A density functional theory study of the noble metal adsorption on the CeO₂(111) surface

Adsorption behaviors of four typical noble metals (Au, Pd, Pt, and Rh) on the CeO₂(111) surface were systematically investigated by using density functional theory method. The results indicated that Au prefers to be adsorbed on the atop site, while Pd and Pt on the O-bridge site. Rh adsorbed on the 3-fold hollow site is the most stable configurations. When the noble metals are adsorbed on the atop site, the adsorption strength is in the order of Pt > Rh > Pd > Au. New electronic peaks are present between the Ce 4f and O 2p peaks when Pd, Pt, and Rh atoms are adsorbed on the CeO₂(111) surface, while no peak is found for the adsorption of Au; the d electronic peak of Au overlaps with the O 2p peaks at-4 to-1 eV. According to the density of states (DOS) analysis, when Au is adsorbed on the atop site, Pd and Pt on the bridge site, and Rh on the 3-fold hollow site, their interactions with surface oxygen atoms on the CeO₂(111) surface are stronger than other configurations, which is in good agreement with the results of Bader charge population.