Effect of platinum on the hydrogenation activity of nickel catalysts

Ni, Pt and Ni-Pt supported on SiO2 and TiO2-SiO2 catalysts containing about 5 wt.% of the active phase were characterised using BET, ICP, TPR, XRD and TOF-SIMS methods and tested in the reaction of toluene hydrogenation to methylcyclohexane. XRD and TOF-SIMS results show that nickel oxide is better dispersed on the binary support than on SiO2. TPR indicates that platinum promotes the reducibility of supported NiO. Transformations of metallic phase in the successive TPR–TPO cycles have been discussed. Catalysts supported on binary support show considerably higher catalytic activity in the reaction of toluene hydrogenation than those supported on silica. The bimetallic catalysts containing ca. 0.5 wt.% Pt are more active than related monometallic platinum catalysts, containing comparable amount of platinum.