Liquid metal electrode: Difference between revisions
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{{Short description|Electrode that uses a liquid metal}} |
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Liquid metal electrode is a replacement for mercury electrode variants. A few examples are those of galinstan, NaK. |
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{{Lead too short|date=July 2022}} |
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==Notes== |
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A '''liquid metal electrode''' is an [[electrode]] that uses a [[liquid metal]], such as [[mercury (element)|mercury]], [[Galinstan]], and [[NaK]].{{not verified in body|date=July 2022}} They can be used in [[electrocapillarity]], [[voltammetry]], and [[Electrical impedance|impedance]] measurements.<ref>{{cite journal |last1=Doubova |first1=L. M. |last2=De Battisti |first2=A. |last3=Fawcett |first3=W. R. |title=Adsorption of C-5 Nitriles at Liquid Metal Electrodes. A Comparison of Adsorption Parameters for Isovaleronitrile at Polarized Surfaces of Mercury and Indium–Gallium Alloy (Eutectic Composition) |journal=Langmuir |date=2003-10-01 |volume=19 |issue=22 |pages=9276–9283 |doi=10.1021/la0346447 |issn=0743-7463}}</ref> |
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==External links== |
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*[http://pubs.acs.org/doi/abs/10.1021/la0346447 American Chemical Society] |
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==Dropping mercury electrode== |
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[[File:DME 2013-11-20 19-44.jpg|thumbnail|Dropping mercury electrode]] |
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The '''dropping mercury electrode''' (DME) is a [[working electrode]] made of [[mercury (element)|mercury]] and used in [[polarography]]. Experiments run with mercury electrodes are referred to as forms of [[polarography]] even if the experiments are identical or very similar to a corresponding [[voltammetry]] experiment which uses solid working electrodes. Like other working electrodes these electrodes are used in [[electrochemical]] studies using [[potentiostat|three electrode systems]] when investigating [[electrochemical reaction mechanism|reaction mechanisms]] related to [[redox]] chemistry among other [[chemistry|chemical]] phenomena.<ref>{{Cite book |
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| edition = 2 |
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| publisher = Wiley |
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| isbn = 978-0-471-04372-0 |
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| last = Bard |
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| first = Allen J. |
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|author2=Larry R. Faulkner |
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| title = Electrochemical Methods: Fundamentals and Applications |
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| date = 2000-12-18 |
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}}</ref><ref>{{Cite book |
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| publisher = Elsevier Science |
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| isbn = 978-0-444-51958-0 |
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| last = Zoski |
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| first = Cynthia G. |
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| title = Handbook of Electrochemistry |
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| date = 2007-02-07 |
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}}</ref><ref>{{Cite book |
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| edition = 2 |
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| publisher = CRC |
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| isbn = 978-0-8247-9445-3 |
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| last = Kissinger |
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| first = Peter |
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|author2=William R. Heineman |
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| title = Laboratory Techniques in Electroanalytical Chemistry, Second Edition, Revised and Expanded |
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| date = 1996-01-23 |
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}}</ref><ref>{{Cite book |
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| edition = 5 |
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| publisher = Brooks Cole |
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| isbn = 978-0-03-002078-0 |
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| last = Skoog |
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| first = Douglas A. |author2=F. James Holler |author3=Timothy A. Nieman |
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| title = Principles of Instrumental Analysis |
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| date = 1997-09-03 |
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}}</ref><ref>{{Cite journal |
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| doi = 10.1016/0022-0728(93)02918-8 |
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| volume = 364 |
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| issue = 1–2 |
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| pages = 189–197 |
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| last = Baars |
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| first = A. |
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|author2=M. Sluyters-Rehbach |author3=J. H. Sluyters |
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| title = Application of the dropping mercury microelectrode (DMμE) in electrode kinetics and electroanalysis |
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| journal = Journal of Electroanalytical Chemistry |
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| date = January 1994 |
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}}{{dead link|date=March 2019|bot=medic}}{{cbignore|bot=medic}}</ref> |
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=== Structure === |
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A flow of [[mercury (element)|mercury]] passes through an insulating [[capillary]] producing a droplet which grows from the end of the capillary in a reproducible way. Each droplet grows until it reaches a diameter of about a millimeter and releases. The released droplet is no longer in contact with the [[working electrode]] whose contact is above the capillary. As the electrode is used mercury collects in the bottom of the cell. In some cell designs this mercury pool is connected to a lead and used as the cell's [[auxiliary electrode]]. Each released drop is immediately followed by the formation of another drop. The drops are generally produced at a rate of about 0.2 Hz. |
