Characterization and catalytic activity of Ni-SY/SiO2-Al2O3 hydrocracking catalysts

Characterization of Ni-W SiO2-Al2O3 catalysts was carried out by microcalor imetry, TPR and oxygen chemisorption. The effect of incorporation of indivi dual metals and their sequence of addition to the support on the properties and catalytic activity for cyclohexene hydrogenation and cumene cracking w as investigated While the addition of nickel to SiO2-Al2O3 has little effec t on the acidity, tungsten has generated some new strong acid sites, which do not seem to have beneficial effect for cumene cracking. Low temperature TPR peak in the bimetallic catalysts falls around 760 K due to NI-W species while the high temperature peak around 1115-1223K; corresponds to W specie s;. W/SiO2-Al2O3 has a lower oxygen chemisorption than its nickel counterpa rt but has a higher hydrogenation rate. Tungsten is the active metal for hy drogenation. W-Ni/SiO2-Al2O3 catalyst has better hydrogenation and cracking activity.