Intra-Crystalline Mesoporous Zeolite [Al,Zr]‑Y for Catalytic Cracking

A facile, direct, and template-free synthesis of intracrystalline mesoporous zeolite Y involving the introduction of Zr atoms under hydrothermal conditions is proposed for the first time. The presence of mesopores in the product was confirmed by N₂ adsorption–desorption isotherms and transmission electron microscopy, while the results of UV–vis diffuse reflectance spectroscopy, X-ray photoelectron spectroscopy, ²⁹Si MAS NMR spectroscopy, and Fourier-transform infrared spectroscopy analyses confirmed that Zr atoms were successfully introduced to the zeolite framework. The density functional theory was used hypothesize the origin of the mesopores. Compared with conventional USY (ultrastable Y) zeolite, [Al,Zr]-USY zeolite has an excellent mesoporous structure because of the framework mesoporous defects of [Al,Zr]-NaY. A catalytic study performed using the cracking of 1,3,5-triisopropylbenzene as a model application revealed that the [Al,Zr]-USY zeolite exhibits superior activity to that of typical USY zeolite. Thus, this synthetic method provides a convenient and environmentally benign strategy for the synthesis of hierarchical zeolites, particularly for use in the fluid catalytic cracking industry, in which zeolites are routinely applied as cracking catalysts.