Transformation of metal species and catalytic reaction mechanism of metal modified ZSM-5 in alkane aromatization

Light aromatics, important organic intermediates, are mainly produced by naphtha reforming technology. However, recent attention has been focused on the development of processes that directly convert C1-C6 to light aromatics due to the economics of C1-C6 as a raw material. ZSM-5 is a potential catalyst for its excellent aromatization activity. The complexity of the internal chemical environment of ZSM-5 and the different interpretations of experimental results lead to the lack of a unified understanding of the molecular level details of the active sites and the reaction mechanism before and during the reaction. Therefore, in this paper, firstly, the widely studied Mo, Ga and Zn supported ZSM-5 were selected and the relationship between the anchoring sites or molecular structure of the metal and the catalyst activity in the preparation and reaction period was reviewed. Secondly, the activity and stability of Ga, Zn, Fe and B isomorphous substituted ZSM-5 were introduced. Finally, the controversy of monofunctional and bifunctional mechanism of ZSM-5 in alkane aromatization was discussed. This paper also provides suggestions for future research to fill the information gap found in the current literature.