Modeling adsorption-based hydrogen storage in nanoporous activated carbon beds at moderate temperature and pressure

Abstract

This study explores the enhancement of hydrogen storage efficiency in four nanoporous activated carbon using a self-developed adsorption model. Results reveal that, at the macroscopic level, decreasing the temperature, and increasing the pressure, velocity, and bed porosity significantly enhance hydrogen adsorption capacity. At the microscopic level, material properties, including micropore and mesopore volumes and specific surface area are critical for influencing the hydrogen storage capacity. The findings indicate that increasing the micropore-to-total pore volume ratio (from 0.8392 to 0.886) and surface area (from 958 to 2280 m²/g) enhances storage efficiency (from 1.2 to 1.9 wt%) at 298 K, 9 MPa. Notably, AC-800 demonstrates superior hydrogen storage capacity (1.9 wt%) due to its well-developed micropores (0.94 cm³/g) enabling efficient H₂ adsorption, and its moderate mesopores (0.12 cm³/g) providing storage capacity and facilitating compression. This work underscores the need to optimize macro and micro-scale parameters to maximize hydrogen storage in activated carbon beds.