Catalytic oxidation with H2O2 is a promising method for NOx emission control in coal-fired power plants. Hematite-based catalysts are attracting increased attention because of their surface redox reactivity. To elucidate the NO oxidation mechanism on alpha-Fe2O3 surfaces, density functional theory (DFT) calculations were conducted by investigating the adsorption characteristics of nitric oxide (NO) and hydrogen peroxide (H2O2) on perfect and oxygen defect alpha-Fe2O3 (001) surfaces. Results show that NO was molecularly adsorbed on two kinds of surfaces. H2O2 adsorption on perfect surface was also in a molecular form; however, H2O2 dissociation occurred on oxygen defect alpha-Fe2O3 (001) surface. The adsorption intensities of the two gas molecules in perfect alpha-Fe2O3 (001) surface followed the order NO > H2O2, and the opposite was true for the oxygen defect alpha-Fe2O3 (001). Oxygen vacancy remarkably enhanced the adsorption intensities of NO and H2O2 and promoted H2O2 decomposition on catalyst surface. As an oxidative product of NO, H2O2 was synthesized when NO and H2O2 co-adsorbed on the oxygen defect alpha-Fe2O3 (001) surface. Analyses of Mulliken population, electron density difference, and partial density of states showed that H2O2 decomposition followed the Haber-Weiss mechanism. The trends of equilibrium constants suggested that NO adsorption on alpha-Fe2O3 (001) surface was more favorable at low than at high temperatures, whereas H2O2 adsorption was favorable between 375 and 450 K. These calculations results well agreed with the experimental ones and further elucidates the reaction mechanisms. (C) 2017 Elsevier B.V. All rights reserved.