Conversion of Light Alkane to Value-Added Chemicals over ZSM-5/Metal Promoted Catalysts

Gallium–platinum promoted HZSM-5 is found to be a promising catalyst for ethane aromatization reaction. The influence of Pt as a promoter on the activity of Ga/HZSM-5 catalyst for ethane aromatization has been investigated. Comparative study was performed between bimetallic Ga–Pt based and Mo based HZSM-5, where the GaPt/HZSM-5 showed better aromatic and hydrogen selectivity. Pt promoted Ga/HZSM-5 catalyst exhibited higher activity compared to pure Ga/HZSM-5 catalyst. The presence of platinum in the gallium zeolite considerably accelerated dehydrogenation step in ethane aromatization. In addition, GaPt/HSZM-5 deactivated significantly slower than Mo/HZSM-5 and Ga/HZSM-5. TPO study of spent catalysts revealed that carbonaceous deposit on GaPt/HZSM-5 catalyst was burnt off at lower temperature compared to pure Ga/HZSM-5 catalyst, indicating the presence of Pt facilitated hydrogen spillover resulting in hydrogenolysis of coke precursors. The reaction mechanism associated with aromatic formation is postulated based on the correlation between catalytic performance and surface characterization.