Stabilization of atomically dispersed rhodium sites on ceria-based supports under reaction conditions probed by in situ infrared spectroscopy

In this work, atomically dispersed rhodium over co-precipitated ceria-based supports were prepared by wet impregnation. The structural and surface properties of materials were investigated by X-ray diffraction, N2 physisorption isotherms, and X-ray photoelectron spectroscopy. The fraction of isolated sites was quantified by infrared spectroscopy using CO as a probe molecule. The formation of a defective surface by incorporation of 15% (mol/mol) of zirconium on ceria structure increased ~5-fold the fraction of isolated sites on catalyst compared to unmodified ceria. The doped-support efficiently trapped rhodium atoms avoiding agglomeration and increasing stability during CO oxidation reaction in a wide range of temperatures (30–200 °C) when compared to single-sites deposited on silica.