Hydrogenation of benzene to cyclohexene on an unsupported ruthenium catalyst: an esca study of titanium poisoned catalysts

ESCA data show that the addition of titanium to a ruthenium catalyst gives a catalyst containing some metallic ruthenium and a mixed titanium-ruthenium hydrous oxide. The ratio of ruthenium in the metallic form to ruthenium in the hydrous oxide form decreases with increasing titanium concentration. The poisoning effect of titanium on the hydrogenation activity results from the reduced amount of ruthenium metal available.