Fig. 2: Coordination and electron structure analysis.

a XRD patterns, (b) N 1 s XPS spectra, and (c) P 2p XPS spectra of different catalysts. d XANES spectra of Fe-NPC and reference samples; e Linear fitting curve of Fe K-edge energy and Fe valence; f FT-EXAFS spectra; g WT-EXAFS contour plot of Fe-NPC; EXAFS spectra and fitting curves at (h) k space and (i) R space.