Analysis of the Reaction of Carbon with NO/N2O Using Ab Initio Molecular Orbital Theory

An attempt was made to analyze the reaction of carbon with NO or N 2 O by using an ab initio molecular orbital theory. This method allows the simulation of the chemisorption process of these gas molecules on zigzag and armchair edge sites of carbon. It was found that NO adsorption with the N atom down is more thermally favorable than the adsorption with the O atom down, while the O down mode is more favorable than the N down one for N 2 O adsorption because the former process releases a stable N 2 molecule to form a surface oxygen complex. The chemisorption of NO or N 2 O with its bond axis parallel to the edge line gave the most stable chemisorbed species. The presence of surface oxygen complexes (quinone-type carbonyl group) on the edge decreases the strength of some bonds in NO- and N 2 O-chemisorbed species and consequently lowers their thermal stability. Furthermore, the N 2 formation process in the C−NO/N 2 O reaction was analyzed and possible N 2 formation routes were proposed. The routes predicted by the molecular orbital theory were compared with the previous experimental results.