Low-Temperature Hydrogenation and Dehydrogenation of 1,3-Cyclohexadiene on Pt/Ni Bimetallic Catalysts

Pt-Ni bimetallic catalysts and their corresponding monometallic catalysts supported on γ-Al2O3 were prepared by incipient wetness impregnation and characterized by CO chemisorption. Their low-temperature activity for the hydrogenation and dehydrogenation of 1,3-cyclohexadiene (1,3-CHD) was tested at 308 K in a batch reactor using Fourier transform infrared spectroscopy. The Pt-Ni/γ-Al2O3 bimetallic catalyst showed higher activity than either Pt/γ-Al2O3 or Ni/γ-Al2O3. We correlated the experimental results with density functional theory calculations of the binding energy for 1,3-CHD on the corresponding model surfaces. The correlation confirmed that bimetallic surfaces with weaker cycloalkene binding energies generally showed higher hydrogenation activity.