Low-temperature hydrogen-graphite system revisited: Experimental study and Monte Carlo simulation

Hydrogen adsorption by microporous carbon materials attracts much attention for the past few decades, which has been stimulated by growing interest in hydrogen storage. Numerous studies of this topic based on molecular simulation technique have been reported. However, in many cases, the reliability of the results obtained with numerical methods is insufficient, which is a consequence of poor reference data used for fitting parameters of the fluid-fluid and fluid-solid potentials. This study is devoted to a detailed experimental investigation of the hydrogen-graphite system and its modeling with a kinetic Monte Carlo method at temperatures from 20 to 77 K and the bulk pressure from 0.1 Pa to 100 kPa. We found that the best fit of the bulk hydrogen equation of state corresponds to the 10-6 Lennard-Jones potential with the temperature dependent parameters to account for the quantum effects. The experimental hydrogen adsorption isotherms on the graphite surface were fitted with a high accuracy, which constitutes a firm basis of subsequent simulation of hydrogen adsorption in various nanoporous carbons and their pore size distribution analysis using a kernel generated with the developed approach.