Here, we report the results of our ¹H 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 SiO₂ in the inter-lamellar space). ¹H nuclear magnetic resonance (NMR) spectra show that water experiences complex behavior within the temperature range from 173 to 298 K. The temperature dependence of ¹H 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 (23.6 and 26.0 kJ/mol for pillared mordenite and ZSM-5, respectively). For translational motion, the activation energy is markedly lower than for water in mesoporous silica or zeolites with similar mesopore size but with disordered secondary porosity. This indicates that the process of water diffusion in zeolites with hierarchical porosity is governed not only by the presence of mesopores, but also by the mutual arrangement of meso- and micropores. The translational motion of water molecules is determined mainly by zeolite micropores.

In this study, lamellar MFI (Mobile Five-membered ring Intergrowth) zeolites pillared with TiO₂ were synthesized using tetraethyl orthotitanate (TEOTi) as titanium precursor and evaluated as photocatalysts for Rhodamine B (RhB) degradation under UV irradiation. The materials were characterized by X-ray diffraction (XRD), UV–Vis spectroscopy, N₂ adsorption–desorption, photoluminescence spectroscopy (PL), and transmission electron microscopy (TEM). XRD confirmed the preservation of the lamellar MFI structure and the formation of anatase TiO₂ pillars within the interlayer space. The composites exhibited hierarchical micro/mesoporosity, high surface areas (>320 m² g⁻¹), and mesopore sizes of approximately 4.1–4.2 nm. Photocatalytic experiments revealed that the incorporation of TiO₂ into the lamellar MFI framework significantly enhanced the degradation kinetics of RhB compared with bare TiO₂. The apparent pseudo-first-order rate constants followed the order MFIPTi-6 > MFIPTi-3 > MFIPTi-12 > TiO₂ > MFIPTi-24, with MFIPTi-6 exhibiting the highest activity (k_app = 0.049 min⁻¹), approximately 1.6 times higher than that of pure TiO₂. Scavenger experiments identified hydroxyl radicals as the predominant reactive species involved in the degradation process. TOC (Total Organic Carbon) measurements showed approximately 80% organic carbon removal, while recyclability tests demonstrated stable photocatalytic performance over six consecutive cycles. These results highlight the potential of lamellar TiO₂/MFI composites as efficient and reusable photocatalysts for water treatment applications.