Computational Characterization of Hexagonally Ordered Carbon Nanopipes CMK-5 and Structural Optimization for H2 Storage

We performed grand canonical Monte Carlo (GCMC) simulations to characterize the hexagonally ordered carbon nanopipes CMK-5 and further investigated the adsorptive properties of this material for H-2. The geometrical model from Solovyov et al. was used to characterize the hexagonal structure of the CMK-5 adsorbent. The interactions between a fluid molecule inside and outside the nanopipe and a single layer were calculated by the potential models proposed by Tjatjopoulos et al. and Gordon et al. When the calculated results were fitted to the experimental isotherm of N-2 adsorption at 77 K, the structural parameters of the CMK-5-S material were obtained. To improve H-2 adsorption, we also optimized the structural parameters of CMK-5 material. The maximum excess gravimetric and volumetric uptakes of H-2 in the CMK-5 material with the optimized structural parameters at T = 77 K are 5.8 wt % and 41.27 kg/m(3), which suggest that the CMK-5 material with,in optimized structure is a promising adsorbent for gas adsorption.