Fig. 6. Linear sweep voltammograms of 1|NiO and 2|NiO immersed in aqueous 0.1 M KCl electrolyte (pH 3). The potential was swept from E_appl = 0 to –0.6 V vs. Ag/AgCl (3.0 M NaCl) in the dark and under simulated light illumination (AM1.5, 100 mW cm^–2).