Electrochemical (EC) cell at HIPPIE beamline. Liquid microjet (top left) emerging from the end of a 20 µm glass nozzle into an opening of a `catcher'. In the foreground an analyser cone with 300 µm opening can be seen. Dip-and-pull setup (top right) showing sample (working electrode), Ag/AgCl reference and N-doped diamond counter-electrodes from right to left. The sample is in XPS position with the mirror reflection of the analyser cone being visible on the sample's surface. Pt 4f (bottom left) and O 1s (bottom right) XP spectra measured in the setup shown in the top-right panel at 24 mbar of H2O and room temperature. Blue (red) curves correspond to +0.5 V (−0.5 V) applied potential. Thickness of KOH electrolyte layer estimated by the attenuation of Pt signal (vacuum spectrum is not shown) is ca 20 nm. Each spectrum took ca 3 min to record. hν = 1800 eV, photon energy = 100 eV, exit slit 100 µm. Potentials are with respect to Ag/AgCl reference electrode.