Extremely Stable Zeolites Developed via Designed Liquid-Mediated Treatment

Porous materials face limitations in harsh environments due to structural instability. Aluminosilicate zeolites are widely used in catalytic and adsorption processes. However, exposure to high-temperature steam causes degradation. This degradation is linked to defect sites in the zeolite framework. Prior research has shown that high-silica zeolites are especially vulnerable. No prior work had resolved how to stabilize these materials under extreme conditions. That uncertainty drove the need for a new approach. This gap motivated the development of a method to reduce defect sites without external agents.

The aim was to create a method for stabilizing high-silica zeolites under extreme steam conditions. High-silica zeolites are prone to degradation due to framework defects. The challenge is to maintain their structural integrity at high temperatures. A solution was needed that does not rely on silylating agents. The study focused on *BEA-, MFI-, and MOR-type zeolites. These materials are common in industrial applications. The goal was to retain crystallinity and micropore volume under steam. This problem is critical for extending zeolite use in severe environments.

The method involved a liquid-mediated treatment to heal framework defects. No silylating agents were added during the process. The treatment was applied to high-silica zeolites with specific topologies. The zeolites were then subjected to high-temperature steam. The stability was evaluated by measuring crystallinity and micropore volume. The process was tested across a range of temperatures (900-1150 °C). The results were compared to parent commercial zeolites. This approach allowed for a direct assessment of defect reduction effectiveness.

Stabilized zeolites retained crystallinity after exposure to 900-1150 °C steam. The micropore volume was preserved in treated samples. Parent commercial zeolites showed complete degradation under the same conditions. The method significantly reduced the number of defect sites. The SiO₂/Al₂O₃ ratio exceeded 240 in the treated materials. The liquid-mediated treatment did not require external silylating agents. The results suggest that species migration occurs through the porous structure. This finding supports the feasibility of the self-defect-healing method.

The proposed method enables the creation of extremely stable high-silica zeolites. The liquid-mediated treatment reduces defect sites without external agents. Stabilized zeolites retain their structure under extreme steam conditions. The method applies to *BEA-, MFI-, and MOR-type topologies. The results suggest that species migration plays a role in defect healing. This approach advances the practical use of zeolites in severe environments. The authors propose that this method provides new insights into porous material stability. The findings support the potential for broader industrial applications.