Electrochemical gas sensor, liquid electrolyte and use of a liquid electrolyte in an electrochemical gas sensor

Patent metadata

Field	Value
Publication number	US-2019101506-A1
Application number	US-201816206032-A
Country	US
Kind code	A1
Filing date	Nov 30, 2018
Priority date	Sep 9, 2013
Publication date	Apr 4, 2019
Grant date	—

Abstract

An electrochemical gas sensor ( 10 ) has a housing ( 20 ), a working electrode ( 51 ), a counterelectrode ( 52 ) and a reference electrode ( 53 ). The housing ( 20 ) has an electrolyte reservoir ( 30 ), a gas inlet orifice ( 21 ) and at least one gas outlet orifice ( 22 ). The electrolyte reservoir ( 30 ) is filled with a liquid electrolyte ( 40 ). The gas sensor ( 10 ) has a counterelectrode carrier ( 26 ). The counterelectrode ( 52 ) is suspended on the counterelectrode carrier ( 26 ) in such a way that the counterelectrode ( 52 ) is suspended in the electrolyte reservoir ( 30 ) and the electrolyte ( 40 ) flows around the counterelectrode ( 52 ) on all sides. Preferably, the electrolyte includes (I) a solvent, e.g. water, propylene carbonate, ethylene carbonate or mixtures thereof; (ii) a conductive salt, especially an ionic liquid; and/or (iii) an organic mediator, for example substituted quinones, anthraquinones, etc.

First claim

What is claimed is:

1 . A liquid electrolyte for an electrochemical gas sensor comprising a housing, a working electrode, a counterelectrode, a reference electrode, wherein the housing has an electrolyte reservoir, a gas inlet opening and at least one gas outlet opening, a liquid electrolyte in the electrolyte reservoir and a counterelectrode carrier, the counterelectrode being suspended on the counterelectrode carrier such that the counterelectrode is suspended in the electrolyte reservoir and the electrolyte flows around the counterelectrode on all sides, wherein the electrolyte contains at least one conductive salt, a solvent and an organic mediator, wherein the electrolyte contains, furthermore, a buffer, said buffer being a compound according to
R 1 —(CR 2 R 3 ) n —SO 3 H,   (I)

in which one of:
n=1, 2, 3, 4 or 5, preferably n=2 or n=3, wherein R 2 and R 3 are selected, independently from one another, from among H, NH and OH, and wherein R 1 is selected from the group containing piperazinyl, substituted piperazinyl, N-morpholino, cycloalkyl, tris-(hydroxyalkyl)alkyl; and
n=2 or n=3, wherein all R 2 and R 3 are selected, independently from one another, from among H, NH and OH, and wherein R 1 is selected from the group containing [4-(2-hydroxyethyl)-1]-piperazinyl, (N-morpholino)-, N-cyclohexyl-, tris-(hydroxymethyl)methyl, wherein the conductive salt contains an ionic liquid and wherein the solvent is selected from among water, propylene carbonate, ethylene carbonate or mixtures thereof.

2 . An electrolyte according to claim 1 , wherein the organic mediator is selected from the group containing ortho-quinones, para-quinones, substituted ortho-quinones and substituted para-quinones, dihydroxynaphthalene, substituted dihydroxynaphthalene, anthraquinone, and substituted anthraquinone, 1,2-dihydroxybenzene, 1,4-dihydroxybenzene, 1,4-naphthodihydroxybenzene, substituted 1,2-dihydroxybenzene, substituted 1,4-dihydroxybenzene, and substituted 1,4-naphthodihydroxybenzene, substituted anthraquinone, substituted 1,2-dihydroxybenzene, and substituted 1,4-dihydroxybenzene, wherein the substituents of the substituted anthraquinones, substituted 1,2-dihydroxybenzene and/or substituted 1,4-hydroquinone are selected from the group containing sulfonyl, tert.-butyl, hydroxyl, alkyl, aryl, preferably sulfonic acid, and tert.-butyl.

3 . An electrolyte according to claim 1 , wherein the buffer is 3-(N-morpholino)-propanesulfonic acid.

4 . An electrochemical gas sensor method comprising the steps of:
providing an electrochemical gas sensor comprising a housing, a working electrode, a counterelectrode, a reference electrode, wherein the housing has an electrolyte reservoir, a gas inlet opening and at least one gas outlet opening and a counterelectrode carrier, the counterelectrode being suspended on the counterelectrode carrier such that the counterelectrode is suspended in the electrolyte reservoir; and providing a liquid electrolyte in the electrolyte reservoir, wherein the electrolyte contains at least one conductive salt, a solvent and an organic mediator and the electrolyte flows around the counterelectrode on all sides.

5 . An electrochemical gas sensor method according to claim 4 , further comprising detecting NH 3 or NH 3 -containing gas mixtures with the electrochemical gas sensor with the provided liquid electrolyte.

