The creation of intergrown layer-like zeolite crystals is one route to form hierarchical zeolites.Faujasite-type(FAU-type)zeolites are among the industrially most important zeolites and the implementation of hierarchi...The creation of intergrown layer-like zeolite crystals is one route to form hierarchical zeolites.Faujasite-type(FAU-type)zeolites are among the industrially most important zeolites and the implementation of hierarchical porosity is a promising way to optimise their catalytic and adsorptive performance.After a short general survey into routes for the preparation of hierarchical pore systems in FAU,we will review the currently existing strategies for the synthesis of FAU with layer-like morphology.Those strategies are mainly based on the presence of morphology modifying agents in the synthesis mixture.However,a very recent approach is the synthesis of layer-like FAU-type zeolite crystals assembled in an intergrown manner in the absence of such additives,just by finely adjusting the crystallization temperature.This additive-free preparation route for layer-like FAU,which appears very attractive from an ecological as well as economic point of view,is highlighted in this review.Concluding,a comparison,including powder X-ray diffraction,scanning and transmission electron microscopy,nitrogen physisorption and elemental analysis,between conventional FAU and three layer-like FAU obtained by different synthesis routes was carried out to show the structural,morphological and textural differences and similarities of these materials.展开更多
文摘The creation of intergrown layer-like zeolite crystals is one route to form hierarchical zeolites.Faujasite-type(FAU-type)zeolites are among the industrially most important zeolites and the implementation of hierarchical porosity is a promising way to optimise their catalytic and adsorptive performance.After a short general survey into routes for the preparation of hierarchical pore systems in FAU,we will review the currently existing strategies for the synthesis of FAU with layer-like morphology.Those strategies are mainly based on the presence of morphology modifying agents in the synthesis mixture.However,a very recent approach is the synthesis of layer-like FAU-type zeolite crystals assembled in an intergrown manner in the absence of such additives,just by finely adjusting the crystallization temperature.This additive-free preparation route for layer-like FAU,which appears very attractive from an ecological as well as economic point of view,is highlighted in this review.Concluding,a comparison,including powder X-ray diffraction,scanning and transmission electron microscopy,nitrogen physisorption and elemental analysis,between conventional FAU and three layer-like FAU obtained by different synthesis routes was carried out to show the structural,morphological and textural differences and similarities of these materials.
