The chemical state and acidity of ceria incorporated in hierarchical zeolites have been successfully tuned due to the presence of hierarchical structures of zeolite nanosheets and interaction between ceria and...
Over the past decades, the catalytic cracking catalysts for hydrocarbon oil upgrading have been extensively developed to increase the yield of light olefins. In this context, we report the fabrication of the core‐shell ZSM‐5@aqueous miscible organic‐layered double hydroxides prepared by the growth of layered double hydroxides (LDH) precursors on zeolite surfaces. The deposited LDH results in a decrease of the number of strong Brønsted acid sites on zeolite surfaces and its transformation at high temperature leads to produce the highly dispersed metal oxides deposited on external surfaces of zeolites. Therefore, the acid‐base properties of designed surfaces are modified, eventually resulting in the suppression of competing hydride transfers and further side reactions. As a result, there is a significant enhancement in light olefins production compared with the pristine zeolite. In addition, the designed catalysts exhibit high recycling stability and reusability. This first example opens up the new perspectives for the development of modified acid‐base zeolites using zeolite@aqueous miscible organic‐layered double hydroxides for the catalytic upgrading of hydrocarbons.
Various metals including Sn, Ge, and Zr have been successfully incorporated into the MFI nanosheets via a one-pot synthesis. The as-synthesized zeolites exhibit high external surface area and mesopore volume without large metal oxides aggregated on zeolite surfaces. Interestingly, the successful introduction of heteroatoms in MFI nanosheets can be confirmed by shifted XRD peaks corresponding to the unit cell expansion due to the replacement of metals into the framework. In addition, the UV-Vis absorbance spectra reveal that at the suitable metal loading the incorporated tetrahedral coordination of metal species in the zeolite framework has been obtained. To illustrate the benefits of the prepared catalysts, the glucose isomerization to fructose was carried out in a water/dioxane system. Obviously, the SnMFI-NS samples, containing the high dispersion of metal isomorphous species demonstrate the outstanding catalytic behavior in term of fructose selectivity (> 85 %).
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