JPH0334690Y2 - - Google Patents
Info
- Publication number
- JPH0334690Y2 JPH0334690Y2 JP8701083U JP8701083U JPH0334690Y2 JP H0334690 Y2 JPH0334690 Y2 JP H0334690Y2 JP 8701083 U JP8701083 U JP 8701083U JP 8701083 U JP8701083 U JP 8701083U JP H0334690 Y2 JPH0334690 Y2 JP H0334690Y2
- Authority
- JP
- Japan
- Prior art keywords
- gas
- electrode
- oxygen
- permeable membrane
- counter 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.)
- Expired
Links
- 239000007789 gas Substances 0.000 claims description 45
- 239000012528 membrane Substances 0.000 claims description 27
- 239000001301 oxygen Substances 0.000 claims description 23
- 229910052760 oxygen Inorganic materials 0.000 claims description 23
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 22
- 238000001514 detection method Methods 0.000 claims description 13
- 239000003792 electrolyte Substances 0.000 claims description 6
- 229910052751 metal Inorganic materials 0.000 claims description 6
- 239000002184 metal Substances 0.000 claims description 6
- 238000000151 deposition Methods 0.000 claims description 3
- 239000008151 electrolyte solution Substances 0.000 claims description 2
- 230000005518 electrochemistry Effects 0.000 claims 1
- 229910044991 metal oxide Inorganic materials 0.000 claims 1
- 150000004706 metal oxides Chemical class 0.000 claims 1
- 238000005259 measurement Methods 0.000 description 10
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 6
- 238000006722 reduction reaction Methods 0.000 description 6
- 229910052737 gold Inorganic materials 0.000 description 4
- 239000010931 gold Substances 0.000 description 4
- 238000000034 method Methods 0.000 description 4
- 239000012466 permeate Substances 0.000 description 4
- 238000006479 redox reaction Methods 0.000 description 4
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 description 3
- 230000002159 abnormal effect Effects 0.000 description 3
- 229910002091 carbon monoxide Inorganic materials 0.000 description 3
- 238000006243 chemical reaction Methods 0.000 description 3
- 238000010586 diagram Methods 0.000 description 3
- 238000007254 oxidation reaction Methods 0.000 description 3
- 229910052697 platinum Inorganic materials 0.000 description 3
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 description 2
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 description 2
- 229910052741 iridium Inorganic materials 0.000 description 2
- 229910052742 iron Inorganic materials 0.000 description 2
- 150000002739 metals Chemical class 0.000 description 2
- 229910052763 palladium Inorganic materials 0.000 description 2
- 238000011176 pooling Methods 0.000 description 2
- 229910052703 rhodium Inorganic materials 0.000 description 2
- 229910052709 silver Inorganic materials 0.000 description 2
- 239000004332 silver Substances 0.000 description 2
- 239000002341 toxic gas Substances 0.000 description 2
- RWSOTUBLDIXVET-UHFFFAOYSA-N Dihydrogen sulfide Chemical compound S RWSOTUBLDIXVET-UHFFFAOYSA-N 0.000 description 1
- PIYVNGWKHNMMAU-UHFFFAOYSA-N [O].O Chemical compound [O].O PIYVNGWKHNMMAU-UHFFFAOYSA-N 0.000 description 1
- 230000005856 abnormality Effects 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 238000005868 electrolysis reaction Methods 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 150000002926 oxygen Chemical class 0.000 description 1
- 239000004810 polytetrafluoroethylene Substances 0.000 description 1
- 229920001343 polytetrafluoroethylene Polymers 0.000 description 1
- 239000000047 product Substances 0.000 description 1
- 230000000284 resting effect Effects 0.000 description 1
- 238000005245 sintering Methods 0.000 description 1
- 238000004544 sputter deposition Methods 0.000 description 1
- 238000007740 vapor deposition Methods 0.000 description 1
Landscapes
- Measuring Oxygen Concentration In Cells (AREA)
- Separation Using Semi-Permeable Membranes (AREA)
Description
【考案の詳細な説明】
本考案は電気化学装置、特に毒性を有するガス
のガス濃度を電気化学的に測定する電気化学的ガ
ス検知装置に関する。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electrochemical device, particularly an electrochemical gas detection device for electrochemically measuring the gas concentration of a toxic gas.
