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.

Characteristics of zeolite formation, such as being kinetically slow and thermodynamically metastable, are the main bottlenecks that obstruct a fast zeolite synthesis. We present an ultrafast route, the first of its kind, to synthesize high-silica zeolite SSZ-13 in 10 min, instead of the several days usually required. Fast heating in a tubular reactor helps avoid thermal lag, and the synergistic effect of addition of a SSZ-13 seed, choice of the proper aluminum source, and employment of high temperature prompted the crystallization. Thanks to the ultra-short period of synthesis, we established a continuous-flow preparation of SSZ-13. The fast-synthesized SSZ-13, after copper-ion exchange, exhibits outstanding performance in the ammonia selective catalytic reduction (NH3 -SCR) of nitrogen oxides (NOx ), showing it to be a superior catalyst for NOx removal. Our results indicate that the formation of high-silica zeolites can be extremely fast if bottlenecks are effectively widened.

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This review attempts to summarize the recently developed strategies to improve the hydrothermal framework stability of zeolites.

Nepheline group materials obtained by a thermal treatment of K2CO3-supported nanosized sodalite are identified as cost-effective materials which show promising activity and durability toward diesel soot combustion.

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We demonstrate morphology dependence of mesoporous silica synthesized in acidic condition via the control of silica hydrolysis and condensation at 4 °C under quiescent acidic condition, and without using any organic cosolvents. Tetramethyl orthosilicates (TMOS) is used as a silica source and cetyltrimethylammonium chloride (CTAC) as the structure directing agent (SDA). Straight fibers of different aspect ratio with pore channels aligned parallel to the fiber axis are synthesized by varying TMOS from the sols of molar compositions 0.17−0.32TMOS:0.22CTAC:9HCl:100H2O. Curved morphologies such as discoids and spheres are prepared by controlling acidity in the sols of molar compositions 0.17TMOS:0.22CTAC:14−16HCl:100H2O. The mesoporous silica particles show BET surface area of 1100−1400 cm3/g, and the mesopore diameter and mesopore volume are in the range of 2.2−2.6 nm and 0.6−0.8 cm3/g, respectively.

SSZ-33 is tested for possible application as a hydrocarbon trap by investigating the temperature-programmed desorption behavior of toluene (used as a probe molecule) and the results are compared to those obtained with zeolites β, Y, mordenite, and ZSM-5. SSZ-33 shows higher adsorption capacity than the other zeolites at the conditions used here, and as well as better hydrothermal stability than zeolite β, and is therefore identified as a promising candidate for use as a hydrocarbon trap in cold-start emission control.