Supported Ternary Sulfide Phases: Characterization and Catalytic Properties of Alumina-Supported Ni Ru1−S2

Mixed nickel-ruthenium sulfides supported over alumina, with different metal compositions, were prepared by stepwise impregnation and further sulfidation. The solids were characterized by XRD, XPS, HREM, STEM, and TPR, and their catalytic properties evaluated using the hydrogenation of biphenyl. XRD, XPS, TPR, and STEM measurements indicate that ternary nickel-ruthenium-sulfur compounds with a pyrite-like structure are synthesized up to an atomic ratio of Ni/(Ni + Ru) near 0.7. STEM analysis after tests shows that these phases are stable under test conditions. A 30-fold increase in hydrogenation activity is observed in comparison to pure ruthenium sulfide supported on alumina. This synergetic effect is ascribed to the existence of mixed NiRu sites with different electronic properties from those of either Ni or Ru sites by themselves.