Relationship between the Composition and Structural Characteristics of Catalysts Based on Calcium Ferrites and Their Activity with Respect to Hydrogen

https://doi.org/10.1134/S1070363224060094

Using the methods of X-ray diffraction, Mössbauer spectroscopy, and temperature-programmed reduction with hydrogen, the relationship between the phase composition, structural characteristics of the phases, and the reactivity with respect to hydrogen was investigated for calcium ferrites-based catalysts. The catalyst samples were prepared via solid-state synthesis from CaO and Fe₂O₃ at 900 and 1000°C by varying the Fe₂O₃ content in the CaO–Fe₂O₃ system. The phase composition of the resultant samples corresponds to the CaO‒Ca₂Fe₂O₅, Ca₂Fe₂O₅‒CaFe₂O₄, and CaFe₂O₄‒α-Fe₂O₃ regions. In the CaO–Ca₂Fe₂O₅ samples the lattice parameters of Ca₂Fe₂O₅ and its activity with respect to hydrogen depend on the phase ratio. The activity of CaFe₂O₄ is higher in Ca₂Fe₂O₅‒CaFe₂O₄ compared to CaFe₂O₄‒α-Fe₂O₃ catalysts.https://doi.org/10.1134/S1070363224060094