Regensburg 2025 – scientific programme

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MM: Fachverband Metall- und Materialphysik

MM 7: Materials for the Storage and Conversion of Energy

MM 7.3: Talk

Monday, March 17, 2025, 16:15–16:30, H22

Hydrogen-based reduction of iron oxide surfaces studied by ab-initio calculations — •Ahmed Abdelkawy, Mira Todorova, and Jörg Neugebauer — Max Planck Institute for Sustainable Materials, Max-Planck-Str.1, 40470 Düsseldorf

The production of pure iron from the iron oxide ores is a very energy-intensive process. Additionally, the dependency on carbon and carbon monoxide as reducing agents results in CO2 as an intrinsic byproduct of the reaction. Consequently, the steel industry is responsible for more than 6% of the global CO2 emissions. Using Hydrogen (H) as a reducing agent would result in water being released instead. Two important aspects in this context are (i) the relative thermodynamics stability of iron oxide facets under different conditions, as this will determine their abundance and (ii) the interaction of H with the oxide surfaces, as these will catalyse the reaction. This work, which is an initial step toward understanding the complex process of the H-based reduction of iron oxides, focuses on Hematite (Fe2O3). Using density functional theory (DFT) calculations we explore the surface stability of different facets under relevant thermodynamic conditions. Additionally, we use transition state theory to describe different H reaction paths and their activation barriers. Keeping in mind the impact the description of the electronic structure may have on the considered quantities, the calculations were performed using both GGA-PBE and GGA-PBE+U. While our results indicate that both methods result in the same preferential reaction path, the electron localization from the (+U) term results in a significant reduction in the activation barrier.

Keywords: Hydrogen; Iron oxide; Reduction; Surfaces; DFT