GB2215844A - Silver/silver chloride electrodes - Google Patents
Silver/silver chloride electrodes Download PDFInfo
- Publication number
- GB2215844A GB2215844A GB8806687A GB8806687A GB2215844A GB 2215844 A GB2215844 A GB 2215844A GB 8806687 A GB8806687 A GB 8806687A GB 8806687 A GB8806687 A GB 8806687A GB 2215844 A GB2215844 A GB 2215844A
- Authority
- GB
- United Kingdom
- Prior art keywords
- silver
- particles
- chloride
- silver chloride
- electrode
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
- 239000004332 silver Substances 0.000 title claims abstract description 60
- 229910021607 Silver chloride Inorganic materials 0.000 title claims abstract description 54
- HKZLPVFGJNLROG-UHFFFAOYSA-M silver monochloride Chemical compound [Cl-].[Ag+] HKZLPVFGJNLROG-UHFFFAOYSA-M 0.000 title claims abstract description 50
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 claims abstract description 61
- 229910052709 silver Inorganic materials 0.000 claims abstract description 56
- 239000002245 particle Substances 0.000 claims abstract description 32
- 239000000243 solution Substances 0.000 claims abstract description 17
- SQGYOTSLMSWVJD-UHFFFAOYSA-N silver(1+) nitrate Chemical compound [Ag+].[O-]N(=O)=O SQGYOTSLMSWVJD-UHFFFAOYSA-N 0.000 claims abstract description 15
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 claims abstract description 14
- 239000000725 suspension Substances 0.000 claims abstract description 14
- 239000000758 substrate Substances 0.000 claims abstract description 8
- 239000011780 sodium chloride Substances 0.000 claims abstract description 7
- 239000012266 salt solution Substances 0.000 claims abstract description 6
- 238000013019 agitation Methods 0.000 claims abstract description 5
- GGCZERPQGJTIQP-UHFFFAOYSA-N sodium;9,10-dioxoanthracene-2-sulfonic acid Chemical compound [Na+].C1=CC=C2C(=O)C3=CC(S(=O)(=O)O)=CC=C3C(=O)C2=C1 GGCZERPQGJTIQP-UHFFFAOYSA-N 0.000 claims abstract description 5
- 229910001961 silver nitrate Inorganic materials 0.000 claims abstract description 4
- 238000007650 screen-printing Methods 0.000 claims abstract description 3
- 238000001125 extrusion Methods 0.000 claims abstract 2
- 238000000034 method Methods 0.000 claims description 22
- 239000011230 binding agent Substances 0.000 claims description 5
- 238000001035 drying Methods 0.000 claims description 5
- 238000000151 deposition Methods 0.000 claims description 2
- 239000007788 liquid Substances 0.000 claims description 2
- 238000001556 precipitation Methods 0.000 claims description 2
- 150000003841 chloride salts Chemical class 0.000 claims 1
- 239000010410 layer Substances 0.000 claims 1
- 230000000063 preceeding effect Effects 0.000 claims 1
- 239000002344 surface layer Substances 0.000 claims 1
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 abstract description 2
- 238000000576 coating method Methods 0.000 abstract description 2
- 239000011248 coating agent Substances 0.000 abstract 1
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 5
- 238000004519 manufacturing process Methods 0.000 description 4
- 238000003756 stirring Methods 0.000 description 4
- 229910001220 stainless steel Inorganic materials 0.000 description 3
- 239000010935 stainless steel Substances 0.000 description 3
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 2
- 239000008367 deionised water Substances 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- 239000000843 powder Substances 0.000 description 2
- 238000002360 preparation method Methods 0.000 description 2
- NDVLTYZPCACLMA-UHFFFAOYSA-N silver oxide Chemical compound [O-2].[Ag+].[Ag+] NDVLTYZPCACLMA-UHFFFAOYSA-N 0.000 description 2
- 238000005406 washing Methods 0.000 description 2
- 102000004190 Enzymes Human genes 0.000 description 1
- 108090000790 Enzymes Proteins 0.000 description 1
- WQZGKKKJIJFFOK-GASJEMHNSA-N Glucose Natural products OC[C@H]1OC(O)[C@H](O)[C@@H](O)[C@@H]1O WQZGKKKJIJFFOK-GASJEMHNSA-N 0.000 description 1
- 244000090125 Solidago odora Species 0.000 description 1
- 238000005056 compaction Methods 0.000 description 1
- 230000008021 deposition Effects 0.000 description 1
- ZOMNIUBKTOKEHS-UHFFFAOYSA-L dimercury dichloride Chemical class Cl[Hg][Hg]Cl ZOMNIUBKTOKEHS-UHFFFAOYSA-L 0.000 description 1
- 235000012489 doughnuts Nutrition 0.000 description 1
- 238000005868 electrolysis reaction Methods 0.000 description 1
