Simulations on methane uptake in tunable pillared porous graphene hybrid architectures

In this article, 3D pillared carbon nanotube (CNT)-porous graphene (PG) nanomesh architectures are computationally investigated as methane storage nanocontainer. The purpose of this article is to screen the configurations of 3D pillared CNT-PG materials and to select the optimal one for maximizing the methane storage capacity. Molecular mechanics (MM) calculations and MD simulations are executed to depict the structural characteristics and methane adsorption properties. The calculated structural parameters coincide well with the empirical conclusions. The methane adsorption simulations are systematic investigated as a function of geometry variables such as PG interlayer spacing, distance of CNTs, and the number of PG sheets in a wide range of pressure. The average adsorption energy of methane in different configurations is concentrated between 2 and 4 kcal mol^-1. The results revealed that the applications of 3D CNT-PG models can significantly enhance methane adsorption performance in comparison to pillared graphene: the maximum amount of adsorbed methane of 3D CNT-PG displays 21.3 mmol/gr (interlayer spacing of 1.2 nm and bilayer PG), which is about 25% higher than that of pillared graphene. Meanwhile, the deformation of (6, 6) carbon nanotubes can significantly improve the methane storage capacity. This provides a viable structure modification method, which is suitable for enhancement of methane storage.