1
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Levey KJ, Edwards MA, White HS, Macpherson JV. Simulation of the cyclic voltammetric response of an outer-sphere redox species with inclusion of electrical double layer structure and ohmic potential drop. Phys Chem Chem Phys 2023; 25:7832-7846. [PMID: 36857676 DOI: 10.1039/d3cp00098b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/22/2023]
Abstract
A finite-element model has been developed to simulate the cyclic voltammetric (CV) response of a planar electrode for a 1e outer-sphere redox process, which fully accounts for cell electrostatics, including ohmic potential drop, ion migration, and the structure of the potential-dependent electric double layer. Both reversible and quasi-reversible redox reactions are treated. The simulations compute the time-dependent electric potential and ion distributions across the entire cell during a voltammetric scan. In this way, it is possible to obtain the interdependent faradaic and non-faradaic contributions to a CV and rigorously include all effects of the electric potential distribution on the rate of electron transfer and the local concentrations of the redox species Oz and Rz-1. Importantly, we demonstrate that the driving force for electron transfer can be different to the applied potential when electrostatic interactions are included. We also show that the concentrations of Oz and Rz-1 at the plane of electron transfer (PET) significantly depart from those predicted by the Nernst equation, even when the system is characterised by fast electron transfer/diffusion control. A mechanistic rationalisation is also presented as to why the electric double layer has a negligible effect on the CV response of such reversible systems. In contrast, for quasi-reversible electron transfer the concentrations of redox species at the PET are shown to play an important role in determining CV wave shape, an effect also dependant on the charge of the redox species and the formal electrode potential of the redox couple. Failure to consider electrostatic effects could lead to incorrect interpretation of electron-transfer kinetics from the CV response. Simulated CVs at scan rates between 0.1 and 1000 V s-1 are found to be in good agreement with experimental data for the reduction of 1.0 mM Ru(NH3)63+ at a 2 mm diameter gold disk electrode in 1.0 M potassium nitrate.
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Affiliation(s)
- Katherine J Levey
- Department of Chemistry, University of Warwick, Coventry, CV4 7AL, UK. .,Centre for Diamond Science and Technology, University of Warwick, Coventry, CV4 7AL, UK
| | - Martin A Edwards
- Department of Chemistry & Biochemistry, University of Arkansas, Fayetteville, AR 72701, USA
| | - Henry S White
- Department of Chemistry, University of Utah, 315 South 1400 East, Salt Lake City, UT 84112, USA.
| | - Julie V Macpherson
- Department of Chemistry, University of Warwick, Coventry, CV4 7AL, UK. .,Centre for Diamond Science and Technology, University of Warwick, Coventry, CV4 7AL, UK
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2
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Luo X, Yu Q, Liu Y, Gai W, Ye L, Yang L, Cui Y. Closed-Loop Diabetes Minipatch Based on a Biosensor and an Electroosmotic Pump on Hollow Biodegradable Microneedles. ACS Sens 2022; 7:1347-1360. [PMID: 35442623 DOI: 10.1021/acssensors.1c02337] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Developing a miniaturized, low-cost, and smart closed-loop system for diabetes could significantly improve life quality and benefit millions of people. Conventional closed-loop devices are large in size and exorbitant. Here, we unprecedentedly demonstrate an electrically controlled flexible closed-loop patch for continuous diabetes management by integrating hollow biodegradable microneedles with a biosensing device and an electroosmotic pump. The hollow microneedles were fabricated using a combination of soft lithography and micromachining. The outer layer of the microneedles was functionalized to serve as a biosensing device for the in situ sensitive and accurate monitoring of interstitial glucose. The inner layer of the microneedles was integrated with a flexible electroosmotic pump to deliver insulin, and the delivery rate was electrically controlled by the glucose level from the biosensing device. The closed-loop system successfully stabilized the blood glucose levels of diabetic rats in a normal and safe range. The system is painless, miniaturized, cost-effective, and flexible. It is anticipated that it could open up exciting new avenues for fundamental studies of new closed-loop devices as well as practical applications for diabetes management.
