Improving the stability of porous materials for practical applications is highly challenging. Aluminosilicate zeolites are utilized for adsorptive and catalytic applications, wherein they are sometimes exposed to high-temperature steaming conditions (∼1000 °C). As the degradation of high-silica zeolites originates from the defect sites in their frameworks, feasible defect-healing methods are highly demanded. Herein, we propose a method for healing defects to create extremely stable high-silica zeolites. High-silica (SiO2/Al2O3 > 240) zeolites with *BEA-, MFI-, and MOR-type topologies could be stabilized by significantly reducing the number of defect sites via a liquid-mediated treatment without using additional silylating agents. Upon exposure to extremely high temperature (900–1150 °C) steam, the stabilized zeolites retain their crystallinity and micropore volume, whereas the parent commercial zeolites degrade completely. The proposed self-defect-healing method provides new insights into the migration of species through porous bodies and significantly advances the practical applicability of zeolites in severe environments.

Encapsulating metal nanoclusters into zeolites combines the superior catalytic activity of the nanoclusters with high stability and unique shape selectivity of the crystalline microporous materials. The preparation of such bifunctional catalysts, however, is often restricted by the mismatching in time scale between the fast formation of nanoclusters and the slow crystallization of zeolites. We herein demonstrate a novel strategy to overcome the mismatching issue, in which the crystallization of zeolites is expedited so as to synchronize it with the rapid formation of nanoclusters. The concept was demonstrated by confining Pt and Sn nanoclusters into a ZSM-5 (MFI) zeolite in the course of its crystallization, leading to an ultrafast, in situ encapsulation within just 5 min. The Pt/Sn-ZSM-5 exhibited exceptional activity and selectivity with stability in the dehydrogenation of propane to propene. This method of ultrafast encapsulation opens up a new avenue for designing and synthesizing composite zeolitic materials with structural and compositional complexity.

Proton conduction in alkali metal ion-exchanged porous ionic crystals A[CrO(OOCH)(etpy)][α-SiWO]·nHO [I-A] (A = Li, Na, K, Cs, etpy = 4-ethylpyridine) is investigated. Single crystal and powder X-ray diffraction measurements show that I-A possesses analogous one-dimensional channels where alkali metal ions (A) and water of crystallization exist. Impedance spectroscopy and water diffusion measurements of I-A show that proton conductivities are low (10-10 S cm) under low relative humidity (RH), and protons mostly migrate as HO with HO as vehicles (vehicle mechanism). The proton conductivity of I-A increases with the increase in RH and is largely dependent on the types of alkali metal ions. I-Li shows a high proton conductivity of 1.9 × 10 S cm (323 K) and a low activation energy of 0.23 eV under RH 95%. Under high RH, alkali metal ions with high ionic potentials (e.g., Li) form a dense and extensive hydrogen-bonding network of water molecules with mobile protons at the periphery, which leads to high proton conductivities and low activation energies via rearrangement of the hydrogen-bonding network (Grotthuss mechanism).