- 239000008103 glucose Substances 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 229910052697 platinum Inorganic materials 0.000 description 1
- 239000002244 precipitate Substances 0.000 description 1
- 239000000047 product Substances 0.000 description 1
- 229940098221 silver cyanide Drugs 0.000 description 1
- LFAGQMCIGQNPJG-UHFFFAOYSA-N silver cyanide Chemical compound [Ag+].N#[C-] LFAGQMCIGQNPJG-UHFFFAOYSA-N 0.000 description 1
- 229910001923 silver oxide Inorganic materials 0.000 description 1
- 239000012086 standard solution Substances 0.000 description 1
- 239000007858 starting material Substances 0.000 description 1
- 239000011550 stock solution Substances 0.000 description 1
- 239000004094 surface-active agent Substances 0.000 description 1
- 238000005979 thermal decomposition reaction Methods 0.000 description 1
- 238000009736 wetting Methods 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
- G01N27/26—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating electrochemical variables; by using electrolysis or electrophoresis
- G01N27/28—Electrolytic cell components
- G01N27/30—Electrodes, e.g. test electrodes; Half-cells
- G01N27/301—Reference electrodes
Landscapes
- Chemical & Material Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Health & Medical Sciences (AREA)
- Physics & Mathematics (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- Molecular Biology (AREA)
- Analytical Chemistry (AREA)
- Biochemistry (AREA)
- General Health & Medical Sciences (AREA)
- General Physics & Mathematics (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Powder Metallurgy (AREA)
Abstract
Silver/silver chloride electrodes are prepared by suspending finely divided silver particles in an aqueous chloride solution, e.g. NaCl, by vigorous agitation, and adding a silver salt solution, e.g. aqueous silver nitrate, slowly to the suspension to precipitate silver chloride as a surface coating on the suspended silver particles. The silver chloride coated silver particles are recovered and formed into an electrode, for example by extrusion, compacting in a tabletting press, or screen printing onto a suitable substrate, e.g. a silver strip. The size of the silver particles is preferably in the range 0.5-150 mu m.
Description
SILVER/SILVER CHLORIDE ELECTRODES
This invention relates to silver/silver chloride electrodes. Silver and silver chloride electrodes are extensively used in electrochemical applications, and particularly as reference electrodes for the measurement of electrode potentials.
Prior art methods for the preparation of silver/silver chloride reference electrodes involve the deposition of finely divided silver on a platinum support, e.g. an electrolytically silver-plated platinum wire or helix, by the thermal decomposition of a silver oxide paste applied to the wire in one or more coatings, and followed by electrolytic chloridisation, either in aqueous hydrochloric acid or dilute sodium chloride solution and in which thc silver coated platinum wire is immersed as the anode, under low current conditions, thereby to form a surface film of silver chloride on the electrode.
Alternatively a fully electrolytic method can be used in which the finely divided silver is initially deposited on the platinum wire by electrolysis in a solution of silver cyanide.
According to this invention, a method has been devised for the manufacture of silver/silver chloride electrodes which are of improved stability, reliability and ease of manufacture.
According to this method, silver/silver chloride electrodes are prepared by suspending finely divided silver, preferably having a particle size in the range 0.5 to 150 lim, more preferably from 0.5 to 50 Fm, and most preferably from 0.75 to 25 lim, by vigorous agitation in an aqueous chloride solution, preferably sodium chloride, adding aqueous silver nitrate or other water-soluble silver salt solution, slowly to the suspension whilst maintaining conditions of agitation to keep the silver particles in suspension thereby to act as nucleating sites for the resultant precipitation of silver chloride from solution, recovering the silver chloride coated silver particles from the suspension, and forming the silver chloride coated silver particles into an electrode, preferably after washing and drying the precipitated particles.
Conditions for forming the silver chloride precipitate are not critical.
