Na, Mg, and Ca as promoters for N2O adsorption on char surface: A theoretical study

• The effect of Na, Mg and Ca addition on N 2 O adsorption on char was studied by DFT. • The pristine zigzag char models with and without lactone group was selected. • The metal incorporation increases the energy released during the adsorption of N 2 O. • The metal incorporation significantly facilitated the adsorption of N 2 O on char. This study aims to evaluate the impact of Na, Mg and Ca on the adsorption of N 2 O by char based on density-functional theory (DFT) at M06-2X/6-311G(d) level using pristine zigzag (PZ) char models with and without lactone group. The adsorption energy, the highest occupied molecular orbital (HOMO)-lowest unoccupied molecular orbital (LUMO) energy gap, electrostatic potential (ESP), electron density difference (EDD), atomic dipole moment corrected hirshfeld (ADCH) charge, and the weak intermolecular interactions were analyzed. Results show that the metal incorporation has little effect on the carbonaceous structure but significantly promotes the adsorption of N 2 O on char. Further investigations suggest that the metal incorporation induces more valence electrons, and enhances the electron transfer between the metals and carbon surface, thus facilitating char activity to adsorb N 2 O. Overall, this study provides new insights into the mechanisms of N 2 O adsorption by heteroatom-incorporation char.