Predicted tenfold increase of hydrogen solubility in water under pore confinement

Underground hydrogen storage in geological formations has gained interest as a potential solution for the global energy transition. The change of hydrogen solubility in underground confinement is a key challenge for safety and efficiency, yet there is few knowledge on hydrogen solubility under nanoconfinement in clays. Here we used molecular dynamic simulations to study hydrogen solubility in water at realistic storage conditions under the confinement of kaolinite. We find a solubility enhancement of tenfold under nanoscale confinement compared with that in the bulk for both hydrophobic and hydrophilic systems. Mechanisms driving this oversolubility are discussed.