Microwave-Assisted Hydrogen Production from Methylcyclohexane Dehydrogenation over Pt–Sn/Al₂O₃ 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. Pt0.6Sn0.6/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.