Methanol conversion to aromatics (MTA) is developing due to envisioning shortage in aromatics. In this work, HZSM-5 (Si/Al=11.5) was desilicated with varying alkalinities and impregnated with 1 wt% Ga for MTA. Our most effective catalyst improved meso- and microporosities, and possessed sufficient numbers of (GaO)+-Brønsted acid sites. Improved mesoporosity accelerates inward and outward diffusions in ZSM-5 matrix: the former promotes hexahydrated Ga3+ transfer into cavities to form (GaO)+-Brønsted acid phases during impregnation, while the latter suppresses cracking by shortening residence time of yielded aromatics in ZSM-5 channels. Micropores with a narrow pore size distribution around 0.55 nm can boost aromatics selectivities, especially for o- and m-xylenes. A maximal aromatics selectivity of 60.1 % was achieved at 500 °C after moderate alkali treatment (NaOH=0.05 M) of HZSM-5. However, high aromatics output inevitably penalized catalyst durability because of higher coking rate.
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