Grand canonical Monte Carlo simulation of hydrogen physisorption in Li- and K-doped single-walled silicon carbide nanotube

Hydrogen adsorption was investigated in Liand K-doped single-walled silicon carbide nanotubes (SWSiCNT) by applying the grand canonical Monte Carlo simulation. Our results depict that hydrogen storage increases as a function of pressure at fixed temperature. We considered seven doping sites on the nanotube. The results indicate that except for some doping sites, hydrogen adsorption in Li- and K-doped SWSiCNT is more than in SWSiCNT without doping. Another observation is that the hydrogen physisorption in K-doped SWSiCNT is more than that in Li-doped SWSiCNT. The hydrogen adsorption in Li- and K-doped single-walled silicon carbide nanotube arrays (SWSiCNTAs) have also been calculated and illustrate that K-doped SWSiCNTAs have more hydrogen adsorptivity than Li-doped SWSiCNTAs which is in contrast to the obtained results in carbon nanotubes arrays. In this study, we plotted the energy of hydrogen adsorption to confirm the adsorption isotherms and then we fit the simulation data into the Langmuir and Langmuir–Freundlich equation. It was found that multi-layer absorptivity occurs prominently more spatially in K-doped SWSiCNT. However in some doped sites, for both Li- and K-doped SWSiCNT, the dominant mechanism was monolayer adsorptivity which was due to low hydrogen adsorption.