Observation of ‘inverted peak’ during molecular oxygen reduction at Au electrode in alkaline media

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

“…The cathodic maximum and inverted peak has been observed by Ginzburg et al during the ORR at HMDE in aqueous solution containing Pb 2+ ion in which the cathodic maximum and the inverted peak have been considered to take place due to the precipitation of Pb compound on HMDE and the reductive desorption of thus-formed precipitate, respectively, [27]. The inverted peak has been also observed to result from the catalytic ORR at Au electrode in alkaline solution containing lead iodide where the in situ formed binary-adlayer of lead and iodine onto the Au electrode surface is considered to induce the reduction of O 2 (and H 2 O 2 ) in the anodic potential scan of the CV [43]. In this case, it is pointed out that a threshold condition on lead iodide concentration, potential range used for the measurement and its timescale may govern the inverted peak at Au electrode [43].…”

“…The inverted peak has been also observed to result from the catalytic ORR at Au electrode in alkaline solution containing lead iodide where the in situ formed binary-adlayer of lead and iodine onto the Au electrode surface is considered to induce the reduction of O 2 (and H 2 O 2 ) in the anodic potential scan of the CV [43]. In this case, it is pointed out that a threshold condition on lead iodide concentration, potential range used for the measurement and its timescale may govern the inverted peak at Au electrode [43].…”

“…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].…”

Indirect Electrochemical Cr(III) Oxidation in KOH Solutions at an Au Electrode: The Role of Oxygen Reduction Reaction

“…The oxygen reduction reaction carried out in oxygen-saturated 0.2 and 3.0 M KOH solutions with their corresponding blank curves under N 2 atmosphere are illustrated in Figure 2a and b, respectively. In Figure 2a, the peak at −0.18 V is assigned to the reduction of O 2 to HO 2 − via the overall reaction of ( 3) and ( 6) mentioned above, while the peak at −0.89 V to the reduction of HO 2 − to OH − , their corresponding counter reactions emerge at −0.06 and −0.63 V, respectively, 40 exhibiting quasi-reversible reaction characteristics. The ORR in 0.2 M KOH solution is attributed to a series 4e reduction with HO 2 − as an intermediate.…”

Electrochemically Fabricated Tin–Palladium Bimetallic Electrocatalyst for Oxygen Reduction Reaction in Acidic Media

“…[7][8][9][10] Modification of electrode surface by metal adatoms/nanoparticles has long been well known to potentially catalyze the ORR. [11][12][13][14][15][16][17][18][19][20][21][22] Pt has been widely used as an electrocatalyst for the ORR because of its high catalytic activity. However, its high price has encouraged the development of alternate platinum-free electrocatalysts for the ORR.…”