Post‐Synthetic Ensembling Design of Hierarchically Ordered FAU‐type Zeolite Frameworks for Vacuum Gas Oil Hydrocracking

Abstract

Zeolites hold importance as catalysts and membranes across numerous industrial processes that produce most of the world’s fuels and chemicals. In zeolite catalysis, the rate of molecular diffusion inside the micropore channels defines the catalyst longevity and selectivity, thereby influencing the catalytic process efficiency. Decreasing the diffusion pathlengths of zeolites to the nanoscopic level by fabricating well‐organized nanoporous architecture can efficiently overcome their intrinsic mass‐transfer limitations without losing hydrothermal stability. We report a rational post‐synthetic design for the synthesis of hierarchically ordered FAU‐type zeolites exhibiting 2D‐hexagonal (P6mm) and 3D‐cubic (Ia[[EQUATION]]d) mesopore channels formed by a post‐synthetic approach. The synthesis involves methodical incision of the parent zeolite into unit‐cell level zeolitic fragments by in situ generated base and bulky surfactants. The micellar ensembles formed by these surfactant‐zeolite interactions are subsequently reorganized into various ordered mesophases by tuning the micellar curvature with ion‐specific interactions (Hofmeister effect). Unlike conventional crystallization, which offers poor control over mesophase formation due to kinetic constraints, here, crystalline mesostructures can be developed under dilute, mild alkaline conditions by controlled reassembly. The prepared hierarchically ordered zeolites with nanometric diffusion pathlengths have demonstrated excellent yields of naphtha and middle‐distillates in low‐pressure vacuum gas oil hydrocracking with decreased coke deposition.