Study the stability of Si, Ge, Fe and Co in the interior surface of metallic carbon nanotube for hydrogen storage

In this article, we have performed calculations for studying the stability of the carbon group elements such as Si and Ge and also the magnetic elements like Fe and Co via first principle investigations. We found that Si and Ge decoupled from the interior surface of carbon nanotubes, this fact was independent in curvature, radius, conductivity and numbers of atoms in the carbon nanotubes. But the magnetic elements bonded to the surface of the tube via electronegativity factor. The binding energy calculated for Co is -3.82 eV which is more stable than that of Fe (-2.65 eV) due to decrease more in its magnetization. The magnetization of Fe and Co changed from 4.00 μ_B to 3.40 μ_B and 3.00 μ_B to 1.75μ_B respectively. Finally, we came to conclusion that carbon group elements are favorable for hydrogen absorption inside the carbon nanotube whereas the magnetic elements are suitable for hydrogen adsorption.