Hello all,
Kindly, what is effect of hydrogen atoms which are added to the dangling bond of carbon in CNT on their properties ?
With warm regard
Carbon nanotubes (CNT) are good hydrogen gas adsorbents. One way to store hydrogen is by adsorbing the H2 atoms on the surface of the carbon. Since it is an adsorption process (i.e., a physical process), there are no chemical reaction involved and there are no changes to the carbon structure.
The adsorbed hydrogen atoms can be adsorbed by heating the CNTs.
Hope this helps answer your question.
Professor Yehia Khalil
Yale University
USA
Dear Fouad,
Your question can be answered from two sides: one is about surface treatment/functionalization of CNTs that plays a key role when a stable suspension is going to be prepared. We can state that lack of hydrogen bonding results in agglomeration of CNTs in aqueous media.
The storage of hydrogen by various new structural forms of carbon is another side. The large available volume, particularly in the cavities inside the single walled carbon nanotubes (SWCNTs), can be used for hydrogen storage. Having said that, understanding the adsorption mechanism is a key to predict the maximum storage capacity and to develop a road map for the development of the carbon CNT-based hydrogen storage vehicle.
Hope it helps!
Best,
I believe that atomic hydrogen being very unstable ( would tend to recombine with another hydrogen atom to form molecule) adsorption is temporary. If there is a hydrogen absorber or a hydride former near by where the atomic hydrogen is generated it will be stored as a hydride. The stability of this hydride depends on the stability of the absorbing material. However gaseous hydrogen can be adsorbed in CNT and desorbed by heating.
how about band gap? In case of graphene, when hydrogen atoms are added onto the edge of graphene, its bandgap is controlled. This phenomenon was published in Science.
Carbon Nanotubes are one of the most controversial and notorious topics in hydrogen storage research since it is a story full of unsubstantiated claims. They are not at all particularly good in storing hydrogen since adsorption more or less scales directly with surface area. E.g., High-surface Activated Carbon performs way better at cryogenic conditions.
If generally interested in hydrogen storage materials and the underlying mechanisms, please find attached a comprehensive review in "Angewandte".
Also, just recently, an important case study on the research history of hydrogen storage in nanotubes over the last two decades was published by Broom and Hirscher in "Energy & Environmental Science". Please find this highly signfcant paper attached below.
http://pubs.rsc.org/en/content/articlelanding/2016/ee/c6ee01435f#!divAbstract
Article Chemical and Physical Solutions for Hydrogen Storage
What are the effects of hydrogen in the carbon nano-tubes formation?
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