Determination of Fe2+/Fe3+ mole ratio based on the change of precursor lattice parameters of wustite based iron catalysts for the ammonia synthesis

• Published in: Polish journal of chemical technology 2019-09, Vol.21 (3), p.48-52
• Main Authors: Jurkowski, Artur, Lendzion-Bieluń, Zofia
• Format: Article
• Language: English
• Subjects: Ammonia; Catalysts; Chemical composition; Chemical synthesis; Crystal lattices; Crystal structure; Dependence; Emission analysis; Ferric ions; Ferric-ferrous ratio; Ferrous ions; Inductively coupled plasma; Iron; Lattice parameters; manganometry; Optical emission spectroscopy; Organic chemistry; Phase composition; Precursors; Titration; Wustite; wustite ammonia catalyst; wustite lattice parameter; XRD technique
• ISSN: 1509-8117; 1899-4741
• DOI: 10.2478/pjct-2019-0029

In the presented article, oxide forms of iron catalysts with the wustite structure and with a R = Fe /Fe molar ratio in the range from 3.78 to 8.16 were investigated. The chemical composition of the tested catalyst precursors was determined by inductively coupled plasma optical emission spectrometry (ICP-OES). The X-ray diffraction (XRD) technique was used to determine the phase composition and location of reflections characteristic of the Fe O phase. The molar ratio of iron ions R = Fe /Fe was determined by manganometric titration. The distribution of promoters in the structure of iron catalyst precursors with different R = Fe /Fe ratio was determined by a selective etching method. The dependence of the lattice parameter value in the crystal structure Fe O on the molar ratio R = Fe /Fe was determined. On the basis of the determined dependence, R can easily be calculated in catalyst precursors of the wustite structure.