Preferably this is done at room temperature using for example a 4M solution of sodium chloride and a 5M solution of silver nitrate, which is added slowly to the agitated silver suspension, e.g. dropwise at a rate of from 1 to 25 ml per minute.
In one method of forming the electrode, the precipitated silver chloride coated silver particles, after washing and drying are compacted, with or without a binder to form a high density compact of silver/silver chloride particles, e.g. in tablet form or anr other suitable compacted shape, e.g. rod or wire. Such compacting may be done in a suitable press, or alternatively the particles may be extruded into a rod, for example, by suspension in a suitable vehicle to form a paste, with or without a binder, which is then extruded to form a silver/silver chloride extrudate, followed by drying of the extrudate. Other suitable method for forming the precipitated silver/silver chloride particles into a form suitable for use as a reference electrode will be apparent to persons skilled in the art.
In an alternative method, the silver/silver chloride reference electrodes can be formed by suspending the precipitated silver/silver chloride particles in a liquid vehicle, with or without a suitable binder, to fnrm an "ink" comprising the silver/silver chloride particles in suspension, and applying the suspension to the surface of a suitable substrate, e.g. by screen printing, preferably to an electrically conductive substrate such as a silver strip, and drying the coated substrate to deposit thereon a thin layer of the silver/silver chloride particles.
The individual silver particles preferably have a silver:silver chloride weight ratio in the range 5:1 to 1:10, more susually from 1:1 to 1:5.
The preparation and properties of silver/silver chloride electrodes prepared according to this invention are illustrated by the following example.
EXAMPLE
General preparative technique:
Solution A 1. Make up a stock solution of 4.1 mol dm-3 sodium chloride.
2. Put silver powder in an appropriate volume of stock sodium chloride solution (see Table
bel(oRwF asnd stir vigorously. 3. Add 0.2% v/v of Triton^X100 surfactant (to improve wetting ot the
silver).
4. Allow to stir for 2 minutes to ensure thorough mixing.
Solution B 1. Make up a standard solution of 75yob saturated silver nitrate (91.5 g
AgNO3 made up to 108 ml with de-ionised water).
Procedure 1. Using a burette, add dropwise the appropriate volume of solution B to
solution A (at a rate of approximately one drop/second), stirring
vigorously all the while. After all of solution B has been added, allow
the silver/silver chloride suspension to continue stirring for a further
10 minutes.
2. Filter, and wash silver/silver chloride with a tota! of 750 ml of de
ionised water via a wash bottle.
3. Dry in an oven at 1500C for 12 to 24 hours and store desiccated.
Masses of Starting Materials for Fabrication of Reference Electrodes
(for given molar ratios of Ag metal to AgCl)
with a total product mass of 25 g
Molar Solution A Solution B Final Final
Ratio Mass NaCI AgNO3/g Mass Ag:AgCl
Ag/AgCl Ag/g Mass/g Vol/ml Mass/g Vol/mlAgCl/g wt. ratio 10:5.0 15.0191 32.5472 139.2 11.8273 12.9 9.9817 1.5:1 10:7.5 12.5199 27.1313 116.1 14.7877 16.2 12.4801 1:1 10:10 10.7338 23.2607 99.5 16.9040 18.5 14.2662 1:1.33 7.5:10 9.0185 19.5436 83.6 18.9367 20.7 15.9817 1:1.77 5.0:10 6.8341 14.8099 63.4 21.5250 23.5 18.1661 1:2.66
Electrode Fabrication
Silver/silver chloride powders prepared as above have been fabricated into compacted silver/silver chloride electrodes as follows: approximately 1 g quantities of the silver/silver chloride are placed in a stainless steel tabletting press consisting of a blind stainless steel cylinder approximately 5 mm internal diameter with a close fitting stainless steel piston. The powder is compacted by placing the press in a laboratory bench vice and tightening the vice manually. Following compaction, the compact silver/silver chloride tablet is recovered ready for use as a reference electrode. As well as tabletted electrodes in disc form, other compacted shapes have been constructed, e.g. doughnut or ring-shaped electrodes.
The tabletted silver/silver chloride reference electrodes made from the coated silver particles as described above are especially suitable as thc reference/counter electrode in a 2-electrode cell configuraticn, e.g. modified Clark cells of the type described in EP-A-0 247 850. Whereas electrochemically-chlorided silver functions as a reference/counter electrode in such cells for approximately 100 to 250 measurements using a glucose enzyme electrode (Figure 16 of EP-A-0 247 850), electrode of the present invention are found to be still usable after as many as 8,000 readings.