定電位電解法によりガス濃度を測定する方法は
よく知られている。この方法を用いるガス検知装
置では電解液中に作用電極、対電極、参照電極を
設け、作用電極と参照電極間に定電位を印加して
おき、作用電極上で生ずるガスの酸化還元反応に
より作用電極と対電極に生ずる電流を取り出し、
これよりガス濃度を測定している。 The method of measuring gas concentration by potentiostatic electrolysis is well known. In a gas detection device using this method, a working electrode, a counter electrode, and a reference electrode are provided in an electrolytic solution, and a constant potential is applied between the working electrode and the reference electrode. Take out the current generated at the electrode and counter electrode,
Gas concentration is measured from this.
例えば、一酸化炭素を測定する場合には作用電
極上で次のような酸化反応を生ずる。即ち、
CO＋H2O→CO2＋2H+＋2e-
一方、対電極では次のような還元反応を生ず
る。即ち、
1/2O2＋2H+＋2e-→H2O
このような酸化還元反応を利用するガス検知装
置では作用電極で反応するガスの量に見合つた量
のガスが対電極で反応することが必要である。と
ころが、従来のこの種ガス検知装置では作用電極
で反応するガス量が多い場合対電極で透過して反
応する酸素量が不足する場合があり、系の反応が
異常となり、また、参照電極の酸素電位が異常と
なり系全体が異常となる欠点があつた。 For example, when measuring carbon monoxide, the following oxidation reaction occurs on the working electrode. That is, CO+H 2 O→CO 2 +2H + +2e - On the other hand, the following reduction reaction occurs at the counter electrode. In other words, 1/2O 2 +2H + +2e - →H 2 O In a gas detection device that uses such a redox reaction, it is necessary that an amount of gas react at the counter electrode commensurate with the amount of gas reacting at the working electrode. It is. However, in conventional gas detection devices of this type, when the amount of gas reacting at the working electrode is large, the amount of oxygen that permeates and reacts at the counter electrode may be insufficient, resulting in abnormal system reactions and the oxygen at the reference electrode. There was a drawback that the potential became abnormal and the entire system became abnormal.
本考案は酸化還元反応を異常なく行い測定精度
を改善した電気化学的ガス検知装置を提供するこ
とを目的とする。 The object of the present invention is to provide an electrochemical gas detection device that performs redox reactions without abnormalities and improves measurement accuracy.
比較のため、第１図に従来のガス検知装置を概
略的に示す。図において、密封容器１内には電解
液が充満され、その電解液に接して作用電極３、
対電極４、参照電極５が互に離間して設けられて
いる。作用電極と参照電極間にはポテンシオスタ
ツト６より定電圧が印加されており、作用電極３
と対電極４で生じた酸化、還元反応によりリード
線７，８に電流が流れるようになつている。 For comparison, FIG. 1 schematically shows a conventional gas detection device. In the figure, a sealed container 1 is filled with an electrolyte, and a working electrode 3 is in contact with the electrolyte.
A counter electrode 4 and a reference electrode 5 are provided spaced apart from each other. A constant voltage is applied between the working electrode and the reference electrode by a potentiostat 6, and the working electrode 3
Current flows through the lead wires 7 and 8 due to the oxidation and reduction reactions occurring at the counter electrode 4 and the counter electrode 4.
作用電極３は金、銀、白金黒等の電極触媒能を
有する金属よりなり、この作用電極に測定対象ガ
ス、例えば一酸化炭素が接触するように作用電極
に面して密封容器１に気体透過膜９が張架され
る。気体透過膜は例えば弗素樹脂膜よりなり、一
酸化炭素を透過する。 The working electrode 3 is made of a metal having electrocatalytic ability such as gold, silver, platinum black, etc., and the gas permeates into the sealed container 1 facing the working electrode so that the gas to be measured, for example, carbon monoxide, comes into contact with the working electrode. The membrane 9 is stretched. The gas permeable membrane is made of, for example, a fluororesin membrane, and permeates carbon monoxide.
他方、作用電極３での酸化反応に対して逆の還
元反応を行う対電極４と参照電極５は作用電極３
より離間して設けられる。対電極４と参照電極５
に面して気体透過膜１０が設けられ、外部よりガ
スが対電極にアクセスできるようになつている。
気体透過膜は例えば弗素樹脂膜よりなり酸素を能
く透過する。 On the other hand, a counter electrode 4 and a reference electrode 5, which perform a reduction reaction opposite to the oxidation reaction at the working electrode 3, are the working electrode 3.
They are placed further apart. Counter electrode 4 and reference electrode 5
A gas permeable membrane 10 is provided facing the counter electrode so that gas can access the counter electrode from the outside.
The gas permeable membrane is made of, for example, a fluororesin membrane and effectively permeates oxygen.