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Affiliation(s)
- Xiaojin Luo
- School of Materials Science and Engineering, Peking University, Beijing 100871, P. R. China
| | - Qi Yu
- Renal Division, Peking University First Hospital; Peking University Institute of Nephrology; Key Laboratory of Renal Disease, Ministry of Health of China; Key Laboratory of Chronic Kidney Disease Prevention and Treatment (Peking University), Ministry of Education, Beijing 100034, P. R. China
| | - Yiqun Liu
- School of Materials Science and Engineering, Peking University, Beijing 100871, P. R. China
| | - Weixin Gai
- School of Integrated Circuits, Peking University, Beijing 100871, P. R. China
| | - Le Ye
- School of Integrated Circuits, Peking University, Beijing 100871, P. R. China
| | - Li Yang
- Renal Division, Peking University First Hospital; Peking University Institute of Nephrology; Key Laboratory of Renal Disease, Ministry of Health of China; Key Laboratory of Chronic Kidney Disease Prevention and Treatment (Peking University), Ministry of Education, Beijing 100034, P. R. China
| | - Yue Cui
- School of Materials Science and Engineering, Peking University, Beijing 100871, P. R. China
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3
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Pireddu G, Svir I, Amatore C, Oleinick A. Modelling diffusion at random arrays of electrodes: Revisiting the Voronoi tessellation concept. Electrochim Acta 2021. [DOI: 10.1016/j.electacta.2020.137338] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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4
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Moazzenzade T, Yang X, Walterbos L, Huskens J, Renault C, Lemay SG. Self-Induced Convection at Microelectrodes via Electroosmosis and Its Influence on Impact Electrochemistry. J Am Chem Soc 2020; 142:17908-17912. [PMID: 33044066 PMCID: PMC7582615 DOI: 10.1021/jacs.0c08450] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
![]()
Faradaic
reactions at low supporting electrolyte concentrations
induce convection via electroosmotic flows. Here we combine finite-element
simulations and electrochemical measurements on microparticles at
ultramicroelectrodes to explore this effect. We show that convection
becomes the dominant form of mass transport for experiments at low
salt concentrations, violating the common assumption that convection
can be neglected.
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Affiliation(s)
- Taghi Moazzenzade
- MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
| | - Xiaojun Yang
- MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
| | - Luc Walterbos
- MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
| | - Jurriaan Huskens
- MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
| | - Christophe Renault
- Physique de la Matière Condensée, Ecole Polytechnique, CNRS, IP Paris, 91128 Palaiseau, France
| | - Serge G Lemay
- MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
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5
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Kostiuchenko Z, Cui JZ, Lemay SG. Electrochemistry in Micro- and Nanochannels Controlled by Streaming Potentials. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2020; 124:2656-2663. [PMID: 32030113 PMCID: PMC6996092 DOI: 10.1021/acs.jpcc.9b08584] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/10/2019] [Revised: 12/20/2019] [Indexed: 06/10/2023]
Abstract
Fluid and charge transport in micro- and nanoscale fluidic systems are intrinsically coupled via electrokinetic phenomena. While electroosmotic flows and streaming potentials are well understood for externally imposed stimuli, charge injection at electrodes localized inside fluidic systems via electrochemical processes remains to a large degree unexplored. Here, we employ ultramicroelectrodes and nanogap electrodes to study the subtle interplay between ohmic drops, streaming currents, and faradaic processes in miniaturized channels at low concentrations of supporting electrolyte. We show that electroosmosis can, under favorable circumstances, counteract the effect of ohmic losses and shift the apparent formal potential of redox reactions. This interplay can be described by simple circuit models, such that the results described here can be adapted to other micro- and nanofluidic electrochemical systems.
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6
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Renault C, Lemay SG. Electrochemical Collisions of Individual Graphene Oxide Sheets: An Analytical and Fundamental Study. ChemElectroChem 2020; 7:69-73. [PMID: 31998598 PMCID: PMC6973065 DOI: 10.1002/celc.201901606] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Revised: 11/25/2019] [Indexed: 11/12/2022]
Abstract
We propose an analytical method based on electrochemical collisions to detect individual graphene oxide (GO) sheets in an aqueous suspension. The collision rate is found to exhibit a complex dependence on redox mediator and supporting electrolyte concentrations. The analysis of multiple collision events in conjunction with numerical simulations allows quantitative information to be extracted, such as the molar concentration of GO sheets in suspension and an estimate of the size of individual sheets. We also evidence by numerical simulation the existence of edge effects on a 2D blocking object.
