The interfacial Galvani potential difference at the polarised aqueous|TFT interface (Δ o w 𝜙) was controlled externally using an Autolab PGSTAT204 from Metrohm (Netherlands), in conjunction with NOVA software version 2.1.2. and a specialised four-electrode electrochemical cell. A detailed schematic of the latter is shown in Supplementary Fig. and images are provided in Fig. . Two reference electrodes positioned on different sides of the aqueous|TFT interface measured the potential difference across the interface. Platinum counter electrodes placed in each phase allowed the flow of electric current. The geometrical surface area of the aqueous|TFT interface was ~1.66 cm 2 . To enhance the diffusion of the Ce 4+ oxidant in the aqueous phase, a homemade stirrer was positioned approx. 2 cm above the water|TFT interface. A glass capillary with a U-bend was used as the stirrer, which was attached to an electric motor that operated at 240 rpm. A theoretical background to such experiments at an ITIES can be found in several articles and book chapters. All electrochemical measurements were carried out in ambient aerobic conditions at room temperature (RT, 21 o C). The methodology to calibrate all electrochemical data obtained at the ITIES to the Galvani potential scale is described in Supplementary section 2.