Dehydrogenation of Methylcyclohexane over Zinc-containing Platinum/Alumina Catalysts

The catalytic performance of Pt supported on Al2O3, TiO2, SiO2 and activated carbon (AC) was investigated for the dehydrogenation of methylcyclohexane (MCH). The additive effects of Ce, Ga, Mn, Sn, and Zn on the Pt catalysts were also studied. Pt was highly dispersed on Al2O3 as an effective support, and was active for the dehydrogenation reaction. Sequential impregnation of Zn and Pt into Al2O3 in this order resulted in greatly increased MCH dehydrogenation activity and decreased methane selectivity, which were dependent on the amount of the loaded Zn. FT-IR of adsorbed CO, TEM, and XRD measurements revealed that dispersion of Pt on Al2O3 was little changed by loading Zn, and electron donation from Zn to Pt occurred. Therefore, the high dispersion and electron-donating ability of Pt in Zn–Pt/Al2O3 are responsible for the excellent catalytic performance. In contrast, addition of Zn to AC-supported Pt catalyst reduced the catalytic activity probably due to the formation of aggregated PtZn alloy particles on the support.