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Affiliation(s)
- Christophe Renault
- MESA+ Institute for NanotechnologyUniversity of Twente P.O. Box 1277500 AEEnschedeThe Netherlands
- Physique de la Matière CondenséeEcole Polytechnique, CNRS, IP Paris91128PalaiseauFrance
| | - Serge G. Lemay
- MESA+ Institute for NanotechnologyUniversity of Twente P.O. Box 1277500 AEEnschedeThe Netherlands
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7
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8
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Li X, Batchelor-McAuley C, Laborda E, Compton RG. Aqueous Voltammetry in the Near Absence of Electrolyte. Chemistry 2017; 23:15222-15226. [PMID: 28876501 DOI: 10.1002/chem.201703525] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Indexed: 11/09/2022]
Abstract
In order to minimize the incidence of the CO2 hydrolysis and conduct aqueous electrochemistry in the virtual absence of electrolyte, a novel methodology is developed to achieve the near minimum conductivity (≈60 nS cm-1 ) for an aqueous solution through in situ deionization with ion exchange resin beads. Aqueous electrochemistry studying the oxidations of platinum, ferrocenemethanol, and hydrogen (H2 ) were conducted in the near complete absence of trace ionic species at a platinum microelectrode (d=10 μm). Both surface and solution phase electrochemical reactions were clearly observed, indicating that under these conditions there is a sufficiently compressed double layer for an interfacial electron transfer to be driven and the iR effects are significantly smaller than theoretically expected.
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Affiliation(s)
- Xiuting Li
- Department of Chemistry, Physical & Theoretical Chemistry Laboratory, Oxford University, Oxford, OX1 3QZ, UK
| | | | - Eduardo Laborda
- Departamento de Química Física, Facultad de Química, Universidad de Murcia, 30100, Murcia, Spain
| | - Richard G Compton
- Department of Chemistry, Physical & Theoretical Chemistry Laboratory, Oxford University, Oxford, OX1 3QZ, UK
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9
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Nguyen VQ, Schaming D, Tran DL, Lacroix JC. Ordered Nanoporous Thin Films by Nanosphere Lithography and Diazonium Electroreduction: Simple Elaboration of Ultra-Micro-Electrode Arrays. ChemElectroChem 2016. [DOI: 10.1002/celc.201600420] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Van-Quynh Nguyen
- Université Paris Diderot, Sorbonne Paris Cité, ITODYS, UMR 7086 CNRS; 15 rue Jean-Antoine de Baïf 75205 Paris Cedex 13 France
- Department of Advanced Materials Science and Nanotechnology; University of Science and Technology of Hanoi (USTH); 18 Hoang Quoc Viet Hanoi Vietnam
| | - Delphine Schaming
- Université Paris Diderot, Sorbonne Paris Cité, ITODYS, UMR 7086 CNRS; 15 rue Jean-Antoine de Baïf 75205 Paris Cedex 13 France
| | - Dai Lam Tran
- Graduate University of Science and Technology; Vietnam Academy of Science and Technology; 18 Hoang Quoc Viet Hanoi Vietnam
| | - Jean-Christophe Lacroix
- Université Paris Diderot, Sorbonne Paris Cité, ITODYS, UMR 7086 CNRS; 15 rue Jean-Antoine de Baïf 75205 Paris Cedex 13 France
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10
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Gunderson C, Zhang B. Microfabricated, Massive Electrochemical Arrays of Uniform Ultramicroelectrodes. J Electroanal Chem (Lausanne) 2016; 781:174-180. [PMID: 28579929 DOI: 10.1016/j.jelechem.2016.10.054] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
We report the preparation and electrochemical characterization of massive electrochemical arrays containing as many as 110,000 highly uniform ultramicroelectrodes (UMEs). These arrays were microfabricated using conventional photolithography techniques on a gold-coated silicon chip in a simple three-step method. Photoresist polymer was used as an effective insulating matrix to define 2 μm, 3 μm, and 4 μm diameter circular UMEs across a 1 × 1 mm2 area. The UME arrays are high uniform and contain tens of thousands of active disk-shape UMEs slightly recessed in thin films of photoresist. These arrays were tested with cyclic voltammetry and copper electrodeposition to assess the adhesion of photoresist to the gold surface as well as to examine their electrochemical activity. Numerical simulations were performed to further validate their electrochemical response. These UME arrays can be a useful platform for fundamental understanding molecular transport in uniform electrochemical arrays and designing highly-sensitive electroanalytical sensors.
