Interaction of Pd single atoms with different CeO2 crystal planes: a first-principles study

Abstract The adsorption of single Pd atoms on the various CeO 2 surfaces, including (111), (110), and (100), has been studied based on the first-principles calculations. It is found that, according to the calculated adsorption energy, interaction strength between Pd and the three CeO 2 surfaces follows the order of (100) > (110) > (111). Interestingly, the effect of the electron localization on the surface Ce ions due to the Pd adsorption on its adsorption stability is more significant for the (110) surface than that for the (111) and (100) surfaces. We also find that the formal oxidation states of Pd 0 , Pd δ+ (δ  1+ may appear on the CeO 2 (111) surface, and Pd δ+ (δ  1+ could coexist on the CeO 2 (100) surfaces. However, under suitable conditions the CeO 2 (110) surface may be covered with Pd 2+ ions. Present theoretical results clearly suggest that the interaction between Pd and CeO 2 nanocrystals significantly depends on the crystal planes of CeO 2 . It is expected that our study will give useful insights into the effect of CeO 2 crystal plane on the physicochemical and catalytic properties of CeO 2 supported Pd catalyst.