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基于丝光沸石骨架结构固有的晶体缺陷特征,提出诱导晶体结构缺陷和由结构缺陷衍生晶内介孔的研究方案。采用三元有机超分子胶束模板剂和两段变温晶化水热法,制备出丝光沸石基多级介孔材料。通过粉末X射线衍射、77K氮吸附–脱附、场发射透射电子显微镜、氨程序升温脱附对合成的介孔材料的晶相、形貌、介孔特征和水热稳定性进行了表征。结果表明:所合成的典型丝光沸石具有较高的相对结晶度,介孔比表面积和介孔体积分别为152.7m2/g和0.163 cm3/g;晶体内介孔在3～50 nm区间呈多级分布;其酸性质与微孔丝光沸石相匹配;水热稳定性较有序介孔材料MCM-41有显著提高。与聚集态纳米沸石组装介孔材料不同,合成的介孔丝光沸石晶体表面上介孔排布密度和尺寸分布缺乏均一性,故而由体相结构缺陷诱导形成的附加介孔呈显著无序状态。
Based on the intrinsic crystal defect characteristics of mordenite framework, a scheme of inducing crystal structure defects and crystal mesopores derived from structural defects was proposed. The mordenite-based multi-stage mesoporous materials were prepared by using ternary organic supramolecular micelle template and two temperature-variable crystallization hydrothermal methods. The crystal phase, morphology, mesopore characteristics and hydrothermal stability of the synthesized mesoporous materials were characterized by powder X-ray diffraction, 77K nitrogen adsorption-desorption, field emission transmission electron microscopy and ammonia temperature-programmed desorption. The results showed that the typical mordenite synthesized had high relative crystallinity, the mesoporous surface area and mesopore volume were 152.7m2 / g and 0.163 cm3 / g, respectively. The mesopores of the crystals were in the range of 3 ~ 50 nm Its acidity is matched with microporous mordenite, and its hydrothermal stability is significantly improved compared with MCM-41, an ordered mesoporous material. Unlike assembled nano-zeolites, mesoporous mesostructured mesoporous mordenite crystals have a lack of homogeneity in the density and size distribution of the mesopores. Therefore, the additional mesopores formed by the structural defects of the bulk phase are markedly disordered.