Methanol-assisted NO oxidation under an oxygen atmosphere for efficient denitration: Experiments and ReaxFF-MD simulations

[Display omitted] •A catalyst-free denitration process using methanol and oxygen was developed.•The maximum NO removal efficiency reached 94.6 %, with 55.1 % of NO converted to NO2.•The evolution of hydrogen is tracked through the atomic labeling method.•The generation pathways of oxidative intermediates were proposed.•The specific contributions of OH, HO2, and H2O2 to NO oxidation were elucidated. The development of selective catalytic reduction technologies for controlling nitrogen oxides (NOx) emissions in flue gas is hampered by high equipment and catalyst costs. In this study, a catalyst-free and efficient denitration process using methanol and oxygen as reactants was developed. Various gas atmospheres with differing concentrations were investigated to remove NO without catalysts. The addition of methanol significantly enhanced NO removal efficiency, reaching 94.6 % at 550 °C, with 55.1 % of NO converted to NO2, which can be absorbed by downstream alkali solutions. Reactive force field molecular dynamics (ReaxFF-MD) simulations were employed to analyze the atomic level NO oxidation mechanism in the CH3OH/NO/O2/H2O homogeneous reaction system. The simulation revealed the generation pathway of three key oxidizing intermediates (OH, HO2, and H2O2) and their roles in NO oxidation. This study offers critical insights into developing a cost-effective denitration process, highlighting the potential for improved NOx emission control.