Sprung Christoph, Weckhuysen Bert M
Inorganic Chemistry and Catalysis, Debye Institute for Nanomaterials Science, Utrecht University, Universiteitsweg 99, 3584 CG Utrecht (The Netherlands), Fax: (+31) 302511027.
Chemistry. 2014 Mar 24;20(13):3667-77. doi: 10.1002/chem.201303549. Epub 2014 Feb 24.
Confocal fluorescence microscopy was employed to selectively visualize the dispersion and orientation of zeolite ZSM-5 domains inside a single industrially applied fluid catalytic cracking (FCC) catalyst particle. Large ZSM-5 crystals served as a model system together with the acid-catalyzed fluorostyrene oligomerization reaction to study the interaction of plane-polarized light with these anisotropic zeolite crystals. The distinction between zeolite and binder material, such as alumina, silica, and clay, within an individual FCC particle was achieved by utilizing the anisotropic nature of emitted fluorescence light arising from the entrapped fluorostyrene-derived carbocations inside the zeolite channels. This characterization approach provides a non-invasive way for post-synthesis characterization of an individual FCC catalyst particle in which the size, distribution, orientation, and amount of zeolite ZSM-5 aggregates can be determined. It was found that the amount of detected fluorescence light originating from the stained ZSM-5 aggregates corresponds to about 15 wt %. Furthermore, a statistical analysis of the emitted fluorescence light indicated that a large number of the ZSM-5 domains appeared in small sizes of about 0.015-0.25 μm(2), representing single zeolite crystallites or small aggregates thereof. This observation illustrated a fairly high degree of zeolite dispersion within the FCC binder material. However, the highest amount of crystalline material was aggregated into larger domains (ca. 1-5 μm(2)) with more or less similarly oriented zeolite crystallites. It is clear that this visualization approach may serve as a post-synthesis quality control on the dispersion of zeolite ZSM-5 crystallites within FCC particles.
采用共聚焦荧光显微镜选择性地观察单个工业应用的流化催化裂化（FCC）催化剂颗粒内ZSM-5沸石域的分散和取向。大尺寸的ZSM-5晶体与酸催化的氟苯乙烯齐聚反应一起作为模型系统，用于研究平面偏振光与这些各向异性沸石晶体的相互作用。通过利用沸石通道内捕获的源自氟苯乙烯的碳正离子发出的荧光的各向异性性质，实现了在单个FCC颗粒内区分沸石与粘结剂材料，如氧化铝、二氧化硅和粘土。这种表征方法为单个FCC催化剂颗粒的合成后表征提供了一种非侵入性方法，通过该方法可以确定ZSM-5沸石聚集体的尺寸、分布、取向和数量。发现源自染色的ZSM-5聚集体的检测到的荧光量约为15 wt%。此外，对发出的荧光的统计分析表明，大量的ZSM-5域尺寸较小，约为0.015 - 0.25μm²，代表单个沸石微晶或其小聚集体。这一观察结果表明FCC粘结剂材料内沸石的分散程度相当高。然而，最高量的晶体材料聚集形成较大的域（约1 - 5μm²），其中沸石微晶的取向或多或少相似。显然，这种可视化方法可作为ZSM-5沸石微晶在FCC颗粒内分散的合成后质量控制手段。
