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

[Display omitted] •Macroscopic core@shell catalyst was prepared for two-step MTA conversion.•Controlling coat degree promoted the utilization efficiency of olefin intermediate.•Pre-conversion of methanol in shell catalyst weakened alkylation of formed aromatic.•High catalytic stability and aromatic selectivity were achieved for MTA reaction. 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 core@shell 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 core@shell 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 NK60@Z440 was prolonged to 72.5 h. Compared with conventional dual-bed and granule-mixing, the catalytic performance over core@shell 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 core@shell catalysts at the microscopic level.