Open carbon nanocones as candidates for gas storage

Abstract

In this Article, we investigate hydrogen, methane, and neon encapsulation and adsorption in open carbon nanocones. We exploit the 6-12 Lennard-Jones potential function and the continuous approximation to model the surface binding energies and the molecular forces between these gases and carbon nanocones of varying vertex angle and length. Our results show that for a hydrogen or methane molecule, or neon atom, interacting with a carbon nanocone the binding energies of the respective systems are minimized when the gas is encapsulated inside the cone. However, we find that for the shorter carbon nanocones, there is a higher energy barrier preventing methane encapsulation in the nanocone. The present modeling indicates that for the particular apex angle of 112.9° the optimal minimum energy storage for the gases occurs in a nanocone of radius 7.1052 Å and of length 4.7126 Å. Our results agree with recent results suggesting that gas adsorption in carbon nanocones is more favorable at lower temperatures. Overall, our results are in very good agreement with other theoretical studies and molecular dynamics simulations and show that carbon nanocones might be good candidates for gas storage. However, the major advantage of the approach here is the derivation of explicit analytical formulas from which numerical results for varying physical scenarios may be readily obtained. © 2011 American Chemical Society.