Nanoconfined Water in Pillared Zeolites Probed by H Nuclear Magnetic Resonance.

Here, we report the results of our H nuclear magnetic resonance study of the dynamics of water molecules confined in zeolites (mordenite and ZSM-5 structures) with hierarchical porosity (micropores in zeolite lamella and mesopores formed by amorphous SiO in the inter-lamellar space). H nuclear magnetic resonance (NMR) spectra show that water experiences complex behavior within the temperature range from 173 to 298 K. The temperature dependence of H spin-lattice relaxation evidences the presence of three processes with different activation energies: freezing (about 30 kJ/mol), fast rotation (about 10 kJ/mol), and translational motion of water molecules (23.

Manifesting Epoxide and Hydroxyl Groups in XPS Spectra and Valence Band of Graphene Derivatives.

The derivatization of graphene to engineer its band structure is a subject of significant attention nowadays, extending the frames of graphene material applications in the fields of catalysis, sensing, and energy harvesting. Yet, the accurate identification of a certain group and its effect on graphene's electronic structure is an intricate question. Herein, we propose the advanced fingerprinting of the epoxide and hydroxyl groups on the graphene layers via core-level methods and reveal the modification of their valence band (VB) upon the introduction of these oxygen functionalities.

H NMR Study of the HCaNbO Photocatalyst with Different Hydration Levels.

The photocatalytic activity of layered perovskite-like oxides in water splitting reaction is dependent on the hydration level and species located in the interlayer slab: simple or complex cations as well as hydrogen-bonded or non-hydrogen-bonded HO. To study proton localization and dynamics in the HCaNbO·HO photocatalyst with different hydration levels (hydrated-α-form, dehydrated--form, and intermediate-β-form), complementary Nuclear Magnetic Resonance (NMR) techniques were applied. H Magic Angle Spinning NMR evidences the presence of different proton containing species in the interlayer slab depending on the hydration level.