DFT study on hydrogen adsorption behaviour of armchair and sawtooth structure cup-stacked carbon nanotube walls with B-substituted and Pt-decorated

The hydrogen storage properties of Cup-Stacked Carbon Nanotubes (CSCNTs), which are sawtooth-shaped and armchair-shaped structures with B atom substitutions at different spacings and loaded with Pt atoms, were investigated using density functional theory. The results show that when the spacing of the B atoms is small, the Pt atoms still tend to form clusters due to the interatomic gravitational force between the Pt atoms, which is larger than the attraction between the Pt atoms and the C/B atoms. For the sawtooth-shaped structure, B-atom spacing greater than 7.3 Å, with stabilised isolated Pt atoms loading, and the maximum hydrogen adsorption capacity. In addition, electrostatic potentials, electron localisation function and Weak interaction analysis investigated the mechanism of Pt atom loading. The HOMO-LUMO orbitals and energy gap of the two structures are also compared, and it is found that the armchair-shaped structure has a larger energy gap and a more stable electronic structure.