Conversion of Methanol to Light Aromatics on Zn-Modified Nano-HZSM-5 Zeolite Catalysts

A series of Zn-modified nano-HZSM-5 (Zn/NZ) zeolite catalysts were prepared and used in the conversion of methanol to light aromatics (benzene, toluene, and xylene; BTX). The reaction conditions and loading of Zn exhibited a significant influence on the BTX yield. The interaction of Zn species with hydroxyl groups (OH) occurred on the HZSM-5 surface with the loading of Zn on a HZSM-5 zeolite. Such interaction distinctly changed the texture and acidity of the Zn/HZSM-5 catalyst. On the other hand, reduction of the Zn/NZ crystal size not only improved the interaction of Zn species with HZSM-5 but also enhanced the resistance of coke deposition. The high BTX yield of 67.7% and good catalytic stability were obtained on a 0.5 wt% Zn/NZ catalyst, mainly because of its proper concentration and distribution of acide sites as well as the small crystal size with improved physical transport.