Electrochemistry of dioxygen activation in the presence of adenine

Two-electron quasi-reversible reduction of dioxygen at HMDE in ionic liquids: Observation of cathodic maximum and inverted peak

“…Generally, the occurrence of inverted peak has been explained in terms of surface phenomena (adsorption-desorption) and assumed to indicate the occurrence of a regenerative process leading to the catalytic process [24]. The inverted peak has been observed during catalytic electrochemical processes [4,28,31,[38][39][40][41][42][43], e.g., ORR [4,28,43] at HMDE and solid electrodes (e.g., Au and Pt electrodes) in aqueous and non-aqueous solutions, the reduction of vitamin U and H + , and the reduction of nitroprusside and oximes [37][38][39][40][41]. Roman et al have observed the cathodic maxima and inverted peak during the reduction of pyridine-4-aldoxime at HMDE [37].…”

“…Thus, the maximum during the cathodic scan and inverted peak during the anodic scan are accompanied by strong downward and upward motions, respectively, and it should be noted here that these motions are opposite in direction to those inherently associated with usual cathodic and anodic processes in this potential range (described above). The above-mentioned observations may imply that the cathodic maximum and inverted peak are due to the adsorptionÀdesorption phenomena of the species generated during the ORR at HMDE (i.e., maxima of the third kind) [25][26][27][28][34][35][36][37][38][39][40][41][42].…”