Zeolite FAU with tunable SiO₂/Al₂O₃ molar ratio has been successfully synthesized in the absence of organic structure‐directing agents (OSDA). Specifically, the addition of zinc species contributes to the feasible and effective adjustment of the framework SiO₂/Al₂O₃ molar ratio between about 4 and 6 depending on the amount of zinc species added in the batch composition. In contrast, a typical OSDA such as tetramethylammonium hydroxide (TMAOH) has a limited effect on the SiO₂/Al₂O₃ molar ratio of the zeolite. The role of zinc species is essential for the crystallization of zeolite FAU with a higher SiO₂/Al₂O₃ molar ratio under the particular synthesis conditions. It is speculated that zinc species may suppress the incorporation of aluminum into the aluminosilicate framework, which is due to the Coulombic repulsive interaction. A higher SiO₂/Al₂O₃ molar ratio is also found to be accompanied by a lower CO₂ adsorption heat for CO₂/CH₄ separation.

中文翻译：

---

具有可调的SiO2 / Al2O3摩尔比的无有机ZnO辅助合成FAU沸石

在没有有机结构导向剂（OSDA）的情况下，已经成功合成了具有可调SiO ₂ / Al ₂ O ₃摩尔比的FAU沸石。具体地，锌物质的添加取决于在批料组合物中添加的锌物质的量，有助于将骨架SiO ₂ / Al ₂ O ₃摩尔比在约4至6之间的可行和有效的调节。相反，典型的OSDA例如氢氧化四甲基铵（TMAOH）对沸石的SiO ₂ / Al ₂ O ₃摩尔比具有有限的影响。锌的作用对于具有较高SiO的FAU沸石的结晶至关重要在特定合成条件下₂ / Al ₂ O ₃摩尔比。据推测，由于库仑排斥相互作用，锌物质可抑制铝结合到铝硅酸盐骨架中。还发现更高的SiO ₂ / Al ₂ O ₃摩尔比伴随着更低的CO ₂ / CH ₄分离的CO ₂吸附热。