On the supercritical adsorption of molecular hydrogen and deuterium in microporous carbons

Understanding the adsorption behavior of hydrogen and deuterium in nanoporous carbons is critical for advancing gas storage and separation technologies. In this study, neutron scattering, gas adsorption, and molecular simulations were combined to unravel the complex interplay between pore structure, spatial confinement, and adsorption mechanisms. By simulating the adsorption in realistic 3D molecular structures of nanoporous carbons, preferred adsorption sites were identified, revealing that highly confining geometries—rich in defects—enhance adsorption. Denser carbons exhibit stronger confinement but lower overall uptake due to limited pore space. Despite accounting for isotope-specific effects, significant deviations between simulated and experimental scattering data suggest distinct molecular arrangements, particularly for H2. The findings of this study underscore the need for refined atomistic models incorporating surface chemistry and spin-isomer effects to bridge the gap between experiment and simulation, guiding the design of optimized nanoporous materials for hydrogen storage.