Catalytic conversion of light alkanes to aromatics by metal-containing HZSM-5 zeolite catalysts-A review

The directly catalytic conversion of C-2-C-6 alkanes to aromatics has aroused widespread interest from both academia and industry because of the growing demand for aromatics. Compared with pure HZSM-5 zeolites, the addition of metal species is required to enhance the selectivity of BTX by inhibiting undesirable side reactions. This paper reviewed the research progress of aromatization for light alkanes on HZSM-5 zeolites and its metal-containing catalysts based on theoretical and experimental research. The chemical states of metal species and dehydrogenation mechanisms of Zn and Ga-containing HZSM-5 catalysts are introduced in detail. The interaction of Zn or Ga with HZSM-5 zeolite produces Zn or Ga-Lewis acid sites that can promote the dehydrogenation of alkanes and intermediate products, thereby increasing the selectivity of BTX. On Zn-containing HZSM-5, only the Zn species were found to be involved in the dehydrogenation activation process of alkanes. In contrast, on Ga-containing HZSM-5, the acid-base pairs composed of Ga species with adjacent basic oxygen ions are responsible for the dehydrogenation of alkanes. However, there is still controversy over the active species of alkanes dehydrogenation, which needs further investigation.

Automated summary

This paper reviews the research progress of aromatization for light alkanes on HZSM-5 zeolites and its metal-containing catalysts, focusing on the introduction of metal species and dehydrogenation mechanisms to enhance the selectivity of BTX. The interaction of Zn or Ga with HZSM-5 zeolite forms Lewis acid sites, promoting the dehydrogenation of alkanes and intermediate products to increase BTX selectivity.