Dynamics of Guest Water Molecules in Pillared Mordenite Studied by 1H NMR Relaxation

The dynamics of H 2 O molecules confined in mesopores of about 3.4 nm in size, formed by amorphous SiO 2 pillars separating 2D mordenite nanolayers, was probed by 1 H nuclear magnetic relaxation. 1 H nuclear magnetic resonance (NMR) spectra evidence the presence of water with different local surroundings and mobility. The temperature dependence of 1 H spin–lattice relaxation T 1 and relaxation in rotating frame T 1ρ indicate the complex behavior of nanoconfined water that can be characterized by different activation energies: freezing (29 kJ/mol), fast rotation (12 kJ/mol), and translational motion (23.6 kJ/mol).