Molecular dynamics simulation of hydrogen adsorption characteristics on activated carbon at liquid helium temperatures ranging from 10 K to 50 K

Based on graphite microelement, four activated carbon models with different pore structures were constructed. Grand canonical Monte Carlo (GCMC) and molecular dynamics (MD) simulations were applied to investigate the hydrogen adsorption behavior of these models within a temperature range of 10 K to 50 K. Adsorption sites, radial distribution functions, and mean square displacements were analyzed to gain insights into this process. The adsorption behavior of hydrogen on activated carbon was analyzed. Additionally, the changes in adsorption capacity and heat under varying temperatures and pressures were analyzed. The findings indicate that activated carbon mainly adsorbs hydrogen in the form of monolayer adsorption. As the temperature increases, both the adsorption amount and heat gradually decrease. At pressures under 100 kPa, the adsorption rate increases, while saturation is observed at pressures exceeding 100 kPa. The findings provide insight into the physical mechanisms of low-temperature hydrogen adsorption on activated carbon and offer a theoretical foundation for improving hydrogen adsorption performance of the low-temperature pumping arrays in future fusion reactor N-NBI systems.