気体透過膜１０の外側には還元作用に必要な酸
素をプールするための空気層１１を介在させて酸
素透過膜１２が設けられる。この酸素透過膜１２
は例えば弗素樹脂膜よりなり、酸素を通すが感知
すべき毒性ガスをほゞ完全に阻止するようになつ
ている。 An oxygen permeable membrane 12 is provided on the outside of the gas permeable membrane 10 with an air layer 11 interposed therebetween for pooling oxygen necessary for the reduction action. This oxygen permeable membrane 12
The sensor is made of, for example, a fluororesin film, which allows oxygen to pass through, but almost completely blocks out the toxic gas to be detected.
酸素−水のレドツクスカツプルの可逆性を最適
にするために参照電極の有効面積をできるだけ大
きくする必要がある。従つて、高濃度ガスが存在
する場合、あるいは長時間ガスが存在する場合、
反応電流が増加し、対電極及び参照電極表面にお
ける酸素不足となり、濃度表示に誤りが生じる。 In order to optimize the reversibility of the oxygen-water redox couple, it is necessary to make the effective area of the reference electrode as large as possible. Therefore, if there is a high concentration of gas or if the gas exists for a long time,
The reaction current increases, resulting in a lack of oxygen at the counter and reference electrode surfaces, resulting in erroneous concentration display.
本考案は前記の欠点を除去するために、対電極
及び参照電極の気体透過膜の空気と接触する側に
Pt、Ir、Rh、Au、Pd、Fe等の金属又はその酸化
物膜を付着することにより測定ガスの透過を阻止
し、酸素を充分に透過させるようにしたもので、
従来の酸素透過膜を不要とし、また、酸素透過膜
では酸素透過量が少ないために高濃度ガス及び連
続ガスの測定に際し、酸素不足を生じ、測定が不
可能であつたものを、前記方法により正常に測定
できるようにしたことを特徴とする。 In order to eliminate the above-mentioned drawbacks, the present invention has been developed to provide a gas-permeable membrane for the counter electrode and the reference electrode on the side that comes into contact with air.
A film of metals such as Pt, Ir, Rh, Au, Pd, Fe, etc. or their oxides is attached to prevent the measurement gas from passing through, while allowing sufficient oxygen to pass through.
The method described above eliminates the need for conventional oxygen-permeable membranes, and also eliminates the need for oxygen-permeable membranes, which cause insufficient oxygen when measuring high-concentration gases and continuous gases due to the small amount of oxygen permeable in oxygen-permeable membranes. It is characterized by allowing normal measurement.
第２図に本考案のガス検知装置の一実施例を概
略的に示す。図面において第１図の構成部分と同
一のものは同一参照符号で示し、説明の簡略化を
計つている。 FIG. 2 schematically shows an embodiment of the gas detection device of the present invention. In the drawings, the same components as those in FIG. 1 are designated by the same reference numerals to simplify the explanation.
本考案においては、例えば弗素樹脂膜
（PTFE）より気体透過膜９及び１０で電解液を
充満した容器１を密封し、気体透過膜１０の電解
液２と接する面には互に離間して対電極４と参照
電極５が設けられる。これらの対電極と参照電極
は金、銀、白金、白金黒等の電極触媒能を有する
金属を被着して形成される。気体透過膜１０の他
方の面、即ち気体に接する面にはPt、Ir、Rh、
Au、Pd、Fe等の金属、又はその酸化物をスパツ
タ、蒸着、焼結のような方法により被着して酸素
選択透過膜１３を形成する。 In the present invention, a container 1 filled with an electrolyte is sealed with gas-permeable membranes 9 and 10 made of, for example, a fluororesin membrane (PTFE), and the surface of the gas-permeable membrane 10 in contact with the electrolyte 2 is spaced apart from each other. An electrode 4 and a reference electrode 5 are provided. These counter electrodes and reference electrodes are formed by depositing a metal having electrocatalytic ability, such as gold, silver, platinum, or platinum black. The other surface of the gas permeable membrane 10, that is, the surface in contact with the gas, is coated with Pt, Ir, Rh,
The oxygen selectively permeable membrane 13 is formed by depositing metals such as Au, Pd, and Fe, or their oxides by a method such as sputtering, vapor deposition, or sintering.
第２図に示すような構成の本考案のガス検知装
置と、第１図に示すような構成の従来のガス検知
装置を用いて測定した測定結果を第３図に示す。
測定は測定ガスとして硫化水素（H2S）、
300PPMを８時間連続して与えて行われた。 FIG. 3 shows the measurement results obtained using the gas detection device of the present invention having the configuration as shown in FIG. 2 and the conventional gas detection device having the configuration as shown in FIG.
