RESEARCH / A0060
Dynamic La Leaching Activates Oxygen‐Ligand Holes to Stabilize Mn Oxides for Acidic Oxygen Evolution
Read the original paper · 10.1002/adfm.76721 ↗
Source figures may contain other techniques and soft X-ray spectra. C, N and O measurements are outside our current hard-XAFS testing range.
FIGURE 3 Operando structural characterizations of catalysts. (a, d) Operando normalized Mn K-edge XANES spectra of (a) γ-MnO2 and (d) La0.1Mn0.9Ox collected sequentially from OCV to 1.5 V (versus RHE, without iR correction). (b, e) Corresponding Fourier-transformed k2-weighted Mn K-edge EXAFS spectra of (b) γ-MnO2 and (e) La0.1Mn0.9Ox. M, metal (Mn and La). (c) Intensity ratio of corner-sharing to edge-sharing MnO6 octahedra extracted from EXAFS fitting for γ-MnO2 and La0.1Mn0.9Ox as a function of potential. (f, g) Operando Raman spectra of (f) γ-MnO2 and (g) La0.1Mn0.9Ox collected sequentially from OCV to 1.6 V (versus RHE, without iR correction). (h) Potential-dependent shift of the Raman band for γ-MnO2 and La0.1Mn0.9Ox.
FIGURE 4 Structural evolution of catalysts after the OER. (a) Normalized Mn K-edge XANES spectra of γ-MnO2 and La0.1Mn0.9Ox before and after the OER for 1 h. (b) Corresponding Fourier-transformed k2-weighted Mn K-edge EXAFS spectra. (c) Intensity ratio of corner-sharing to edge-sharing MnO6 octahedra extracted from EXAFS fitting for γ-MnO2 and La0.1Mn0.9Ox before and after the OER. (d) Raman spectra of γ-MnO2 and La0.1Mn0.9Ox before and after the OER. (e) Raman band shift of γ-MnO2 and La0.1Mn0.9Ox before and after the OER. (f) Schematic illustration of the structural evolution of γ-MnO2 under acidic OER conditions.