Understanding the SMSI effect through the use of model catalysts

Abstract

Metallic nanoparticles are widely used in several catalytic reactions. The catalytic properties are strongly dependents on the surface structure of the nanoparticles. The strong metal support interaction (SMSI) effect is known to modify significantly the surface of nanoparticle supported on reducible supports. This influence can be considered positive or negative on the final catalytic properties depending on the system studied. Although the SMSI effect has been discovered more than 30 years ago, there is not yet a clear understanding about the mechanism of the SMSI effect for the case of metallic nanoparticles supported on ceria (CeO2). The use of model catalysts enables to simulate the dependence of extremely complex parameters of a real catalyst (used in the practice). In this project, a ceria film will be grown epitaxially on a Rh(111) single crystal substrate. After that, Pd and Au will be deposited separately onto the surface of the CeO2/Rh(111) sample in order to produce supported metallic nanoparticles. Therewith, it will be possible to simulate the existence of the SMSI effect and to understand the mechanism that modifies the catalytic properties of the nanoparticles. The model catalyst will be studied by using the X-ray Photoelectron Diffraction (XPD), X-ray Photoelectron Spectroscopy (XPS), Scanning Tunneling Microscopy (STM) and Low Energy Electron Diffraction (LEED) techniques. In this way, it will be possible to perform important contributions for the projection of future catalysts used in the industry.