Aromatization of C_5 hydrocarbons over Ga-modified hierarchical HZSM-5 nanosheets

摘要

The aromatization of C-5 hydrocarbons is an interesting process to convert low-cost petrochemical-based compounds to high value-added compounds, especially benzene, toluene, ethylbenzene, and xylene (BTEX). However, the development of an appropriate catalyst for this reaction is still challenging both academic and industrial points of view. In this context, the Ga-incorporated zeolites with hierarchical nanosheet structures have been successfully prepared by various preparation methods, including an in-situ approach, an ion-exchange, and impregnation methods. Compared to the conventional catalyst, Ga-modified HZSM-5 nanosheets exhibited the significantly improved catalytic performance with n-pentane conversion and BTEX selectivity of over 40% and 45%, respectively. From the structural analysis of the roles of Ga active species in the C-5 aromatization, it is also important to mention that the enhanced catalytic activity related to an increase in the contribution degree of highly dispersed tetrahedral Ga species attached to the zeolite framework compared to bulk Ga2O3 particles in nanosheet structures, which was confirmed by both experimental and theoretical (DFT calculation) data. This work opens up new perspectives for the ZSM-5 nanosheet catalyst design in the application of the C-5 aromatization.