To clarify the heterogeneous reduction reaction mechanisms,NO chemisorptions on several char models with different configurations were investigated using density functional theory in this paper.Char models and NO adsorption products were optimized at B3LYP /6-31G(d) level.The results show that NO chemisorption on the surface of pure carbon is exothermic.NO chemisorptions on nitrogen-containing char with the formation of N—N bond are exothermic processes.It is exothermic when N—O bond is formed with NO chemi...