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Affiliation(s)
- Christopher Gunderson
- Department of Chemistry, University of Washington, Seattle Washington 98195 United States
| | - Bo Zhang
- Department of Chemistry, University of Washington, Seattle Washington 98195 United States
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11
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Polcari D, Dauphin-Ducharme P, Mauzeroll J. Scanning Electrochemical Microscopy: A Comprehensive Review of Experimental Parameters from 1989 to 2015. Chem Rev 2016; 116:13234-13278. [PMID: 27736057 DOI: 10.1021/acs.chemrev.6b00067] [Citation(s) in RCA: 213] [Impact Index Per Article: 26.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- David Polcari
- Department
of Chemistry, McGill University, 801 Sherbrooke Street West, Montreal, Quebec Canada, H3A 0B8
| | - Philippe Dauphin-Ducharme
- Department
of Chemistry, McGill University, 801 Sherbrooke Street West, Montreal, Quebec Canada, H3A 0B8
| | - Janine Mauzeroll
- Department
of Chemistry, McGill University, 801 Sherbrooke Street West, Montreal, Quebec Canada, H3A 0B8
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12
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Aoki KJ. Voltammetry at a single nano-electrode by varying electrode diameters: Review. J Electroanal Chem (Lausanne) 2016. [DOI: 10.1016/j.jelechem.2016.03.029] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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13
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Ma C, Xu W, Wichert WRA, Bohn PW. Ion Accumulation and Migration Effects on Redox Cycling in Nanopore Electrode Arrays at Low Ionic Strength. ACS NANO 2016; 10:3658-64. [PMID: 26910572 DOI: 10.1021/acsnano.6b00049] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Ion permselectivity can lead to accumulation in zero-dimensional nanopores, producing a significant increase in ion concentration, an effect which may be combined with unscreened ion migration to improve sensitivity in electrochemical measurements, as demonstrated by the enormous current amplification (∼2000-fold) previously observed in nanopore electrode arrays (NEA) in the absence of supporting electrolyte. Ionic strength is a key experimental factor that governs the magnitude of the additional current amplification (AFad) beyond simple redox cycling through both ion accumulation and ion migration effects. Separate contributions from ion accumulation and ion migration to the overall AFad were identified by studying NEAs with varying geometries, with larger AFad values being achieved in NEAs with smaller pores. In addition, larger AFad values were observed for Ru(NH3)6(3/2+) than for ferrocenium/ferrocene (Fc(+)/Fc) in aqueous solution, indicating that coupling efficiency in redox cycling can significantly affect AFad. While charged species are required to observe migration effects or ion accumulation, poising the top electrode at an oxidizing potential converts neutral species to cations, which can then exhibit current amplification similar to starting with the cation. The electrical double layer effect was also demonstrated for Fc/Fc(+) in acetonitrile and 1,2-dichloroethane, producing AFad up to 100× at low ionic strength. The pronounced AFad effects demonstrate the advantage of coupling redox cycling with ion accumulation and migration effects for ultrasensitive electrochemical measurements.
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Affiliation(s)
- Chaoxiong Ma
- Department of Chemistry and Biochemistry and ‡Department of Chemical and Biomolecular Engineering, University of Notre Dame , Notre Dame, Indiana 46556, United States
| | - Wei Xu
- Department of Chemistry and Biochemistry and ‡Department of Chemical and Biomolecular Engineering, University of Notre Dame , Notre Dame, Indiana 46556, United States
| | - William R A Wichert
- Department of Chemistry and Biochemistry and ‡Department of Chemical and Biomolecular Engineering, University of Notre Dame , Notre Dame, Indiana 46556, United States
| | - Paul W Bohn
- Department of Chemistry and Biochemistry and ‡Department of Chemical and Biomolecular Engineering, University of Notre Dame , Notre Dame, Indiana 46556, United States
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14
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Ngamchuea K, Eloul S, Tschulik K, Compton RG. Advancing from Rules of Thumb: Quantifying the Effects of Small Density Changes in Mass Transport to Electrodes. Understanding Natural Convection. Anal Chem 2015; 87:7226-34. [DOI: 10.1021/acs.analchem.5b01293] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Kamonwad Ngamchuea
- Department of Chemistry, Physical & Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QZ, United Kingdom
| | - Shaltiel Eloul
- Department of Chemistry, Physical & Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QZ, United Kingdom
| | - Kristina Tschulik
- Department of Chemistry, Physical & Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QZ, United Kingdom
| | - Richard G. Compton
- Department of Chemistry, Physical & Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QZ, United Kingdom
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15
