Methanol Conversion to Aromatics over Ga–supported HZSM‐5 with Evolved Meso‐ and Microporosities by Desilication

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 Ga 3+ 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.