Bridging the materials gap between single crystal and supported catalysts using polycrystalline Ni/Pt bimetallic surfaces for cyclohexene hydrogenation

The current work utilizes the adsorption of hydrogen and the hydrogenation of cyclohexene as probe reactions to bridge the materials gap between single crystal and polycrystalline Ni/Pt bimetallic surfaces. Previous studies on Ni-modified Pt(1 1 1) have identified the formation of a Pt–Ni–Pt(1 1 1) subsurface structure that binds atomic hydrogen and cyclohexene more weakly, leading to a low-temperature hydrogenation pathway not present on either of the parent metal surfaces. In the current work, the Pt–Ni–Pt subsurface structure is prepared by depositing Ni on a polycrystalline Pt foil substrate. The adsorption of hydrogen and hydrogenation of cyclohexene are investigated using surface science experiments and density functional theory (DFT) calculations. The polycrystalline Pt–Ni–Pt subsurface structure shows general similarities to Pt–Ni–Pt(1 1 1) in the low-temperature hydrogenation pathway, demonstrating the validity of using single crystals to predict activity trends for more complex surfaces.