Fig. 3: XPS analysis of the Co-qPyH|m-TiO₂ electrode.

Before (blue trace) and after (orange trace) 2 h of electrolysis at −0.51 V vs. RHE in 0.1 M KHCO₃ electrolyte saturated with CO₂ (pH = 6.8). Data show binding energies for Co_2p (a), N_1s (b), and P_2p (c).