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Planar diffusion to macro disc electrodes—what electrode size is required for the Cottrell and Randles-Sevcik equations to apply quantitatively? J Solid State Electrochem 2014. [DOI: 10.1007/s10008-014-2664-z] [Citation(s) in RCA: 96] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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16
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Eloul S, Compton RG. Shielding of a Microdisc Electrode Surrounded by an Adsorbing Surface. ChemElectroChem 2014. [DOI: 10.1002/celc.201400005] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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17
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Zhang C, Aoki KJ, Chen J, Nishiumi T. Blocking of two-electron reduction of non-charged species in the absence of supporting electrolyte at nanoelectrodes. J Electroanal Chem (Lausanne) 2013. [DOI: 10.1016/j.jelechem.2013.09.023] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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18
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Zhang B, Fan L, Zhong H, Liu Y, Chen S. Graphene Nanoelectrodes: Fabrication and Size-Dependent Electrochemistry. J Am Chem Soc 2013; 135:10073-80. [DOI: 10.1021/ja402456b] [Citation(s) in RCA: 83] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Affiliation(s)
- Bo Zhang
- Key Laboratory of Analytical Chemistry for Biology
and Medicine (Ministry of Education), Hubei Key Laboratory of Electrochemical
Power Sources, Department of Chemistry, Wuhan University, Wuhan, People’s Republic of China
| | - Lixin Fan
- Key Laboratory of Analytical Chemistry for Biology
and Medicine (Ministry of Education), Hubei Key Laboratory of Electrochemical
Power Sources, Department of Chemistry, Wuhan University, Wuhan, People’s Republic of China
| | - Huawei Zhong
- Key Laboratory of Analytical Chemistry for Biology
and Medicine (Ministry of Education), Hubei Key Laboratory of Electrochemical
Power Sources, Department of Chemistry, Wuhan University, Wuhan, People’s Republic of China
| | - Yuwen Liu
- Key Laboratory of Analytical Chemistry for Biology
and Medicine (Ministry of Education), Hubei Key Laboratory of Electrochemical
Power Sources, Department of Chemistry, Wuhan University, Wuhan, People’s Republic of China
| | - Shengli Chen
- Key Laboratory of Analytical Chemistry for Biology
and Medicine (Ministry of Education), Hubei Key Laboratory of Electrochemical
Power Sources, Department of Chemistry, Wuhan University, Wuhan, People’s Republic of China
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20
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Affiliation(s)
- Stephen M. Oja
- Department of Chemistry, University of Washington, Seattle, Washington 98195,
United States
| | - Marissa Wood
- Department of Chemistry, University of Washington, Seattle, Washington 98195,
United States
| | - Bo Zhang
- Department of Chemistry, University of Washington, Seattle, Washington 98195,
United States
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21
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Belding SR, Compton RG. Cyclic voltammetry in the absence of excess supporting electrolyte: The effect of analyte charge. J Electroanal Chem (Lausanne) 2012. [DOI: 10.1016/j.jelechem.2012.07.023] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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22
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Quantitative nanoscale visualization of heterogeneous electron transfer rates in 2D carbon nanotube networks. Proc Natl Acad Sci U S A 2012; 109:11487-92. [PMID: 22635266 DOI: 10.1073/pnas.1203671109] [Citation(s) in RCA: 84] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Carbon nanotubes have attracted considerable interest for electrochemical, electrocatalytic, and sensing applications, yet there remains uncertainty concerning the intrinsic electrochemical (EC) activity. In this study, we use scanning electrochemical cell microscopy (SECCM) to determine local heterogeneous electron transfer (HET) kinetics in a random 2D network of single-walled carbon nanotubes (SWNTs) on an Si/SiO(2) substrate. The high spatial resolution of SECCM, which employs a mobile nanoscale EC cell as a probe for imaging, enables us to sample the responses of individual portions of a wide range of SWNTs within this complex arrangement. Using two redox processes, the oxidation of ferrocenylmethyl trimethylammonium and the reduction of ruthenium (III) hexaamine, we have obtained conclusive evidence for the high intrinsic EC activity of the sidewalls of the large majority of SWNTs in networks. Moreover, we show that the ends of SWNTs and the points where two SWNTs cross do not show appreciably different HET kinetics relative to the sidewall. Using finite element method modeling, we deduce standard rate constants for the two redox couples and demonstrate that HET based solely on characteristic defects in the SWNT side wall is highly unlikely. This is further confirmed by the analysis of individual line profiles taken as the SECCM probe scans over an SWNT. More generally, the studies herein demonstrate SECCM to be a powerful and versatile method for activity mapping of complex electrode materials under conditions of high mass transport, where kinetic assignments can be made with confidence.
