Fig. 3: High-resolution N 1 s and Fe 2p XPS spectra.
From: A pyridinic Fe-N4 macrocycle models the active sites in Fe/N-doped carbon electrocatalysts
Fe-N-C (a and e), [(phen2N2)Fe]2O (b and f), [(Pc)Fe]2O (c and g), and [(OEP)Fe]2O (d and h). In the N 1s spectra, pyridinic and bridging nitrogens are depicted in blue, metal-coordinated nitrogens are depicted in magenta, graphitic/pyrrolic nitrogens are depicted as yellow, oxidized nitrogens are shown in purple and the π–π* satellites are shown in dark cyan. In the Fe 2p spectra, the 2p3/2 Fe(II) peak is shown in blue and the 2p3/2 Fe(III) peak is given in magenta. The Fe 2p1/2 peak is given in aqua blue. Multiplet peaks for the 2p3/2 and 2p1/2 peaks are given in green and dark cyan, respectively.
