Fig. 4. In situ SRIR measurements in 0.1 M HClO₄ (pH = 1). The loading of catalysts is 1 mg cm⁻², and the solution resistance 2.2 Ω.

In situ SRIR spectroscopy measurements in the range 1700–700 cm⁻¹ at various potentials for a TS–Ir/MnO₂ and b IrO₂. Isotope-labeling in situ SRIR spectroscopy measurements in the range 1700–700 cm⁻¹ at various potentials for c TS–Ir/MnO₂ and e IrO₂. d In situ SRIR spectra generated under no- and isotope-labeling conditions at typical potentials of 1.00 and 1.35 V for TS–Ir/MnO₂. f In situ SRIR spectra generated under no- and isotope-labeling conditions at typical potentials of 1.00 and 1.50 V for IrO₂.