Effect of metal–support interaction on the catalytic performance of Ni/Al2O3 for selective hydrogenation of isoprene

The effect of the interaction between metal and support on the performance of different phases alumina supported nickel catalysts was demonstrated in liquid phase selective hydrogenation of isoprene in simulated gasoline. Catalysts supported on γ-Al2O3 and κ-Al2O3 were characterized by BET, XRD, TPR, and XPS techniques. The results showed that a “surface spinel”, NiAl2O4 was formed. The supported nickel ions preferentially incorporate into the tetrahedral vacancies of γ-Al2O3 support to form SMSI (strong metal–support interaction), while WMSI (weak metal–support interaction) was formed on κ-Al2O3 support with little tetrahedral vacancy. When there were enough hydrogenation sites, the Ni/γ-Al2O3 catalysts with SMSI which can resist carbon deposition, performed higher isoprene conversion, higher stability and lower selectivity than the same nickel loading Ni/κ-Al2O3 samples with WMSI. The weak interaction had a positive effect on the formation of coke, which was mainly related to the hydrogenolytic sites, leading to main reaction with high mono-olefins selectivity with isoprene conversion decrease evidently.

Comparable studies of metal–support interaction with γ-Al2O3 and κ-Al2O3 phases effects on catalytic performance of Ni/Al2O3 for selective hydrogenation of isoprene have been carried out in simulated gasoline. The degree of the interaction connected with the nickel content and alumina phase affects coke deposition and hydrogenation sites deactivation significantly, leading to the difference of the selectivity of mono-olefins in selective hydrogenation.Figure optionsDownload high-quality image (85 K)Download as PowerPoint slideHighlights
► The different metal–support interactions over two alumina supports were characterized.
► The effect of the different interaction on catalytic performance was explained.
► The weak interaction resisting coke deposition was related to the hydrogenolytic sites.