CV obtained during the in situ experiment with the Pt black electrode at 25 C using the 5 mol dm–3 (5 M) H3PO3 electrolyte. The dashed lines indicate the selected potentials at which in situ PK-edge XANES spectra were recorded. Pa denotes the maximum current density of the electrochemical oxidation of H3PO3 to H3PO4 via eq 5. The green arrows illustrate the current density response during the positive-going potential sweep, while the orange arrows show the current density response during the negative-going potential sweep. The CV recording started at the potential of +0.05 VRHE with the positive-going potential sweep, using a scan rate of 50 mV s–1. The inset graph shows the chronoamperometry (CA) current density profiles during the potential bias at +0.8 VRHE, +0.9 VRHE, and +1.0 VRHE.