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23
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Differential pulse techniques in weakly supported media: Changes in the kinetics and thermodynamics of electrode processes resulting from the supporting electrolyte concentration. J Electroanal Chem (Lausanne) 2012. [DOI: 10.1016/j.jelechem.2012.03.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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24
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Belding SR, Laborda E, Compton RG. Steady-state voltammetry at a microdisc electrode in the absence of excess supporting electrolyte for reversible, quasi-reversible and irreversible electrode kinetics. Phys Chem Chem Phys 2012; 14:14635-49. [DOI: 10.1039/c2cp42533e] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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25
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Batchelor-McAuley C, Dickinson EJF, Rees NV, Toghill KE, Compton RG. New Electrochemical Methods. Anal Chem 2011; 84:669-84. [DOI: 10.1021/ac2026767] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Christopher Batchelor-McAuley
- Department of Chemistry, Physical & Theoretical Chemistry Laboratory, Oxford University, South Parks Road, Oxford, OX1 3QZ, United Kingdom
| | - Edmund J. F. Dickinson
- Department of Chemistry, Physical & Theoretical Chemistry Laboratory, Oxford University, South Parks Road, Oxford, OX1 3QZ, United Kingdom
| | - Neil V. Rees
- Department of Chemistry, Physical & Theoretical Chemistry Laboratory, Oxford University, South Parks Road, Oxford, OX1 3QZ, United Kingdom
| | - Kathryn E. Toghill
- Department of Chemistry, Physical & Theoretical Chemistry Laboratory, Oxford University, South Parks Road, Oxford, OX1 3QZ, United Kingdom
| | - Richard G. Compton
- Department of Chemistry, Physical & Theoretical Chemistry Laboratory, Oxford University, South Parks Road, Oxford, OX1 3QZ, United Kingdom
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26
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Dickinson EJ, Compton RG. Influence of the diffuse double layer on steady-state voltammetry. J Electroanal Chem (Lausanne) 2011. [DOI: 10.1016/j.jelechem.2011.08.002] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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27
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Barnes EO, Belding SR, Compton RG. Electrochemical reactions where the variation of supporting electrolyte concentration is mechanistically revealing: ECE-DISP1 processes in which the chemical step is an isomerisation. J Electroanal Chem (Lausanne) 2011. [DOI: 10.1016/j.jelechem.2011.06.029] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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28
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Barnes EO, Wang Y, Limon-Petersen JG, Belding SR, Compton RG. Voltammetry in the absence of excess supporting electrolyte – ECE-DISP1 reactions: The electrochemical reduction of 2-nitrobromobenzene in acetonitrile solvent. J Electroanal Chem (Lausanne) 2011. [DOI: 10.1016/j.jelechem.2011.04.017] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Dickinson EJF, Limon-Petersen JG, Compton RG. The electroneutrality approximation in electrochemistry. J Solid State Electrochem 2011. [DOI: 10.1007/s10008-011-1323-x] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Cyclic voltammetry in weakly supported media: The reduction of the cobaltocenium cation in acetonitrile – Comparison between theory and experiment. J Electroanal Chem (Lausanne) 2010. [DOI: 10.1016/j.jelechem.2010.08.011] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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31
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Liu Y, Zhang Q, Chen S. The voltammetric responses of nanometer-sized electrodes in weakly supported electrolyte: A theoretical study. Electrochim Acta 2010. [DOI: 10.1016/j.electacta.2010.04.028] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Belding SR, Limon-Petersen JG, Dickinson EJF, Compton RG. Cyclic Voltammetry in the Absence of Excess Supporting Electrolyte Offers Extra Kinetic and Mechanistic Insights: Comproportionation of Anthraquinone and the Anthraquinone Dianion in Acetonitrile. Angew Chem Int Ed Engl 2010; 49:9242-5. [DOI: 10.1002/anie.201004874] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Belding SR, Limon-Petersen JG, Dickinson EJF, Compton RG. Cyclic Voltammetry in the Absence of Excess Supporting Electrolyte Offers Extra Kinetic and Mechanistic Insights: Comproportionation of Anthraquinone and the Anthraquinone Dianion in Acetonitrile. Angew Chem Int Ed Engl 2010. [DOI: 10.1002/ange.201004874] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Matos M, Canhoto C, Bento M, Geraldo M. Simultaneous evaluation of the dissociated and undissociated acid concentrations by square wave voltammetry using microelectrodes. J Electroanal Chem (Lausanne) 2010. [DOI: 10.1016/j.jelechem.2010.06.010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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35
