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 (gamma-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.