“Inverted” peaks and current oscillations in cyclic voltammetry

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

“…Comproportionation process, involving adsorption at the HMDE, of nitroprusside (NP) at pH 5.5 produced inverted peak that was observed by Simao et al [3]. Ginzburg et al [4] detected it at the same electrode with the growing concentration of oxygen (O 2 ) or hydrogen peroxide (H 2 O 2 ) in aqueous neutral media containing 2.0 mM Pb(NO 3 ) 2 . Green et al [5] observed inverted peak during underpotential deposition (UPD) of Pb 2+ on Au(1 1 1) electrode in O 2 -containing 0.05 M HClO 4 solution.…”

“…Several authors have reported inverted peaks obtained at Hg electrodes [1][2][3][4][5][6][7][8] for different electrochemical processes. For instance, Blazquez and co-workers [1] observed inverted peak in the electrochemical reduction of pyridine-4-aldoxime (PA) in acidic buffer solution at a hanging mercury dropping electrode (HMDE) and explained in terms of the adsorption of neutral intermediates formed by the reduction of PA. Camacho et al [2] found inverted peak in the electrochemical reduction of 4, 4 -bipyridne (BP) under optimized conditions.…”

Increased sensitivity of anodic stripping voltammetry at the hanging mercury drop electrode by ultracathodic deposition

“…This is consistent with a peak in current that appears at around −2.0 V in a linear sweep from −1.0 to −2.5 V vs Ag/AgCl (data not shown). Oscillations in mercury electrodes are known in literature [23][24][25][26][27][28][29][30]. Usually they are related to similar phenomena to those observed in the maxima of first kind in classical polarography, which remarkably is mostly observed at cathodic polarizations [30][31][32].…”

In situ CCD video and voltammetric studies on enhanced cathodic peak observed at a hanging mercury drop electrode during consecutive two one-electron redox reactions in aprotic solutions

“…1C) often appears to be smaller ðI c2 p =I c1 p < 1) and larger ðI c2 p =I c1 p > 1) than unity at the solid plane electrode [3,14] and the HMDE [2][3][4][5], respectively. Such an enhanced I c2 p that may be recognized as an unexpected event concerning the electrode kinetics and electroanalysis at the HMDE has been hitherto claimed to result from the electrochemical processes involving the chemical reaction [1,14,15], adsorption [2,14], multielectron transfer and chemical complications [5] and the streaming phenomena of the HMDE [1][2][3].…”

“…In the past some decades, a number of peculiarities [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15] concerning the cyclic voltammograms (CVs) obtained at a hanging mercury drop electrode (HMDE) in aprotic solutions and ionic liquids [9] (e.g., cyclic voltammetric anodic current oscillation (CVACO) [1][2][3][4][5][6][7][8][9][10][11], inverted peak [3,11,12] and larger current of the second cathodic peak than that of the first one of a stepwise one-electron redox reaction [1][2][3][4][5]14,15]) have been reported. These eccentric phenomena especially the CVACO that has been visualized to originate from a novel circular motion [10] at the HMDE|solution interface due to the familiar polarographic streaming phenomena [1,[6][7][8][9][10][11]16] have been reported to be fundamentally very interesting...…”