6 . An electrochemical gas sensor method according to claim 4 , wherein the electrolyte contains a buffer comprised of a compound according to
R 1 —(CR 2 R 3 ) n —SO 3 H,   (I)

in which one of:
n=1, 2, 3, 4 or 5, preferably n=2 or n=3, wherein R 2 and R 3 are selected, independently from one another, from among H, NH and OH, and wherein R 1 is selected from the group containing piperazinyl, substituted piperazinyl, N-morpholino, cycloalkyl, tris-(hydroxyalkyl)alkyl; and
n=2 or n=3, wherein all R 2 and R 3 are selected, independently from one another, from among H, NH and OH, and wherein R 1 is selected from the group containing [4-(2-hydroxyethyl)-1]-piperazinyl, (N-morpholino)-, N-cyclohexyl-, tris-(hydroxymethyl)methyl, wherein the conductive salt contains an ionic liquid and wherein the solvent is selected from among water, propylene carbonate, ethylene carbonate or mixtures thereof.

7 . An electrochemical gas sensor method according to claim 4 , wherein the electrochemical gas sensor comprises a separating element, the counterelectrode carrier comprising a radial spoke extending between the separating element and the housing, the counterelectrode being suspended on the radial spoke such that the counterelectrode is suspended in the electrolyte reservoir and the electrolyte flows around the counterelectrode on all sides of the counterelectrode.

8 . An electrochemical sensor comprising:
a housing; a working electrode; a counterelectrode; a reference electrode, wherein the housing has an electrolyte reservoir, a gas inlet opening and at least one gas outlet opening; a liquid electrolyte in the electrolyte reservoir; and a counterelectrode carrier, the counterelectrode being suspended on the counterelectrode carrier such that the counterelectrode is suspended in the electrolyte reservoir and the electrolyte flows around the counterelectrode on all sides, wherein the electrolyte contains at least one conductive salt, a solvent and an organic mediator, wherein the electrolyte contains, furthermore, a buffer, said buffer being a compound according to
R 1 —(CR 2 R 3 ) n —SO 3 H,   (I)

in which one of:
n=1, 2, 3, 4 or 5, preferably n=2 or n=3, wherein R 2 and R 3 are selected, independently from one another, from among H, NH and OH, and wherein R 1 is selected from the group containing piperazinyl, substituted piperazinyl, N-morpholino, cycloalkyl, tris-(hydroxyalkyl)alkyl; and
n=2 or n=3, wherein all R 2 and R 3 are selected, independently from one another, from among H, NH and OH, and wherein R 1 is selected from the group containing [4-(2-hydroxyethyl)-1]-piperazinyl, (N-morpholino)-, N-cyclohexyl-, tris-(hydroxymethyl)methyl, wherein the conductive salt contains an ionic liquid and wherein the solvent is selected from among water, propylene carbonate, ethylene carbonate or mixtures thereof.

9 . An electrochemical sensor according to claim 8 , wherein the organic mediator is selected from the group containing ortho-quinones, para-quinones, substituted ortho-quinones and substituted para-quinones, dihydroxynaphthalene, substituted dihydroxynaphthalene, anthraquinone, and substituted anthraquinone, 1,2-dihydroxybenzene, 1,4-dihydroxybenzene, 1,4-naphthodihydroxybenzene, substituted 1,2-dihydroxybenzene, substituted 1,4-dihydroxybenzene, and substituted 1,4-naphthodihydroxybenzene, substituted anthraquinone, substituted 1,2-dihydroxybenzene, and substituted 1,4-dihydroxybenzene, wherein the substituents of the substituted anthraquinones, substituted 1,2-dihydroxybenzene and/or substituted 1,4-hydroquinone are selected from the group containing sulfonyl, tert.-butyl, hydroxyl, alkyl, aryl, preferably sulfonic acid, and tert.-butyl.

10 . An electrochemical sensor according to claim 8 , wherein the buffer is 3-(N-morpholino)-propanesulfonic acid.

11 . An electrochemical sensor according to claim 8 , further comprising:
a separating element, the counterelectrode carrier comprising a radial spoke extending between the separating element and the housing, the counterelectrode being suspended on the radial spoke such that the counterelectrode is suspended in the electrolyte reservoir and the electrolyte flows around the counterelectrode on all sides.

12 . An electrochemical sensor according to claim

Assignees

• Draeger Safety Ag & Co Kgaa

Inventors

• Nauber Andreas
• Sick Michael
• Steiner Gregor
• Mattern-Frühwald Marie-Isabell
• Mett Frank
• Chrzan Rigobert
• Sommer Sabrina

Classifications

• G01N27/413

  Concentration cells using liquid electrolytes {measuring currents or voltages in voltaic cells} · CPC title

• Y02A50/246

  Cross-Sectional Technologies · mapped topic

• G01N33/0054

  Ammonia · CPC title

• G01N27/4045 Primary

  for gases other than oxygen · CPC title

• H01M2300/0011

  Sulfuric acid-based · CPC title