NO adsorption and transformation on the BaO surfaces from density functional theory calculations

Abstract

Density functional theory combined with embedded cluster model calculations have been used to investigate the NO adsorption and transformation reactions on the BaO (100) surfaces. NO is found to adsorb on the anion sites to form a NO2 2 – species, which can then couple with another NO to form a N2 O3 2− species. These surface species provide an alternative explanation for the infrared bands that were used to be assigned to the nitrite/ nitrate and hyponitrite species. The calculations suggest a large intrinsic barrier for the transformation from N2 O3 2− to N2 O2 2−. The latter species acts as a chemisorbed N 2 O, which is envisioned as a key intermediate for further NO reduction. The present study provides a detailed description at the molecular level for the NO/ BaO (100) system, which shed some light on the NO x storage – reduction systems, as well as NO direct decomposition.