Investigation of Silicon Model Nanotubes as Potential Candidate Nanomaterials for Efficient Hydrogen Storage: A Combined Ab Initio/Grand Canonical Monte Carlo Simulation Study

Abstract

Grand canonical Monte Carlo (GCMC) simulations combined with ab initio QM calculations were employed to study the adsorption capacity of H 2 in single-walled silicon nanotubes (SWSiNTs) of a hypothetical armchair structural model. The interaction energy of H 2 with a graphite-like sheet from the surface of a single SiNT obtained from the QM calculations was fitted to an accurate potential function used to simulate the system. This theoretical approach is also used in SWCNTs of similar characteristics and at the same thermodynamic states. The GCMC simulation of NT bundles with H 2 showed enhancement of H 2 adsorptivity of SiNTs, as compared with CNTs. Concretely, the (14, 14) SWSiNTs present remarkable percentage improvement of 100, 70, 44, and 25% in the gravimetric (weight percent) adsorption of H 2 at 293 K and 0.1, 1.0, 5.0, and 10.0 MPa, respectively, as compared with isodiameter (22, 22) CNTs. This is attributed to the stronger attractive interaction of H 2 with SiNTs as compared to CNTs, found from the first principle calculations.