TY  - JOUR
AU  - Liang, Zhikai
AU  - Jiang, Zhenxue
AU  - Ostadhassan, Mehdi
AU  - Zhu, Guangyou
AU  - Li, Zhuo
AU  - Arif, Muhammad
PY  - 2026
TI  - Maturity-controlled competitive adsorption of CO2-H2 and CH4-H2 gas mixtures in shale kerogen nanopores
JO  - Advances in Geo-Energy Research
SN  - 2207-9963
SP  - 259
EP  - 276
VL  - 20
IS  - 3
AB  - Organic-rich shales present significant potential for underground hydrogen storage, yet our understanding of the interactions of H2 with CH4 and CO2 in kerogen-hosted nanopores remain insufficient. This study constructs and validates macromolecular models of high-maturity and overmature kerogens via combining solid-state carbon-13 nuclear magnetic resonance spectroscopy, Fourier-transform infrared spectroscopy, and X-ray photoelectron spectroscopy. Grand canonical Monte Carlo and molecular dynamics simulations are performed, which reveal that kerogen maturity controls the competitive adsorption and diffusion of methane/hydrogen and carbon dioxide/hydrogen mixtures by regulating nanopore structure and surface chemical heterogeneity. Compared with high-maturity kerogen, overmature kerogen shows stronger confinement and a more pronounced near-surface enrichment of CH4 and especially CO2, which reduces the effective storage space available for H2. Mechanistically, CH4/H2 competition is driven by van der Waals interactions, whereas CO2/H2 competition is dominated by stronger electrostatic and inductive interactions, establishing a thermodynamic affinity order. The radial distribution functions and interaction energies are measured, which confirm that CH4 and CO2 monopolize high-energy surface sites, relegating H2 to a weakly adsorbed, bulk-like state. Although H2 exhibits the weakest adsorption affinity, its high mobility suggests a stronger migration tendency and potential leakage risk, which should be considered when evaluating long-term containment security during underground hydrogen storage. Overall, this study reveals that maturity-controlled coupling exists between kerogen structure, competitive adsorption and gas transport, providing molecular-scale insights into hydrogen storage security, injectivity, leakage risk, and recovery in organic-rich shale reservoirs.
UR  - https://doi.org/10.46690/ager.2026.06.07
DO  - 10.46690/ager.2026.06.07