Simulating the Complexities of Heterogeneous Catalysis with Model Systems: Case studies of SiO₂ Supported Pt-Group Metals

Model catalyst surfaces, consisting of vapor-deposited metal nanoparticles supported on a planar oxide support, can help to link reactivity studies on well-defined single crystal surfaces with those conducted on high-surface area supported catalysts. When coupled with near atmospheric pressure kinetic and spectroscopic techniques, these well-defined model catalyst surfaces represent a useful approach to combine the power of surface analytical techniques with reactivity studies under relevant reaction conditions. Here, we review recent results of our investigations characterizing the physical and catalytic properties of Pt/SiO₂ and Rh/SiO₂ model catalyst surfaces. As will be discussed, the model catalyst approach can help simulate the complexities of catalytic reactions on supported catalysts, helping to provide insights into the role of particle size, particle morphology, and surface adsorbates in dictating the observed structure-sensitivity (activity and selectivity) during reactions at near atmospheric pressures.