Steady state voltammetry at low electrolyte/reactant concentration ratios: what it means and what it does not mean

被引:28
作者
Amatore, C
Thouin, L
Bento, MF
机构
[1] Ecole Normale Super, Dept Chim, URA CNRS 1679, F-75231 Paris 05, France
[2] Univ Minho, Dept Quim, P-4719 Braga, Portugal
来源
JOURNAL OF ELECTROANALYTICAL CHEMISTRY | 1999年 / 463卷 / 01期
关键词
cell resistance; migration; impedance analysis; low electrolyte/reactant ratio; ohmic drop;
D O I
10.1016/S0022-0728(98)00431-8
中图分类号
O65 [分析化学];
学科分类号
070302 ; 081704 ;
摘要
Voltammetric measurements performed at low [electrolyte]/[reactant] ratios are affected by migrational transport, as well as by ohmic drop contributions. The latter depend on the current as well as on the charge of the initial electroactive species because the local electrolysis changes the ionic composition in the vicinity of the electrode. Extraction of thermodynamic or kinetic data from wave shapes and positions is thus impossible without correction of these ohmic drop components. This work extends a previous experimental approach for eliminating ohmic drop contributions from experimental voltammograms obtained at low [electrolyte]/[reactant] ratios, by combining impedance measurements and voltammetric data. The results presented here confirm our previous independent conclusions that when the reactant is neutral, the variation of ohmic drop along the voltammetric curve (which reflects the progressive ionic enrichment of the diffusion layer) cannot be predicted by considering diffusional/migrational transport alone, but also requires consideration of the influence of natural convection. (C) 1999 Elsevier Science S.A. All rights reserved.
引用
收藏
页码:45 / 52
页数:8
相关论文
共 16 条
[1]   ELECTROCHEMICAL KINETICS AT MICROELECTRODES .4. ELECTROCHEMISTRY IN MEDIA OF LOW IONIC-STRENGTH [J].
AMATORE, C ;
DEAKIN, MR ;
WIGHTMAN, RM .
JOURNAL OF ELECTROANALYTICAL CHEMISTRY, 1987, 225 (1-2) :49-63
[2]   Equivalence between microelectrodes of different shapes: Between myth and reality [J].
Amatore, C ;
Fosset, B .
ANALYTICAL CHEMISTRY, 1996, 68 (24) :4377-4388
[3]   MIGRATIONAL EFFECTS ON 2ND WAVES OF EE MECHANISMS UNDER STEADY-STATE OR QUASI-STEADY-STATE REGIMES [J].
AMATORE, C ;
BENTO, MF ;
MONTENEGRO, MI .
ANALYTICAL CHEMISTRY, 1995, 67 (17) :2800-2811
[4]   ELECTROCHEMICAL KINETICS AT MICROELECTRODES .5. MIGRATIONAL EFFECTS ON STEADY OR QUASI-STEADY-STATE VOLTAMMOGRAMS [J].
AMATORE, C ;
FOSSET, B ;
BARTELT, J ;
DEAKIN, MR ;
WIGHTMAN, RM .
JOURNAL OF ELECTROANALYTICAL CHEMISTRY, 1988, 256 (02) :255-268
[5]   Successive electron-transfers in low ionic strength solutions. Migrational flux coupling by homogeneous electron transfer reactions [J].
Amatore, C ;
Paulson, SC ;
White, HS .
JOURNAL OF ELECTROANALYTICAL CHEMISTRY, 1997, 439 (01) :173-182
[6]  
Amatore C, 1995, PHYSICAL ELECTROCHEM, P136
[7]   About potential measurements in steady state voltammetry at low electrolyte/analyte concentration ratios [J].
Bento, MF ;
Thouin, L ;
Amatore, C ;
Montenegro, MI .
JOURNAL OF ELECTROANALYTICAL CHEMISTRY, 1998, 443 (01) :137-148
[8]   Potential measurements in steady state voltammetry at low electrolyte/analyte concentration ratios. Role of convection on ohmic drop: a simplified model [J].
Bento, MF ;
Thouin, L ;
Amatore, C .
JOURNAL OF ELECTROANALYTICAL CHEMISTRY, 1998, 446 (1-2) :91-105
[9]  
BRUHAT G, 1967, ELECT COURS PHYSIQUE, P235
[10]   NATURAL-CONVECTION AT MICROELECTRODES [J].
GAO, XP ;
LEE, J ;
WHITE, HS .
ANALYTICAL CHEMISTRY, 1995, 67 (09) :1541-1545