Silicon nanotube as a promising candidate for hydrogen storage: From the first principle calculations to grand canonical Monte Carlo simulations

We employ a multiscale, theoretical method, which combines the first-principle calculation and a grand canonical Monte Carlo (GCMC) simulation, to predict the adsorption capacity of hydrogen in silicon nanotube (SiNT) arrays at T = 298 K in the pressure range from 1 to 10 MPa. In the multiscale method, the binding energy obtained from the first-principle calculation is used as an input in the GCMC simulation. It is found from the first-principle calculation that the SiNT arrays exhibit much stronger attraction to hydrogen both inside and outside SiNTs, compared to the isodiameter carbon nanotubes (CNTs). The subsequent GCMC simulations indicate that the SiNT arrays present distinct improvements of 106%, 65%, and 52% in the gravimetric adsorption capacity of hydrogen at P = 2, 6, and 10 MPa, respectively, compared to the isodiameter CNTs. This suggests that the SiNT array is a promising candidate for hydrogen storage.