Microwave-Assisted Hydrogen Production from Methylcyclohexane Dehydrogenation over Pt–Sn/Al ₂ O ₃ Catalysts: Investigation on the Effect of Sn Promoter

Catalytic dehydrogenation of a liquid organic hydrogen carrier like methylcyclohexane is considered as a potential solution for hydrogen transportation storage. Hydrogen production via the catalytic dehydrogenation of methylcyclohexane (MCH) was performed over a Pt-based catalyst in a microwave reactor to determine the effective catalyst systems. It was found that Pt/Al₂O₃ displayed good MCH conversion and hydrogen production rates but faced urgent issues including C-C bond cleavage side reactions and undesirable coke deposition. After Sn was introduced as a promoter, we explored the optimal ratio of Sn and its promoter effects. Pt_0.6Sn_0.6/Al₂O₃ showed comparable dehydrogenation activity and less coke compared with single Pt/Al₂O₃. According to the characterization analysis of XPS, H₂-TPR and NH₃-TPD, the Sn promoter induced the formation of the Pt-Sn alloy and masked the medium and strong acidic site of Al₂O₃. Excessive Sn loading enhanced the formation of Sn rich alloy, which explains the reduced catalytic activity and stability.