Hydrogen adsorption on osmium and boron co-doped single walled carbon nanotubes for energy storage: A DFT study

Abstract

The osmium and boron co-doped armchair single walled carbon nanotubes (SWCNTs) have been studied for hydrogen storage using ab-initio method. The calculations have been carried out using Gaussian software with Density functional theory. We have replaced a carbon atom by osmium atom in SWCNT & neighboring carbon atoms are replaced by boron atoms sequentially. In the present work, the hydrogen adsorption ability of osmium/boron co-doped CNTs has been investigated on the basis of bond distances, variation of binding energy, chemical hardness, band gaps, charge distribution and adsorption energies. It is found that osmium/boron co-doping in SWCNTs enhanced the hydrogen storage capacity but increase of boron atom concentration in osmium doped SWCNT reduces the storage ability. The maximum hydrogen adsorption energy was calculated in case of osmium atom decorated single boron atom doped SWCNT (Os-BCNT) i.e. E ads - 0.490 eV. And study reveal that osmium doped CNT (Os-CNT) and osmium/boron co-doped CNT (Os-BCNT) both can efficiently adsorb five hydrogen molecules at 298.15 Kelvin temperature/1 atm pressure. • Modified structural and electrical properties of osmium/boron co-doped SWCNT • Enhanced hydrogen storage capacity of osmium/boron co doped SWCNT. • Effect of boron concentration on hydrogen storage capacity on SWCNT