Constructing macroscopic core@shell catalyst to boost tandem catalysis of methanol to aromatic

Two-step conversion of methanol to aromatic via olefin intermediates is an effective route to improve catalytic stability and aromatic selectivity while the current research focuses on the optimization of catalyst bed or reactor. Here, we constructed [email protected] catalyst with low Si/Al ZSM-5 as core and high Si/Al ZSM-5 as shell by a simple cladding method to achieve the tandem catalysis. By analyzing the properties and catalytic performance of the obtained catalysts, the tandem catalytic mechanism was comprehensively understood. Attributed to the appropriate coating in the macroscopic [email protected] system, the olefin generated in the shell can be diffused to the core catalyst more effectively, thus improving the coupling efficiency. Meanwhile, the pre-conversion of methanol on the shell catalyst inhibited the alkylation of generated aromatics to form polymethylbenzene and the lifetime of [email protected] was prolonged to 72.5 h. Compared with conventional dual-bed and granule-mixing, the catalytic performance over [email protected] catalyst was enhanced attributed to the close proximity and spatially and temporally ordered effect. This work firstly integrated the double ZSM-5 active center over one catalyst to catalyze the two-step reaction of methanol to aromatic, and provides the feasibility and theoretical basis for the subsequent preparation of [email protected] catalysts at the microscopic level.