Defect-Guided Synthesis of Hierarchical Sn-B-Beta Zeolite with Highly Exposed Sn Sites.
Defect-Guided Synthesis of Hierarchical Sn-B-Beta Zeolite with Highly Exposed Sn Sites.
复制标题
DOI：
10.1021/acs.inorgchem.2c01673
复制
发表时间：
2022-07
影响因子：
4.6
通讯作者：
Lu Fang;Siyang Yan;Huifang Wu;Mingrui Wang;Teng Du;Tianlong Wang;Jiaxu Liu;C. Meng;
中科院分区：
文献类型：
--
作者：
Lu Fang;Siyang Yan;Huifang Wu;Mingrui Wang;Teng Du;Tianlong Wang;Jiaxu Liu;C. Meng;
选择性地将活性中心锚定在外表面上以形成高度暴露的酸位点是沸石催化剂合成中非常理想但具有挑战性的任务。在此，缺陷引导的蚀刻-再生长策略被合理地设计用于在Sn-B-β的外表面上容易地定位Sn刘易斯酸位点，同时制造双功能分级结构。合成是通过水热处理的原样B-Beta（未经煅烧），它具有固有的缺陷的结构，锡源和碱性有机结构导向剂（SDA）。在中等SDA浓度下，在封闭的Sn沟道的情况下，这种SDA触发的蚀刻再生长将沿着缺陷限定的路径进行，这确保Sn选择性地锚定在外表面上。此外，该方法专门引入了四面体配位框架Sn与开放的Sn网站作为占主导地位的物种。单糖和二糖在乙醇中的异构化在不同的Sn-β催化剂上证明了具有高度暴露和协同酸位点的分级结构的突出优势。
Selectively anchoring active centers on the external surface for forming highly exposed acid sites is a highly desirable but challenging task in zeolite catalyst synthesis. Herein, a defect-guided etching-regrowth strategy is rationally designed for facilely positioning Sn Lewis acid sites on the outer surface of the Sn-B-Beta while fabricating a bifunctional hierarchical structure. The synthesis was conducted by hydrothermal treatment of the as-made B-Beta (uncalcined), which has intrinsic defects of the BEA structure, with Sn source and basic organic structure directing agent (SDA). Under a moderate SDA concentration, with blocked micropore channels, such SDA-triggered etching-regrowth will proceed along the defect defined pathway, which ensures Sn selectively anchored on the external surface. Moreover, this methodology has exclusively introduced tetrahedrally coordinated framework Sn with open Sn sites as the predominated species. Mono- and disaccharide isomerizations in ethanol over different Sn-Beta catalysts proved the prominent advantages of the hierarchical structure with highly exposed and synergetic acid sites.