Interfacial properties of NM/CeO2(111) (NM = noble metal atoms or clusters of Pd, Pt and Rh): a first principles study

Abstract

Results from first principles calculations present a rather clear atomic and electronic levelpicture of the interaction of single noble metals (NM: Pd, Pt and Rh) and the correspondingNM4 clusterswith a CeO2(111) surface. The most preferable adsorption sites for both the Pd and Pt adatomsare the surface O-bridge sites, while the Rh adatom prefers to stay at theO-hollow site. The Rh adatom shows much stronger interaction with theCeO2(111) surface than the Pd and Pt adatoms do, while the Pd adatom has the smallest adsorptionenergy. The dependence of the Rh/ceria interfacial properties on the value of the HubbardU-term was tested systematically.The small clusters show stronger interaction than the corresponding single NM adatoms on theCeO2(111) surface. The reaction of was found for both the single NM adatoms and the small cluster adsorbate, indicating that NMadsorbates were mainly oxidized by the surface Ce ions with obvious charge transfer from NM to theCeO2(111) surface. The three base atoms of the small clusters that bonded with theCeO2(111) surface showed positive charges, while the top metal atoms of theNM4 clusters had a small negative charge.