Fig. 2 | Nature Communications

Fig. 2

From: Synergistic Mn-Co catalyst outperforms Pt on high-rate oxygen reduction for alkaline polymer electrolyte fuel cells

Fig. 2

Structural characterizations of the Mn-Co catalyst. a Synchrotron X-ray diffraction (XRD) pattern, identifying the spinel cubic crystal structure with a lattice constant a = 8.2938 Å (inset). X-ray wavelength λ = 0.68876 Å. The raised baseline at around 10o is due to the carbon black support of the Mn-Co spinel (MCS). b X-ray absorption near-edge structure (XANES) spectra. The K-edge absorptions of Mn and Co were collected, each with three reference samples. The formal valences of Mn and Co were determined to be +2.76 and +2.56, respectively, corresponding to a stoichiometry of [Mn0.3Co0.7][Mn0.6Co0.4]2O4. c, d High-angle annular dark-field images from scanning transmission electron microscopy (HAADF-STEM) images of the MCS lattice, taken on zone axes of [110] and [112]. Models of lattice projection are provided, with a unit cell embedded in the picture, to interpret the atomic resolution images. See Supplementary Figs 8 and 9 for reasoning of the spot brightness. Elemental mapping results are provided in Supplementary Fig. 10

Back to article page