Fig. 2. Experimentally determined pH values at the catalyst surface in different cell configurations and electrolytes. (A) Local pH at the surface of a gold catalyst in a CO2-saturated KHCO3 electrolyte, determined by rotating ring disc voltammetry. Reproduced from ref. 49 with permission from John Wiley and Sons. (B) Surface pH of a copper electrode in contact with CO2-saturated phosphate buffers determined by surface-enhanced infrared spectroscopy. Reproduced from ref. 62. Copyright 2019 ACS. (C) Local pH measurements in a continuous-flow bicarbonate electrolyzer with a silver foam cathode by Raman spectroscopy. Reproduced from ref. 51. Copyright 2020 ACS. (D) Local pH measurements with Raman spectroscopy on the surface of a Cu GDE in contact with a flowing 1 M KOH electrolyte and gas-phase CO2. Reproduced from ref. 52. Copyright 2020 ACS.