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Effect of the supporting electrolytes on voltammetry at liquid/liquid microinterfaces between water and nitrobenzene, 1,2-dichloroethane or 1,6-dichlorohexane. J Electroanal Chem (Lausanne) 2009. [DOI: 10.1016/j.jelechem.2009.09.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Dumitrescu I, Unwin PR, Wilson NR, Macpherson JV. Single-Walled Carbon Nanotube Network Ultramicroelectrodes. Anal Chem 2008; 80:3598-605. [DOI: 10.1021/ac702518g] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Ioana Dumitrescu
- Departments of Chemistry and Physics, University of Warwick, Coventry, CV4 7AL, U.K
| | - Patrick R. Unwin
- Departments of Chemistry and Physics, University of Warwick, Coventry, CV4 7AL, U.K
| | - Neil R. Wilson
- Departments of Chemistry and Physics, University of Warwick, Coventry, CV4 7AL, U.K
| | - Julie V. Macpherson
- Departments of Chemistry and Physics, University of Warwick, Coventry, CV4 7AL, U.K
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CHANG J, ZEN J. A poly(dimethylsiloxane)-based electrochemical cell coupled with disposable screen printed edge band ultramicroelectrodes for use in flow injection analysis. Electrochem commun 2007. [DOI: 10.1016/j.elecom.2007.09.014] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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38
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Alteration of diffusional transport by migration and natural convection. Theoretical and direct experimental evidences upon monitoring steady-state concentration profiles at planar electrodes. J Electroanal Chem (Lausanne) 2007. [DOI: 10.1016/j.jelechem.2006.10.020] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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39
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Kanoufi F, Combellas C, Hazimeh H, Mattalia, Marchi-Delapierre C, Chanon M. Alkyl halides reactions with cathodes or with magnesium. Grignard reagent studied with radical clocks. What is the step competing with the isomerisation of the intermediate radical? J PHYS ORG CHEM 2007. [DOI: 10.1002/poc.1045] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Zhang Y, Zhang B, White HS. Electrochemistry of nanopore electrodes in low ionic strength solutions. J Phys Chem B 2006; 110:1768-74. [PMID: 16471744 DOI: 10.1021/jp054704c] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The steady-state voltammetric behavior of truncated conical nanopore electrodes (20-200 nm orifice radii) has been investigated in low ionic strength solutions. Voltammetric currents at the nanopore electrode reflect both diffusive and migrational fluxes of the redox molecule and, thus, are strongly dependent on the charge of the redox molecule and the relative concentrations of the supporting electrolyte and redox molecule. In acetonitrile solutions, the limiting current for the oxidation of the positively charged ferrocenylmethyltrimethylammonium ion is suppressed at low supporting electrolyte concentrations, while the limiting current for the oxidation of the neutral species ferrocene is unaffected by the ionic strength. The dependence of the limiting current on the relative concentrations of the supporting electrolyte and redox molecule is accurately predicted by theory previously developed for microdisk electrodes. Anomalous values of the voltammetric half-wave potential observed at very small nanopore electrodes (<50 nm radius orifice radii) are ascribed to a boundary potential between the pore interior and bulk solution (i.e., a Donnan-type potential).
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Affiliation(s)
- Yanhui Zhang
- Department of Chemistry, University of Utah, 315 South 1400 East, Salt Lake City, Utah 84112, USA
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41
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Caban K, Lewera A, Zukowska GZ, Kulesza PJ, Stojek Z, Jeffrey KR. Analysis of charge transport in gels containing polyoxometallates using methods of different sensitivity to migration. Anal Chim Acta 2006; 575:144-50. [PMID: 17723584 DOI: 10.1016/j.aca.2006.05.070] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2006] [Revised: 05/18/2006] [Accepted: 05/22/2006] [Indexed: 10/24/2022]
Abstract
Two methods have been used for examination of transport of charge in gels soaked with DMF and containing dissolved polyoxometallates. The first method is based on the analysis of both Cottrellian and steady-state currents and therefore is capable of giving the concentration of the electroactive redox centres and their transport (diffusion-type) coefficient. The second method provides the real diffusion coefficients, i.e. transport coefficients free of migrational influence, for both the substrate and the product of the electrode reaction. Several gels based on poly(methyl methacrylate), with charged (addition of 1-acrylamido-2-methyl-2-propanesulphonic acid to the polymerization mixture) and uncharged chains, have been used in the investigation. The ratio obtained for the diffusion coefficient (second method) and transport coefficient (first method) was smaller for the gels containing charged polymer chains than for the gels with uncharged chains. In part these changes could be explained by the contribution of migration to the transport of polyoxomatallates in the gels. However, the impact of the changes in the polymer-channel capacity at the electrode surface while the electrode process proceeds was also considered. These structural changes should affect differently the methods based on different time domains.
