复旦大学唐颐团队报道了超宽pH范围内硅烷醇巢含量可调ZSM-5分子筛纳米片的合成及其催化验证。相关研究成果发表在2024年4月9日出版的《德国应用化学》。

在酸性条件下合成沸石一直是一个挑战。

该文中，研究人员在宽pH范围（4-13）内成功制备了一系列ZSM-5沸石纳米片（Z-5-SCA-X），而不需要额外的补充剂。这一成果是通过从ZSM-5沸石合成体系中提取的具有高度短程有序性，和超小尺寸的ZSM-5分子筛亚晶（Z-5-SC）的聚集结晶实现的。此外，还研究了Z-5-SC的结晶行为，揭示了其在弱碱性和酸性条件（pH＜10）下的非经典结晶过程，以及在强碱性条件（pH≥10）下经典和非经典过程的结合。

特别有趣的是，所得Z-5-SCA-X样品中的硅烷醇巢含量似乎取决于Z-5-SC结晶过程中的pH值，而不是其结晶度。最后，糠醇醚化反应的结果表明，降低硅烷醇巢的浓度显著提高了Z-5-SCA-X沸石的催化性能。在中性和酸性环境中合成沸石而不需要额外的矿化剂的能力，不仅拓宽了传统沸石合成的当前观点，而且为控制沸石催化剂的硅烷醇巢含量提供了一种新的方法。

附：英文原文

Title: Synthesis of ZSM-5 Zeolite Nanosheets with Tunable Silanol Nest Contents across an Ultra-wide pH Range and Their Catalytic Validation

Author: He Li, Jiayu Yu, Ke Du, Wanyi Li, Ling Ding, Wei Chen, Songhai Xie, Yahong Zhang, Yi Tang

Issue&Volume: 2024-04-09

Abstract: Zeolite synthesis under acidic conditions has always presented a challenge. In this study, we successfully prepared series of ZSM-5 zeolite nanosheets (Z-5-SCA-X) over a broad pH range (4 to 13) without the need for additional supplements. This achievement was realized through aggregation crystallization of ZSM-5 zeolite subcrystal (Z-5-SC) with highly short-range ordering and ultrasmall size extracted from the synthetic system of ZSM-5 zeolite. Furthermore, the crystallization behavior of Z-5-SC was investigated, revealing its non-classical crystallization process under mildly alkaline and acidic conditions (pH < 10), and the combination of classical and non-classical processes under strongly alkaline conditions (pH ≥ 10). What's particularly intriguing is that, the silanol nest content in the resultant Z-5-SCA-X samples appears to be dependent on the pH values during the Z-5-SC crystallization process rather than its crystallinity. Finally, the results of the furfuryl alcohol etherification reaction demonstrate that reducing the concentration of silanol nests significantly enhances the catalytic performance of the Z-5-SCA-X zeolite. The ability to synthesize zeolite in neutral and acidic environments without the additional mineralizing agents not only broadens the current view of traditional zeolite synthesis but also provides a new approach to control the silanol nest content of zeolite catalysts.

DOI: 10.1002/anie.202405092

Source: https://onlinelibrary.wiley.com/doi/10.1002/anie.202405092