming Wang ◽  
Hiroshi Oka ◽  
Naoyuki Hashimoto ◽  
...  

It is reported for the first time, that the desorption properties in complex metal hydrides (MgH2, LiAlH4, and LiNH2) are enhanced by a lithium-ion-battery material, LiTi2O4. Three different systems for hydrogen storage are catalysed by one material.


Author(s):  
Alexander V. Shchegolkov ◽  
Elena A. Burakova ◽  
Tatyana P. Dyachkova ◽  
Natalia V. Orlova ◽  
Fadej F. Komarov ◽  
...  

Carbon nanotubes (CNTs) have been synthesized using catalysts of the Ni/Mg, Fe-Co/Al2O and Co-Mo/Al2O3-MgO composition with different component ratios by gas-phase chemical deposition. They differ in geometric parameters, the nature of the inclusion of metal oxide catalyst impurities, and morphological features. To form oxygen-containing functional groups on the surface, CNTS were oxidized with ozone-oxygen mixture (1 vol.% O3) at room temperature for 5 h. Initial and functionalized CNT samples were characterized by scanning and transmission electron microscopy, Raman and IR spectroscopy. It is shown that as a result of oxidation, the amorphous phase is removed from the material, and oxygen-containing groups-OH, >C=O and –O–C–O–are formed on the CNT surface. Also, during functionalization, there is a slight decrease in the specific surface area of the studied nanotube samples. The electrochemical behavior of initial and functionalized carbon nanotubes in an alkaline electrolyte was studied using cyclic voltammetry. It is shown that based on the analysis of CVA curves, CNTS can be divided into two groups-with the Faraday and non-Faraday character of the current electrode processes. The contribution of the non-Faraday component prevails when carbon nanotubes synthesized on Ni/Mg and Co-Mo/Al2O3-MgO catalysts are used as electrode materials. Oxidative functionalization of CNTs of this type is appropriate and contributes to the improvement and stabilization of capacitance properties during cycling. The positive influence of metal oxide catalyst admixtures on the properties of electrode materials was also noted. Therefore, ozone oxidation is a promising way to functionalize CNTs for their subsequent use as electrode materials for electrochemical capacitors.


Author(s):  
E. A. Burakova ◽  
G. S. Besperstova ◽  
M. A. Neverova ◽  
A. G. Tkachev ◽  
N. A. Chapaksov ◽  
...  

In this paper, we studied the effect of heat treatment on the texture characteristics of Co-Mo/Al2O3, a catalyst for the synthesis of carbon nanotubes (CNTs). It has been experimentally proved that the heat treatment conditions at the stage of obtaining the metal oxide catalyst have a significant effect not only on its morphology, but also on its activity in the process of synthesis of CNTs. It was found that the implementation of the heat treatment of the starting components in one stage (decomposition) allows to obtain a catalytic system with a specific surface of ~ 14 ? 26 m2/g and a specific yield of ? ~ 5.2 ? 9.4 gС/gcat, and in two stages (decomposition / calcination) - Scat ~ 30 ? 147 m2/g and ? ~ 18.6 ? 30.0 gС/gcat. The smallest degree of defectiveness (ID / G ~ 0.53 ? 0.72) includes CNTs synthesized on a catalyst formed as a result of thermal changes for 10 min at 350 ° C and calcination at 500 °C, the diameter of the nanotubes is 15 ? 19 nm. The use of a metal oxide catalyst during the synthesis of CNTs, which has been calcined at higher temperatures (700 °C and above), leads to an increase in the speed and degree of defectiveness of the resulting nanostructures. Thus, the introduction of an additional heat treatment stage — calcination in the process of obtaining the Co-Mo/ Al2O3 catalyst — makes it possible to flexibly control the quality parameters of not only the formed metal oxide systems, but also the CNTs synthesized on them.


Author(s):  
Caiqing He ◽  
Yunnen Chen ◽  
Lin Guo ◽  
Ruoyu Yin ◽  
Tingsheng Qiu

2005 ◽  
Vol 100 (3-4) ◽  
pp. 271-276 ◽  
Author(s):  
Vasant R. Choudhary ◽  
Kartick C. Mondal ◽  
Ajit S. Mamman ◽  
Upendra A. Joshi

2019 ◽  
Vol 122 ◽  
pp. 313-319 ◽  
Author(s):  
Wasi Ur Rahman ◽  
Anam Fatima ◽  
Abdul Hakeem Anwer ◽  
Moina Athar ◽  
Mohammad Zain Khan ◽  
...  

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