Electrochemical gas sensor and electrolyte for an electrochemical gas sensor

Abstract

An electrochemical gas sensor ( 10 ) includes a housing ( 20 ) and with at least one electrode ( 21, 22 ). The housing ( 20 ) has a gas inlet ( 23 ). An at least strongly acidic, liquid electrolyte ( 30 ) is present in the gas sensor ( 10 ). The electrolyte ( 30 ) partly wets the electrode ( 21, 22 ). Provisions are made in such a gas sensor ( 10 ) for the electrolyte ( 30 ) to contain an additive that contains at least one surfactant. An electrolyte ( 30 ) is also provided for a gas sensor ( 10 ), which electrolyte ( 30 ) contains at least one surfactant as an additive.

1 .- 35 . (canceled) 
     
     
         36 . An electrochemical gas sensor comprising:
 a housing comprising a gas inlet;   at least two electrodes;   a wick system; and   an acidic, liquid electrolyte, wherein the electrolyte is in contact with the wick system and partly wets the at least two electrodes, the electrolyte comprising an additive having at least one surfactant, and an acid selected from the group consisting of sulfuric acid, perchloric acid, sulfurous acid, hydrochloric acid, nitric acid, nitrous acid, phosphoric acid and a mixture of at least two of sulfuric acid, perchloric acid, sulfurous acid, hydrochloric acid, nitric acid, nitrous acid, phosphoric acid, and combinations thereof.   
     
     
         37 . The electrochemical gas sensor of  claim 36 , wherein the additive consists entirely of the surfactant. 
     
     
         38 . The electrochemical gas sensor of  claim 36 , wherein the additive comprises a plurality of components, wherein at least one other of the plurality of components comprises the at least one surfactant. 
     
     
         39 . The electrochemical gas sensor of  claim 36 , wherein the additive comprises halogenated and halogen-free surfactants. 
     
     
         40 . The electrochemical gas sensor of  claim 36 , wherein the at least one surfactant comprises a counterion selected from the group consisting of heterocyclic cations, ammonium ions, H± ion, alkali or alkaline earth ions, HSO 4   −  ions, H 2 PO 4   −  ions, CF 3 —SO 3   −  ions, C 2 F 4 HSO 3   −  ions, CF 3 —COO −  ions, and (F 3 C—SO 2 ) 2 N −  ions, and combinations thereof. 
     
     
         41 . The electrochemical gas sensor of  claim 40 , wherein each of the at least one surfactant comprises the same counterion. 
     
     
         42 . The electrochemical gas sensor of  claim 36 , wherein the at least one surfactant comprises an anionic surfactant. 
     
     
         43 . The electrochemical gas sensor of  claim 36 , wherein the at least one surfactant comprises an alkyl sulfonate. 
     
     
         44 . The electrochemical gas sensor of  claim 43 , wherein the alkyl chain of the alkyl sulfonate comprises at least 1 and no more than 18 carbon atoms. 
     
     
         45 . The electrochemical gas sensor of  claim 36 , wherein the at least one surfactant comprises a counterion, selected from the group consisting of heterocyclic cations, H +  ions, Na +  ions, K +  ions, Li +  ions, ((C s H 2s+1 )(C p H 2p+1 )(C q H 2q+1 )(C r H 2r+1 ))N +  ions, in which S={0, 1, 2, 3, 4, 5, 6}, p={0, 1, 2, 3, 4, 5, 6}, q={0, 1, 2, 3, 4, 5, 6}, and r={0, 1, 2, 3, 4, 5, 6}, and combinations thereof. 
     
     
         46 . The electrochemical gas sensor of  claim 36 , wherein the at least one surfactant is a halogen-free anionic surfactant corresponding to: (C n H 2+1 —SO 3 )R1 in which n={1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12}, R1 is selected from the group consisting of H + , Na + , K + , Li + , ((C s H 2s+1 )(C p H 2p+1 )(C q H 2q+1 )(C r H 2r+1 ))N + , in which s={0, 1, 2, 3, 4, 5, 6}, p={0, 1, 2, 3, 4, 5, 6}, q={0, 1, 2, 3, 4, 5, 6}, and r={0, 1, 2, 3, 4, 5, 6), and combinations thereof. 
     
