Fig. 4.
In situ investigation of pre-OER behaviors of catalysts and schematic of the surface reconstruction and deprotonation process. (A) CVs of LSCAO (x = 0.0, 0.10 and 2.0) scanned in O2-saturated KOH (pH ≈ 12.5 to 14) at a scan rate of 10 mV s−1. DEMS signal ratios of 34O2 (16O18O) and 32O2 (16O16O) from the reaction products for 18O-labeled. (B) LSCO, (C) LSCAO-0.1, and (D) LSCAO-0.2 catalyst tests in H216O aqueous KOH electrolyte. In situ ATR-IR spectra recorded during the multi-potential steps for (E) LSCO (F) LSCAO-0.1 and (G) LSCAO-0.2. Proposed deprotonation mechanism before OER, shown for (H) LSCO and (I) LSCAO-0.2. The absorption band peaked at around 1,212 cm−1 is ascribed to the O−O stretching mode of surface-adsorbed superoxide (OOHad), the band at around 1,400 and 1,650 cm−1 are attributed to the O−O stretching mode of weakly adsorbed molecular oxygen (52, 53).