CO Adsorption on Monometallic and Bimetallic Au-Pd Nanoparticles Supported on Oxide Thin Films

Supported Au-Pd catalysts have been shown to exhibit superior catalytic pet-fern-lances when compared to their monometallic counterparts in a variety of reactions. In addition. the nature of the support often plays a critical role in reactivity. To gain a deeper understanding of the structure reactivity relationship of the catalysts, here we have employed model systems where monometallic and bimetallic Au-Pd nanoparticles are deposited on well-ordered thin films of reducible and oxides (i.e., Fe3O3(111), MgO(100), and CeO2(111)). Surface structures or the model systems were characterized by temperature-programmed desorption, sum frequency generation, and infrared reflection absorption spectroscopy of as a probe molecule. In agreement with previous studies, the results show segregation of gold to the surface. Density functional theory calculations confirm that Au prefers to be at the edges of AuPd alloy particles under vacuum conditions. Strong similarities between the spectral features observed for metal particles on these oxide substrates suggest that the reducibility of the support does not affect the surface structure.