Fig. 3: Structural properties of the Fe0.5Co0.5/MgO catalyst.
From: Highly loaded bimetallic iron-cobalt catalysts for hydrogen release from ammonia
a In situ XRD of the reduction process and (b) the corresponding phase composition transformations during reduction based on Rietveld refinement of the Mg(Fe0.5Co0.5)2O4, in (a) ➊ is MgFeCoO4 phase, ➋ is Mg(Fe,Co)O wüstite-like phase, ➌ is FeCo-bcc phase. c Representative BF-STEM image of the Fe0.5Co0.5/MgO catalyst and the FeCo alloy particle size distribution, which was determined by the evaluation of at least 400 particles (inset in (c)). The error bar represents the standard deviation through particle size statistical analysis. d The STEM image and (f) the corresponding EDS spectra collected at Area #1 and #2 (e) as well as EDX maps, which are related to K-line intensities from O, Fe, Co and Mg. (g) XRD patterns of the freshly reduced Fe/MgO and the spent Fe/MgO catalyst after reaction condition without exposure to the air. references: α-Fe (ICSD: 52258), Magnesium wüstite (ICSD: 181215), ε-Fe3N (ICSD: 79981). Operando XAS measurement of Fe0.5Co0.5/MgO catalyst during reaction: (h) XANES spectra at the Fe K-edge, (i) Fourier transformed k2-weighted EXAFS spectra in R-space at the Fe K-edge. The R-space EXAFS spectra are plotted without phase correction. The corresponding k-space EXAFS spectra were plotted in Supplementary Fig. 13. Source data are provided as a Source Data file.
