Power-to-X Processes with Synthetic Iron Oxides

Iron oxide redox cycling presents a pathway to integrate electrolytic hydrogen production and storage. Furthermore, utilizing CO₂ with iron-based materials, enables synthesis gas production without noble metal catalysts, exhibiting high thermochemical stability. Experimental data reveals that a hydrogen flow of 0.07 m³ h⁻¹ achieves ≈45% reduction. Doubling the H₂ flow enhances reduction by over 20%. Complete reduction necessitates 4.25 times the stoichiometric H₂; complete oxidation requires 4.29 times stoichiometric CO₂, with 0.015 m³ h⁻¹ CO₂ at 900 °C showing higher efficiency. While H₂ reduction is near-complete across tested binders, CO₂ reoxidation is limited. Notably, a 20% aluminous binder facilitates full oxygen exchange over 20 redox cycles, albeit with gradual kinetic deceleration. The versatility of CO₂ sources allows for the production of sustainable chemicals and fuels, facilitating climate-neutral processes when coupled with green hydrogen. These findings underscore the potential of iron oxide redox chemistry in advancing sustainable energy and chemical synthesis.