Hydro-dehydrogenation of six-member hydrocarbon cycles on supported platinum–cobalt bimetallic catalysts Original Research Article

The dehydrogenation of cyclohexane and hydrogenation of benzene and toluene were studied on alumina- and NaY-supported Pt, Co and Pt–Co catalysts. The toluene/benzene adsorption equilibrium constant ratios were also determined. Hydro-dehydrogenation data were compared with the activities of these catalysts in CO conversion and methane 1H–2H exchange data determined and published earlier for the same catalysts. Addition of Co to Pt reduced the hydro-dehydrogenation conversion rates. This effect was substantially stronger for benzene and toluene hydrogenation than that for dehydrogenation of cyclohexane. The turnover frequency (TOF) value for cyclohexane dehydrogenation indicated a synergy effect between Pt and Co in case of alumina supported Pt:Co sample of 50:50 at%. The TOF values indicated also the existence of significant “cooperation” between Pt and Co in PtCo/Al2O3 catalysts. Synergy, found for all samples in formation of oxygenates from CO is elucidated on the basis of Pt–Co interaction, indicated by the increased toluene/benzene adsorption equilibrium constant ratio on alumina supported PtCo catalysts. A positive correlation was observed between adsorption equilibrium constants and conversion rates of the different hydrocarbons.