RESEARCH / A0427
Quantifying π-electron delocalization as a universal descriptor for ORR activity in MN4 catalysts. Journal of Catalysis
Read the original paper · 10.1016/j.jcat.2025.116093 ↗
Source figures may contain other techniques and soft X-ray spectra. C, N and O measurements are outside our current hard-XAFS testing range.
Fig. 2. The correlation between the electronic structure of metal sites and the nature of connected carbon planes. (a) Fe K-edge XANES spectra of FePc/C (blue line) with references of Fe foil, FePc, FeO, and Fe2O3. (b) Approximate valence of Fe in FePc/C and FePc samples. (c) R-space EXAFS spectra of M K-edge for MPc/C catalysts. (d) Schematic diagram of FWHM and Δπ, the computation of Δπ is described in detail in the Supporting Note. (e) The linear relationship between Δπ of graphitic carbon and valence state of metal center in MPc/C. (f) Schematic diagram of the influence of Δπ on the d-orbital energy level of metal centers. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)