     
         47 . The electrochemical gas sensor of  claim 36 , wherein the at least one surfactant is selected from the group consisting of sodium 1-butane sulfonate, sodium 1-pentane sulfonate, sodium 1-hexane sulfonate, sodium 1-heptane sulfonate, sodium 1-octane sulfonate, sodium 1-nonane sulfonate, sodium 1-decane sulfonate, sodium 1-undecane sulfonate, sodium 1-dodecane sulfonate, sodium isobutyl sulfonate, sodium isopentyl sulfonate, sodium isohexyl sulfonate, sodium isoheptyl sulfonate, sodium isooctyl sulfonate, sodium isononyl sulfonate, sodium isodecyl sulfonate, sodium isoundecyl sulfonate, sodium isododecyl sulfonate, potassium 1-butane sulfonate, potassium 1-pentane sulfonate, potassium 1-hexane sulfonate, potassium 1-heptane sulfonate, potassium 1-octane sulfonate, potassium 1-nonane sulfonate, potassium 1-decane sulfonate, potassium 1-undecane sulfonate, potassium 1-dodecane sulfonate, potassium isobutyl sulfonate, potassium isopentyl sulfonate, potassium isohexyl sulfonate, potassium isoheptyl sulfonate, potassium isooctyl sulfonate, potassium isononyl sulfonate, potassium isodecyl sulfonate, potassium isoundecyl sulfonate, potassium isododecyl sulfonate, and combinations thereof. 
     
     
         48 . The electrochemical gas sensor of  claim 36 , wherein the at least one surfactant is an alkyl benzene sulfonate, an alkyl sulfate or an alkyl ether sulfate. 
     
     
         49 . The electrochemical gas sensor of  claim 36 , wherein the at least one surfactant is a cationic surfactant. 
     
     
         50 . The electrochemical gas sensor of  claim 49 , wherein the cationic surfactant is an ammonium compound. 
     
     
         51 . The electrochemical gas sensor of  claim 36 , wherein the at least one surfactant is a surfactant corresponding to:
   [((C s H 2s+1 )(C p H 2p+1 )(C q H 2q+1 )(C r H 2r+1 ))N + ]R2   
       in which
 s={0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20}, 
 p={0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20}, 
 q={0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20}, and 
 r={0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20}, 
 wherein R2 is selected from the group consisting of HSO 4   − , H 2 PO 4   − , CF 3 —SO 3   − , C 2 F 2 HSO 3   − , CF 3 —COO − , (CF 3 —SO 2 ) 2 N −  and combinations thereof. 
 
     
     
         52 . The electrochemical gas sensor of  claim 50 , wherein the ammonium compound comprises at least two alkyl groups, wherein each of the at least two alkyl groups are independently selected from alkyl groups comprising linear carbon chains of at least 1 and no more than 18 carbon atoms. 
     
     
         53 . The electrochemical gas sensor of  claim 36 , wherein the at least one surfactant comprises a concentration ranging from 0.01 mmol/L to 2 mol/L. 
     
     
         54 . The electrochemical gas sensor of  claim 36 , wherein each of the at least two electrodes, the electrolyte, and a gas to be analyzed define a three-phase boundary. 
     
     
         55 . The electrochemical gas sensor of  claim 36 , wherein the at least one surfactant is selected from the group consisting of sodium 1-butane sulfonate, sodium 1-dodecyl sulfonate, sodium 1-isobutyl sulfonate, sodium 1-isododecyl sulfonate, potassium 1-butane sulfonate, potassium 1-dodecyl sulfonate, potassium 1-isobutyl sulfonate, potassium 1-isododecyl sulfonate, sodium 1-butane sulfonate, sodium 1-dodecyl sulfonate, potassium 1-butane sulfonate, potassium 1-dodecyl sulfonate, corresponding lithium, ammonium, di-, tri- or tetraalkylammonium compounds of all the foregoing compounds, and combinations thereof. 
     
     
         56 . The electrochemical gas sensor of  claim 36 , wherein the surfactant is selected from the group consisting of a polyfluoro-alkyl-sulfonic acid comprising from 6 to 15 fluorine atoms and a polyfluorooctyl sulfonate with a counterion that is selected from the group consisting of H+ ions, Na+ ions, K+ ions, Li+ ions, tetraalkylammonium ions, trialkylammonium ions, dialkylammonium ions, and combinations thereof.