Structural changes in H-ZSM-5 zeolite induced by selective framework dissolution and their consequences for the catalytic performance in the methanol-to-hydrocarbons reaction

• H-ZSM-5 was subjected to a partial framework dissolution by NaOH etching. • At optimized etching conditions mesopores were formed without loss of crystallinity. • The generation of mesopores leads to a shift of selectivity in the MTH reaction to towards a higher amount of BTX aromatics • Structural changes induced by partial framework dissolution lead to a higher stability of H-ZSM-5 in the MTH reaction. Traditionally inexpensive alternatives, such as etching and chemical reductions, offer efficient possibilities for creating dual porosity, reorganizing zeolitic phases, and enhancing the accessibility of active species that facilitate hydrocarbon conversions and industrial scale-up. Through a systematic approach, framework dissolution (FD) of an MFI zeolite was investigated to assess its structural characteristics and catalytic performance. N 2 sorption, XRD, solid-state NMR, thermogravimetry, and electron microscopy techniques were employed to examine the impact of FD on the morphological changes. The results suggest that the FD process can selectively create ordered mesoporous systems. However, the total acidities decrease with increasing NaOH concentration. The broad distribution of hydrocarbon (HC) products from the autocatalysis of single-pass methanol showed that BTX accounted for 57 % of the average yield in an aromatic-rich HC base. Meanwhile, C 2 –C 4 HCs averaged 15 % over the mesoporous zeolites, significantly favouring a low aromatics-to-olefins selectivity ratio. The variety of products, including p-xylene and olefin selectivity, suggests that controlled FD can extend the zeolite lifespan and regulate hydrogen transfers and cyclization products during C–C bond coupling, by influencing shape-to-pore interconnectivity.