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Affiliation(s)
- Karolina Caban
- Department of Chemistry, Warsaw University, ul. Pasteura 1, 02-093 Warsaw, Poland
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42
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Nowicka A, Donten M, Palys M, Van den Bossche B, Stojek Z. Voltammetric Studies of Parallel Electrode Processes Under Low Ionic Strength Conditions. Influence of Convection. ELECTROANAL 2006. [DOI: 10.1002/elan.200503452] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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43
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Steady-state voltammetric currents of the reduction of hydrogen ions from binary acids: The effect of electrical neutrality and convection on the resistance of solution. J Electroanal Chem (Lausanne) 2006. [DOI: 10.1016/j.jelechem.2005.10.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Abstract
We consider the transport of multiple reacting species under the continuum assumption in situations such as those that frequently arise in electroanalytical chemistry. Under certain limitations, it has been shown that the total species concentration (as defined by Oldham and Feldberg) of such a system is uniform and constant. In this work, we extend the limits of the previous analysis to enable greater applicability. This is accomplished by using either of two new dependent variables, which are generalizations of the concept of total concentration. Then, conditions are determined under which the dependent variable will be uniform and constant in time. From a practical viewpoint, the described formalism allows one to simplify the multispecies transport problem formulation by eliminating one equation from the system of governing equations.
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Affiliation(s)
- Peter A Kottke
- Georgia Institute of Technology, George W. Woodruff School of Mechanical Engineering, Atlanta, Georgia 30332-0405, USA
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Szymanska J, Palys MJ, Van den Bossche B. Neutral Reagents in Solutions with Low Content of Supporting Electrolyte: How To Determine the Steady-State Conditions. Anal Chem 2004; 76:5937-44. [PMID: 15456318 DOI: 10.1021/ac049515p] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Cyclic voltammograms obtained at ultramicroelectrodes in the electrochemical systems where an uncharged reactant is significantly more concentrated than the supporting electrolyte show an unusual feature. The forward and the backward waves cross over, forming a hysteresis loop. The width of the hysteresis increases with the relative concentration of the reactant, with the electrode size, and with the scan rate. We show that the reason for this hysteresis is the slow transport of supporting electrolyte ions that are necessary to compensate the charge of the reaction product. As a result, the steady-state concentration profile of counterions is reached significantly slower than the steady-state concentration gradient of the reactant, and the counterion transport determines how rapidly the steady state for the whole system is approached. The scan rate yielding near-steady-state voltammograms can differ by more than 1 order of magnitude for systems with high and low concentrations of supporting electrolyte. Experimental evidence for this, supported by digital simulation results, is presented. The appropriate criterion for assessing the steady state in such systems is thus the identity of the forward and backward scans, without hysteresis. If this condition is not fulfilled, the formal potentials and the related parameters determined from the obtained voltammograms may be erroneous.
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Affiliation(s)
- Joanna Szymanska
- Department of Chemistry, University of Warsaw, Pasteura 1, 02-093 Warsaw, Poland
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Palys MJ, Sokolowska H, Stojek Z. Voltammetric investigation of formation of complexes in low ionic strength environments. Electrochim Acta 2004. [DOI: 10.1016/j.electacta.2003.12.054] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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48
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Goldfarb DL, Corti HR. Diffusion of Decamethylferrocene and Decamethylferrocenium Hexafluorophosphate in Supercritical Trifluoromethane. J Phys Chem B 2004. [DOI: 10.1021/jp034511u] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Affiliation(s)
- Darío L. Goldfarb
- Comisión Nacional de Energía Atómica, Unidad de Actividad Química, Av. Gral. Paz 1499 (1650) San Martín, Buenos Aires, Argentina, and Departamento de Química Inorgánica, Analítica y Química Física, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Pabellón II, Ciudad Universitaria (1428) Buenos Aires, Argentina
| | - Horacio R. Corti
- Comisión Nacional de Energía Atómica, Unidad de Actividad Química, Av. Gral. Paz 1499 (1650) San Martín, Buenos Aires, Argentina, and Departamento de Química Inorgánica, Analítica y Química Física, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Pabellón II, Ciudad Universitaria (1428) Buenos Aires, Argentina
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