We studied liquid water confined within nanopores which present a high level of hydrophobicity thanks to a new method of synthesis. We found that the liquid state persists down to temperatures much lower than in the bulk and in hydrophilic materials of comparable sizes, allowing us to define a thermodynamic limit for the melting/crystallization of water.

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We report 2 H NMR spin-lattice relaxation times T 1 and spectra of two fragile molecular glass forming liquids, deuterated o-terphenyl-d 14 (OTP) and toluene-d 5, confined in a nanoporous SBA-15 type matrix with a pore diameter of 7.1-nm size. We compare these results with bulk data of several glass formers. The temperature dependence of T 1 allows us to differentiate type A (without secondary β process) from type B glass formers (with β process). We find that the R process of both OTP (type A) and toluene (type B) in confinement is governed by a broad heterogeneous distribution of correlation times, not seen in the bulk. Additionally, there is evidence that the β process in toluene changes under confinement conditions, where it exhibits a distribution of spin-lattice relaxation times that is substantially broadened toward faster times. In contrast, the excess wing for OTP is not altered in confinement.

Measurement of H(2) production from electron irradiation (10 MeV) on SBA-15 materials has shown that adsorbed water is attacked preferentially. Silanol groups are only attacked when they are in the majority with respect to adsorbed water, however they are much less efficient at producing H(2). The comparison between water content before and after electron irradiation and the corresponding H(2) production indicates that water desorption is the main route to adsorbed water loss for SBA-15 materials. On the other hand, surface silanol groups are more susceptible to attack, leading to H(2) production when SBA-15 samples have undergone extensive thermal treatment. Electron irradiation of SBA-15-Cu materials has shown that the presence of Cu(II) on the surface reduces and inhibits the production of H(2.) This inhibiting power affects adsorbed water bonded to grafted copper but not surface silanol groups.

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