When compared with a saturated calomel electrode, the potential of compacted silver/silver chloride electrodes made according to the present invention is found to drift by less than 2 mV over 24 hours.
Claims (13)
1. A method of preparing a silver/silver chloride electrode, which comprises suspending finely divided particles of silver by vigorous agitation in an aqueous chloride salt solution, slowly adding an aqueous silver salt solution to the suspension with continued agitation to keep the silver particles in suspension and thereby to act as nucleating sites for the resultant precipitation of silver chloride from solution, recovering the silver chloride coated silver particles and forming the recovered silver chloride coated silver particles to form the electrodc.
2. A method according to claim 1, wherein the silver particles in suspension have a particle size in the range 0.5 to 150 lim.
3. A method according to claim 2, wherein said particle size is in the range 0.75 to 25 ,um.
4. A method according to claim 1, 2 or 3, wherein said silver salt solution is aqueous sodium chloride.
5. A method according to claim 1, 2, 3 or 4, wherein said silver salt solution is aqueous silver nitrate solution.
6. A method according to any one of claims 1 to 5, wherein the silver/silver chloride particles are formed into an electrode by compressing the particles, with or without a binder, to form a compacted silver/silver chloride electrode.
7. A method according to claim 6, wherein the silver/silver chloride particles are compacted in a press to form a silver/silver chloride electrode in compacted tablet form.
8. A method according to claim 6, wherein the silver/silver chloride particles are compacted by extrusion through a die, to form a compacted silver/silver chloride electrode in extruded form.
9. A method according to any one of claims 1 to 5, wherein the silver/silver chloride particles are suspended in a liquid vehicle, with or without an additional binder, to form a suspension, depositing the suspension as a surface layer on a substrate, and drying to form an electrically conductive layer of silver/silver chloride particles on thc surface of said substrate.
10. A method according to claim 9, wherein the substrate is electrically conductive.
11. A method according to claim 10, wherein the substrate is a silver strip.
12. A method according to any one of claims 9 to 12, wherein the silver/silver chloride particles are deposited onto said surface by screen printing.
13. A silver/silver chloride reference electrode when prepared by a method claimed in any one of the preceeding claims.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB8806687A GB2215844A (en) | 1988-03-21 | 1988-03-21 | Silver/silver chloride electrodes |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB8806687A GB2215844A (en) | 1988-03-21 | 1988-03-21 | Silver/silver chloride electrodes |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB8806687D0 GB8806687D0 (en) | 1988-04-20 |
| GB2215844A true GB2215844A (en) | 1989-09-27 |
Family
ID=10633803
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB8806687A Withdrawn GB2215844A (en) | 1988-03-21 | 1988-03-21 | Silver/silver chloride electrodes |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2215844A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0455072A1 (en) * | 1990-05-02 | 1991-11-06 | Pacesetter AB | Silver chloride reference electrode |
| EP4442777A1 (en) * | 2023-04-04 | 2024-10-09 | Henkel AG & Co. KGaA | Electrically conductive ink composition |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113845180B (en) * | 2021-06-02 | 2023-12-29 | 哈尔滨工业大学（深圳） | Silver carbon electrode material and its preparation method and application |
| CN116145167B (en) * | 2022-11-29 | 2025-09-26 | 大连大学 | Preparation method and application of polyvinyl alcohol hydrogel-carbon foam-silver/silver chloride reference electrode |
-
1988
- 1988-03-21 GB GB8806687A patent/GB2215844A/en not_active Withdrawn
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0455072A1 (en) * | 1990-05-02 | 1991-11-06 | Pacesetter AB | Silver chloride reference electrode |
| US5230786A (en) * | 1990-05-02 | 1993-07-27 | Siemens Aktiengesellschaft | Silver-chloride reference electrode |
| EP4442777A1 (en) * | 2023-04-04 | 2024-10-09 | Henkel AG & Co. KGaA | Electrically conductive ink composition |
| WO2024208505A1 (en) * | 2023-04-04 | 2024-10-10 | Henkel Ag & Co. Kgaa | Electrically conductive ink composition |
Also Published As
| Publication number | Publication date |
|---|---|
| GB8806687D0 (en) | 1988-04-20 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |