Direct Volumetric Measurement of Gas Oversolubility in Nanoliquids: Beyond Henry’s Law

The properties of condensed matter are strongly affected by confinement and size effects at the nanoscale. Herein, we measured by microvolumetry the increased solubility of H 2 in a series of solvents (CHCl 3 , CCl 4 , n ‐hexane, ethanol, and water) when confined in the cavities of mesoporous solids (γ‐alumina, silica, and MCM‐41). Gas/liquid solubilities are enhanced by up to 15 times over the corresponding bulk values for nanoliquid sizes smaller than 15 nm as long as gas/liquid interfaces are mesoconfined in a porous network. Although Henry’s law constant apparently no longer applies under these confinement, the concentration of dissolved H 2 still increases linearly with increasing pressure in the range 1–5 bar. We discuss the role and main implications of surface excess concentrations at mesoconfined gas/liquid interfaces in enhancing gas solubility.