Molecular Simulation of Hydrogen Physisorption and Chemisorption in Nanoporous Carbon Structures

Abstract

The effect of pore morphology on the hydrogen-storage capacity of carbon materials at room temperature (298 K) has been studied using Grand Canonical Monte Carlo (GCMC) molecular simulation. Prototypical pore geometries such as slit pores and nanotubes were considered along with carbon foams and a random disordered carbon structure. Both physisorption and chemisorption models were considered in order to take into account the most favourable adsorption scenarios. Fluid-fluid and fluid-solid interactions were assumed to follow a Lennard-Jones-type potential.It was seen that physisorption alone cannot account for the adsorption of more than a few weight percentages, regardless of the pore morphology. Under physisorption conditions, the simulation results show that carbons with a slitshaped pore geometry are more efficient than other geometries at storing hydrogen, particularly at pore distances which allow the formation of fluid layers commensurate with the pore geometry. Slit pores appear to store a maximum...