DFT insights into the reaction and coupling mechanisms of H2 and CO with FeO in hydrogen-based shaft furnace

The hydrogen-based shaft furnace (HSF) represents a promising route toward cleaner production in iron and steel industry. In this work, the reaction mechanism of H 2 and CO with FeO was systematically explored using density functional theory (DFT). The adsorption energies of H 2 and CO on the pure FeO(100) surface are −0.82 eV and −0.88 eV, respectively, and indicating a competitive adsorption relationship. H 2 adsorption weakens while CO adsorption is enhanced on reduced surfaces, and leading to a synergistic effect. The energy barriers for the surface reactions of H 2 and CO are found to be 2.33 eV and 2.57 eV, respectively, with H 2 exhibiting the lower barrier. Meanwhile, the energy barriers associated with the migration of O atom increase progressively to 1.43, 1.65, and 2.94 eV as the reduction advances. Temperature elevation is also shown to accelerate both the reaction kinetics of H 2 /CO and the migration rates of O atom. In the initial stage, the reduction rate is governed by surface reactions, whereas in later stage, it becomes limited by O migration for H 2 , and by both processes for CO. Although higher temperatures negatively affect adsorption, those thermodynamically favor reduction reactions and mitigate the disadvantage associated with H 2 reaction. Enhancing the H 2 ratio and increasing temperature are critical for improving HSF reduction efficiency. Moreover, maintaining a small amount of CO can promote H 2 adsorption in later stage. This work provides theoretical guidance for achieving high-efficiency and low-emission ironmaking using HSF technology. • H 2 and CO show competitive adsorption on pure and synergistic on reduced FeO. • H 2 exhibits lower reaction energy barrier than CO on FeO surface. • Energy barriers for O migration rise progressively during reduction. • In the later stage, H 2 is limited by O migration; CO shows mixed control. • Elevated temperature improves both reaction kinetics and thermodynamics.