Figure 3.

a) Pt‐tip voltammograms in the potential range between −0.8 and 0.8 V vs. Ag/AgCl/3 m KCl at a scan rate of 200 mV s⁻¹ in 1 m KOH. The Pt‐sensor is approached to a distance of approximately 100 nm over the Ag‐GDE, which is polarized to potentials between −0.1 and −1.57 V vs. Ag/AgCl/3 m KCl invoking CO₂RR and HER. b) Zoom‐in to the voltammograms displayed in (a), highlighting the shift of E ${}_{\mathrm{PtO}{}_{\mathrm{red}.}}$ in dependence of an increased cathodic potential applied to the Ag‐GDE. c) Peak potentials of E ${}_{\mathrm{PtO}{}_{\mathrm{red}.}}$ from the voltammograms in (a) as a function of applied E _Ag‐GDE. Stars refer to measurements at −0.1 V vs. Ag/AgCl/3 m KCl, the lower one directly after the measurement at −1.69 V and the higher one after further biasing the GDE for 15 min to −0.1 V.