Interaction between NO and Na, O, S, Cl on Au and Pd(111) surfaces.

NO co-adsorption with X (X = Na, O, S, and Cl) on Au and Pd(111) surfaces is studied using density functional theory (DFT) calculations to get a deeper insight into the extraordinary sulfur enhanced adsorption on the Au surface. It is found that both electronegative and electropositive adatoms can enhance NO adsorption on Au(111). In Na + NO/Au(111), the strong electrostatic attraction between Na and NO dominates and stabilizes NO adsorption, though Na-induced surface negative charging weakens NO adsorption. In (O, S, Cl) + NO/Au, the electronegative atoms would induce a slight surface distortion and enhance NO adsorption accordingly. NO adsorption on Pd(111) is enhanced by Na, but weakened by electronegative species. We suggest that the unique features of noble metals, i.e., the narrow DOS at the Fermi level (E(F)) and the deep buried d-band center, should play an important role in the promotion of NO adsorption on their surface as the CO case.