fig4

Figure 4. In situ Raman spectra of the species formed in the OER electrocatalyzed by (A) CoO_x-CO₃^2- and (B) IrCoO_x-CO₃^2-. (C) Ir 4f XPS spectra of IrO₂ and IrCoO_x-CO₃^2- after the OER stability testing, (D) Co 2p, and (E) O 1s XPS spectra of CoO_x-CO₃^2- and IrCoO_x-CO₃^2- after the OER stability testing.