First Principles Study of CO Adsorption on Atomic Pd Supported on Metal Oxide Surfaces (ZrO2(110), MgO(100), CeO2(110))

We have performed density functional theory (DFT) quantum periodic calculations to investigate the interaction between atomic Pd and oxide surfaces of ZrO2(110), MgO(100), and CeO2(110). In this calculation, Pd adsorption energy on the surface oxygen atom sites of those oxide surfaces correlated with the position of the d electron density center of Pd atom except for on the surface metal atom site. Furthermore, CO adsorption on Pd atoms adsorbed on the surface of those three kinds of oxide surfaces was investigated. The CO adsorption energy did not correlate with the position of d electron density center of Pd at the adsorption sites when they are summarized on each oxide surface but correlated with it when three kinds of oxide surface are grouped by adsorption site. Since Pd atom is the smallest size, it is easily influenced by oxide surface atoms and adsorbates. These results suggest that the nature of Pd atom adsorbed on oxide surface changes depending on where Pd atoms adsorb on the oxide surface, and is controlled by d electron density center.