【摘要】 沸石分子筛是迄今为止应用最广泛,对社会贡献最大的多孔材料.多级孔沸石兼具扩散系数大和活性高的双重优势,是理想的吸附和催化材料.研究发现一类有机小分子致介孔剂如氨基酸、苯酚、氮唑等,通过原位生成氧、氮或碳负离子起到亲核刻蚀作用,一锅法产生沸石晶内介孔.刻蚀调控作用于早期沸石前体,可有效调控沸石结晶度、大小、形貌、多级孔和性能.将温和有机小分子刻蚀剂原位加入沸石合成反应液中,能够克服传统“自下而上”策略中介观模板必须煅烧和“自上而下”策略中沸石骨架结构易于破坏的问题.利用早期沸石前体引入刻蚀与生长的平衡机制和协同作用,可以有效调控沸石结晶度、大小、形貌、多级孔和性能.本研究评论首先简要介绍了多级孔沸石制备的现有策略,随后对原位刻蚀辅助生长策略进行了详细讨论,包括原位刻蚀剂的选择、原位刻蚀辅助的沸石晶化过程机理和优势,最后对原位刻蚀调控多级孔分子筛的应用进行了总结.更多还原

【Abstract】 Zeolite molecular sieve is by far the most widely used porous material with the greatest contribution to society.Hierarchical zeolites, which possess dual advantages of large diffusion coefficient and high activity, are increasingly important as catalysts and adsorbents in many chemical processes. A class of organic mesoporogens named organic mesopore generating agents(OMeGAs), such as amino acids, phenols, and azoles were found to produce intracrystalline mesopores by one pot method, wherein the nucleophilic etching effect of the in-situ generated anions, including oxyanions, nitranions, or carbanions, plays the key role. By adding mild OMeGAs in-situ into the reaction solution of zeolite synthesis, the nucleophilic etching assisted growth could overcome the energy-intensive mesoscale template calcination associated with the “bottom-up” strategy and the zeolite structure destruction of the “top-down” post-synthetic strategy. The interplay between in-situ etching and growth on the early precursor or nuclei has enabled effective control over crystallinity, size, morphology,mesopores, and performance of zeolites. In this account, the existing preparation strategies of hierarchical zeolite are first briefly introduced. Then, the in-situ etching-assisted growth strategies are discussed in detail, including the selection of mild etchant OMeGAs, mechanism and advantages of the etching-assisted zeolite crystallization process. Finally, the application of in-situ etching-manipulated hierarchical zeolite is summarized.更多还原