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=== Considerations === |
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A major advantage of the DME is that each drop has a smooth and uncontaminated surface free from any [[adsorbed]] analyte or impurity. The self-renewing electrode does not need to be cleaned or polished like a solid electrode. This advantage comes at the cost of a working electrode with a constantly changing surface area. Since the drops are produced predictably the changing surface area can be accounted for or even used advantageously. In addition, the drops' growth causes more and more addition of capacitive current to the [[faradaic current]]. These changing current effects combined with experiments where the potential is continuously changed can result in noisy traces. In some experiments the traces are continually sampled, showing all the current deviation resulting from the drop growth. Other sampling methods smooth the data by sampling the current at the electrode only once per drop at a specific size. The DME's periodic expansion into the solution and hemispherical shape also affects the way the analyte diffuses to the electrode surface. The DME consists of a fine capillary with a bore size of 20–50 [[μm]]. |
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==Hanging mercury drop electrode== |
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[[File:HangingMercuryDropElectrode.JPG|thumb|alt=Hanging Mercury Drop|Hanging mercury drop electrode]] |
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The '''hanging mercury drop electrode''' ('''HMDE''') is a [[working electrode]] variation on the dropping mercury electrode (DME). It was developed by Polish chemist [[Wiktor Kemula]].<ref>{{Cite web |url=https://www.sciencedirect.com/science/article/abs/pii/0022072862800412 |title=The hanging mercury drop electrode |website=sciencedirect.com |author=R. Narayan |access-date=13 November 2023}}</ref> Experiments run with dropping mercury electrodes are referred to as forms of [[polarography]]. If the experiments are performed at an electrode with a constant surface (like the HMDE) it is referred as [[voltammetry]]. |
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Like other working electrodes these electrodes are used in [[electrochemical]] studies using [[potentiostat|three electrode systems]] when investigating [[electrochemical reaction mechanism|reaction mechanisms]] related to [[redox]] chemistry among other [[chemistry|chemical]] phenomenon.<ref>{{Cite book | edition = 2 | publisher = Wiley | isbn = 978-0-471-04372-0 | last = Bard | first = Allen J. |author2=Larry R. Faulkner | title = Electrochemical Methods: Fundamentals and Applications | date = 2000-12-18 }}</ref><ref>{{Cite book | publisher = Elsevier Science | isbn = 978-0-444-51958-0 | last = Zoski | first = Cynthia G. | title = Handbook of Electrochemistry | date = 2007-02-07 | title-link = Handbook of Electrochemistry }}</ref><ref>{{Cite book | edition = 2 | publisher = CRC | isbn = 978-0-8247-9445-3 | last = Kissinger | first = Peter |author2=William R. Heineman | title = Laboratory Techniques in Electroanalytical Chemistry, Second Edition, Revised and Expanded | date = 1996-01-23 }}</ref><ref>{{Cite book | edition = 5 | publisher = Brooks Cole | isbn = 978-0-03-002078-0 | last = Skoog | first = Douglas A. |author2=F. James Holler |author3=Timothy A. Nieman | title = Principles of Instrumental Analysis | date = 1997-09-03 }}</ref> |
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===Distinction=== |
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The hanging mercury drop electrode produces a partial [[mercury (element)|mercury]] drop of controlled geometry and surface area at the end of a [[capillary]] in contrast to the dropping mercury electrode which steadily releases drops of mercury during an experiment. The disadvantages a DME experiences due to a constantly changing surface are not experienced by the HMDE since it has static surface area during an experiment. The static surface of the HMDE means it is more likely to suffer from the surface [[adsorption]] phenomenon than a DME. Unlike solid electrodes which need to be cleaned and polished between most experiments, the self-renewing HMDE can simply release the contaminated drop and grow a clean drop between each experiment. |
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==See also== |
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*[[Liquid rheostat]] |
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*[[Rotating disk electrode]] |
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*[[Rotating ring-disk electrode]] |
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* [[X-ray tube#Rotating anode tube|Rotating-anode X-ray tube]] |
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* [[Polarography]] |
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* [[Voltammetry]] |
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* [[Working electrode]] |
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==References== |
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<references/> |
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[[Category:Electrodes]] |
[[Category:Electrodes]] |
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Latest revision as of 04:44, 14 June 2024
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A liquid metal electrode is an electrode that uses a liquid metal, such as mercury, Galinstan, and NaK.[not verified in body] They can be used in electrocapillarity, voltammetry, and impedance measurements.[1]
Dropping mercury electrode
[edit]
The dropping mercury electrode (DME) is a working electrode made of mercury and used in polarography. Experiments run with mercury electrodes are referred to as forms of polarography even if the experiments are identical or very similar to a corresponding voltammetry experiment which uses solid working electrodes. Like other working electrodes these electrodes are used in electrochemical studies using three electrode systems when investigating reaction mechanisms related to redox chemistry among other chemical phenomena.[2][3][4][5][6]
Structure
[edit]A flow of mercury passes through an insulating capillary producing a droplet which grows from the end of the capillary in a reproducible way. Each droplet grows until it reaches a diameter of about a millimeter and releases. The released droplet is no longer in contact with the working electrode whose contact is above the capillary. As the electrode is used mercury collects in the bottom of the cell. In some cell designs this mercury pool is connected to a lead and used as the cell's auxiliary electrode. Each released drop is immediately followed by the formation of another drop. The drops are generally produced at a rate of about 0.2 Hz.
