fig4

Figure 4. TEM characterization of a Co-rich region of the LSCF surface after treatment in dry air at 800 °C. (A) Dark field STEM image of Co-rich surface nanocrystal. White circle marks the location of the SAD aperture used to acquire a diffraction pattern of the nanocrystal, and the cyan box marks the location of the STEM EDS elemental map (C-I); (B) TEM diffraction pattern of nanocrystal; d-spacing values match those of Co₃O₄ for d₁₁₁; (C-H) STEM-EDX elemental maps for Sr, S, La, Fe, Co, and O, displayed as relative atomic composition for each element; (I) combined elemental map for atomic fractions of Sr, S, La, Co, and Fe. ROI-4A and ROI-4B mark the regions where atomic composition was quantified using the STEM-EDS data, shown in Table 1.