Grand canonical Monte Carlo simulation on the hydrogen storage behaviors of the cup-stacked carbon nanotubes at room temperature.

The hydrogen uptake of a novel type of cup-stacked carbon nanotubes (CSCNTs) are investigated by the Grand Canonical Monte Carlo simulation at 298 K and 1–10 MPa. The differences of the hydrogen storage behaviors between the truncated cone of CSCNTs and the cylinder of carbon nanotubes (CNTs) are studied. The effects of apex angle and interlayer distance of the truncated cone are also considered. The simulated results show that the hydrogen uptake of the truncated cone is higher than that of the cylinder. Compared with the cylinder, the adsorbed hydrogen molecules of the truncated cone can distribute uniformly. With the decrease of apex angle, the C–H interaction becomes stronger and then the hydrogen uptake increases. CSCNTs with the interlayer distance of 7 Å have the optimum hydrogen uptake. The excessively large interlayer distance will weaken the C–H interaction and result in the decrease of hydrogen uptake. • Hydrogen molecules can be absorbed on the truncated cone uniformly. • Hydrogen uptake of the truncated cone is larger than that of the cylinder. • Truncated cone with apex angle of 19.2° has maximum hydrogen uptake. • Interlayer distance of 7 Å is optimum for the hydrogen storage of CSCNTs. [ABSTRACT FROM AUTHOR]