Figure 3.

In situ Raman and quasi‐in situ X‐ray absorption spectroscopy of LiMnBPO/FTO under alkaline water oxidation. a) Raman spectra of as‐deposited and post catalytic films suggested complete surface structural transformation under water oxidation potentials. b) Time‐resolved in situ Raman spectra of as‐deposited films at various time intervals evidenced the formation of K‐/Li‐birnessite like MnO _x active phase over the surface of the precatalyst. The essential marker bands are represented with ν₁, ν₂, ν₃, ν₄, and ν₅, respectively. c) XANES and d) Fourier transformed EXAFS measured at the Mn K‐edge of as‐prepared powder, as‐deposited, and the film after water oxidation catalysis further validate the results obtained from Raman spectroscopy. EXAFS simulation parameters and experimental data in k‐space are shown in Tables S9 and S10 and Figure S47 in the Supporting Information.