Fig. 2.

In situ Raman spectra and current densities during the CO redox at Cu(100). (A–C) Potential-dependent EC-SHINERS spectra recorded from Cu(100) in the presence of (A) ¹²CO and (B) ¹³CO and (C) with D₂O as electrolyte in 0.1 M CsOH/OD solutions (pH = 13). These solutions are saturated with ¹²CO or ¹³CO gases. The Cu, ¹²C, ¹³C, and O atoms are presented in orange, gray, black, and red colors, respectively. All spectra are normalized to the intensity of the 105 cm⁻¹ bands. a.u., arbitrary units; OCP, open circuit potential. (D) The total current density of Cu(100) under different conditions. (E) Corresponding Raman shifts for C=O stretching modes on Cu(100) under different conditions. a.u. arbitrary units.