Considerations
[edit]A major advantage of the DME is that each drop has a smooth and uncontaminated surface free from any adsorbed analyte or impurity. The self-renewing electrode does not need to be cleaned or polished like a solid electrode. This advantage comes at the cost of a working electrode with a constantly changing surface area. Since the drops are produced predictably the changing surface area can be accounted for or even used advantageously. In addition, the drops' growth causes more and more addition of capacitive current to the faradaic current. These changing current effects combined with experiments where the potential is continuously changed can result in noisy traces. In some experiments the traces are continually sampled, showing all the current deviation resulting from the drop growth. Other sampling methods smooth the data by sampling the current at the electrode only once per drop at a specific size. The DME's periodic expansion into the solution and hemispherical shape also affects the way the analyte diffuses to the electrode surface. The DME consists of a fine capillary with a bore size of 20–50 μm.
Hanging mercury drop electrode
[edit]
The hanging mercury drop electrode (HMDE) is a working electrode variation on the dropping mercury electrode (DME). It was developed by Polish chemist Wiktor Kemula.[7] Experiments run with dropping mercury electrodes are referred to as forms of polarography. If the experiments are performed at an electrode with a constant surface (like the HMDE) it is referred as voltammetry.
Like other working electrodes these electrodes are used in electrochemical studies using three electrode systems when investigating reaction mechanisms related to redox chemistry among other chemical phenomenon.[8][9][10][11]
Distinction
[edit]The hanging mercury drop electrode produces a partial mercury drop of controlled geometry and surface area at the end of a capillary in contrast to the dropping mercury electrode which steadily releases drops of mercury during an experiment. The disadvantages a DME experiences due to a constantly changing surface are not experienced by the HMDE since it has static surface area during an experiment. The static surface of the HMDE means it is more likely to suffer from the surface adsorption phenomenon than a DME. Unlike solid electrodes which need to be cleaned and polished between most experiments, the self-renewing HMDE can simply release the contaminated drop and grow a clean drop between each experiment.
See also
[edit]- Liquid rheostat
- Rotating disk electrode
- Rotating ring-disk electrode
- Rotating-anode X-ray tube
- Polarography
- Voltammetry
- Working electrode
References
[edit]- ^ Doubova, L. M.; De Battisti, A.; Fawcett, W. R. (2003-10-01). "Adsorption of C-5 Nitriles at Liquid Metal Electrodes. A Comparison of Adsorption Parameters for Isovaleronitrile at Polarized Surfaces of Mercury and Indium–Gallium Alloy (Eutectic Composition)". Langmuir. 19 (22): 9276–9283. doi:10.1021/la0346447. ISSN 0743-7463.
- ^ Bard, Allen J.; Larry R. Faulkner (2000-12-18). Electrochemical Methods: Fundamentals and Applications (2 ed.). Wiley. ISBN 978-0-471-04372-0.
- ^ Zoski, Cynthia G. (2007-02-07). Handbook of Electrochemistry. Elsevier Science. ISBN 978-0-444-51958-0.
- ^ Kissinger, Peter; William R. Heineman (1996-01-23). Laboratory Techniques in Electroanalytical Chemistry, Second Edition, Revised and Expanded (2 ed.). CRC. ISBN 978-0-8247-9445-3.
- ^ Skoog, Douglas A.; F. James Holler; Timothy A. Nieman (1997-09-03). Principles of Instrumental Analysis (5 ed.). Brooks Cole. ISBN 978-0-03-002078-0.
- ^ Baars, A.; M. Sluyters-Rehbach; J. H. Sluyters (January 1994). "Application of the dropping mercury microelectrode (DMμE) in electrode kinetics and electroanalysis". Journal of Electroanalytical Chemistry. 364 (1–2): 189–197. doi:10.1016/0022-0728(93)02918-8.[dead link]
- ^ R. Narayan. "The hanging mercury drop electrode". sciencedirect.com. Retrieved 13 November 2023.
- ^ Bard, Allen J.; Larry R. Faulkner (2000-12-18). Electrochemical Methods: Fundamentals and Applications (2 ed.). Wiley. ISBN 978-0-471-04372-0.
- ^ Zoski, Cynthia G. (2007-02-07). Handbook of Electrochemistry. Elsevier Science. ISBN 978-0-444-51958-0.
- ^ Kissinger, Peter; William R. Heineman (1996-01-23). Laboratory Techniques in Electroanalytical Chemistry, Second Edition, Revised and Expanded (2 ed.). CRC. ISBN 978-0-8247-9445-3.
- ^ Skoog, Douglas A.; F. James Holler; Timothy A. Nieman (1997-09-03). Principles of Instrumental Analysis (5 ed.). Brooks Cole. ISBN 978-0-03-002078-0.