Ti-containing hollownest-structured zeolite (Ti-HSZ), constructed by the highly intergrowth of MWW lamellar crystals, has been proven to show excellent catalytic performance in the epoxidation of alkenes due to its highly exposed Ti catalytic active sites and unique hollownest morphology. However, up to date, only piperidine is reported to act as the structure directing agent of MWW crystalline phase for the formation of Ti-HSZ, which has limited its application in a wider range. In this work, Ti-HSZ has been successfully synthesized by using dual templates, including hexamethyleneimine as main template and dicyclohexylamine (or piperidine) as secondary template. Systematical experiments, including composition of synthetic gel, rotation rate of autoclave, and time of crystallization, have been conducted to explore the optional synthesis conditions of Ti-HSZ catalyst with high catalytic performance. It is found that, compared with HMI as solely template, the usage of dual templates HMI/PI or HMI/DCHA is important for the synthesis of Ti-HSZ material, which has important influence on its catalytic performance. In addition, the ratio of main template and secondary template also plays an important role on the catalytic activity of Ti-HSZ catalyst. Moreover, Ti-HSZ material prepared by dual templates owes good recycling stability. This work provides a new route to synthesize Ti-HSZ materials with high catalysis activity.

中文翻译：

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双模板合成高效催化活性含钛空心巢结构沸石

由MWW层状晶体高度共生构成的含钛空心巢结构沸石（Ti-HSZ）由于其高度暴露的Ti催化活性位点和独特的空巢形貌，已被证明在烯烃环氧化反应中表现出优异的催化性能。然而，迄今为止，只有哌啶被报道可以作为MWW晶相的结构导向剂来形成Ti-HSZ，这限制了其更广泛的应用。本工作采用双模板法成功合成了Ti-HSZ，其中六亚甲基亚胺为主模板，二环己胺（或哌啶）为次模板。通过合成凝胶组成、高压釜转速、结晶时间等系统实验，探索高催化性能Ti-HSZ催化剂的合成条件。研究发现，与HMI作为单一模板相比，使用双模板HMI/PI或HMI/DCHA对于Ti-HSZ材料的合成具有重要意义，对其催化性能有重要影响。此外，主模板和次模板的比例对Ti-HSZ催化剂的催化活性也起着重要作用。此外，双模板法制备的Ti-HSZ材料具有良好的回收稳定性。该工作为合成具有高催化活性的Ti-HSZ材料提供了一条新途径。