The measurement uses hydrogen sulfide (H 2 S) as the measurement gas,
The experiment was conducted by giving 300 PPM continuously for 8 hours.
第３図に示すように、高濃度のH2Sが連続して
存在すると点線イで示すように従来品は数時間後
に指示は低下し、H2Sの反応を止めて、空気に戻
すと、センサ出力はマイナス側に移動する。これ
は、参照電極の酸素不足により、静止電位が維持
できなくなつたためである。指示が低下したの
は、対電極での酸素不足により、酸素の還元反応
１／２O2＋2H+＋2e→H2Oが進行せず系の酸化還元
反応が成立しなくなつたためである。これに対
し、本考案の装置では図に実線ロで示すように、
測定時間中センサ出力は一定出力（300PPMに相
当とす出力）を指示し、長時間ガスを測定しても
還元反応に必要な酸素が欠乏することなく、酸素
選択透過膜１３を通して充分な酸素が吸入され、
そのため正常な酸化還元反応が行われる結果、ガ
スを高精度で測定できることになる。 As shown in Figure 3, when a high concentration of H 2 S is continuously present, the indication of the conventional product decreases after several hours, as shown by the dotted line A, and when the H 2 S reaction is stopped and the H 2 S is returned to air. , the sensor output moves to the negative side. This is because the resting potential could no longer be maintained due to lack of oxygen in the reference electrode. The indication decreased because the oxygen reduction reaction 1/2 O 2 +2H + +2e→H 2 O did not proceed due to the lack of oxygen at the counter electrode, and the redox reaction of the system was no longer established. In contrast, with the device of the present invention, as shown by the solid line B in the figure,
During the measurement period, the sensor output indicates a constant output (output equivalent to 300 PPM), and even if the gas is measured for a long time, the oxygen necessary for the reduction reaction will not be depleted, and sufficient oxygen will be supplied through the oxygen selective permeation membrane 13. inhaled,
Therefore, as a result of normal redox reaction, gas can be measured with high accuracy.
以上説明したように、本考案によると、対電極
及び参照電極に充分な酸素が供給されるため、連
続して長時間ガスを測定したり、或いは一時的に
ガス濃度が増大するような条件下で測定しても常
に正常なガス測定が可能であり、しかもその精度
は高く、測定結果を信頼することができる。 As explained above, according to the present invention, sufficient oxygen is supplied to the counter electrode and the reference electrode, so that gas can be measured continuously for a long time or under conditions where the gas concentration temporarily increases. Normal gas measurements are always possible even when measured with a high accuracy, and the measurement results can be trusted.
また、本考案によると、酸素選択透過膜を気体
透過膜に直接被着して形成するから、従来のよう
に酸素をプールするような複雑な構成をとる必要
がなく、構造簡単で容易に製作できる。 In addition, according to the present invention, since the oxygen selectively permeable membrane is formed by directly adhering to the gas permeable membrane, there is no need for a complicated configuration such as pooling oxygen as in the past, and the structure is simple and easy to manufacture. can.
第１図は従来のガス検知装置の概略図、第２図
は本考案のガス検知装置の一実施例の概略図、第
３図は第１図と第２図の装置のガス測定結果を示
すグラフ図である。
主要部分の符号の説明、密封容器……１、電解
液……２、作用電極……３、対電極……４、参照
電極……５、気体透過膜……９，１０、酸素選択
透過膜……１３。
Fig. 1 is a schematic diagram of a conventional gas detection device, Fig. 2 is a schematic diagram of an embodiment of the gas detection device of the present invention, and Fig. 3 shows gas measurement results of the device shown in Figs. 1 and 2. It is a graph diagram. Explanation of symbols of main parts, sealed container...1, electrolyte...2, working electrode...3, counter electrode...4, reference electrode...5, gas permeable membrane...9, 10, oxygen selective permeable membrane ...13.
Claims (1)
極、及び参照電極を夫々離間して設置し、該作用
電極、対電極及び参照電極を気体透過膜を通して
外部雰囲気に連通するようにした電気化学的ガス
検知装置において、気体透過膜の電解液側の面に
電極触媒能を持つ金属を被着して対電極及び参照
電極とし、該気体透過膜の他方の面に金属又はそ
の金属酸化物を被着して酸素選択透過膜を形成し
てなることを特徴とする電気化学的ガス検知装
置。 Electrochemistry in which a working electrode, a counter electrode, and a reference electrode are installed separately in a sealed container filled with an electrolytic solution, and the working electrode, counter electrode, and reference electrode are communicated with the external atmosphere through a gas permeable membrane. In a gas detection device, a metal having electrocatalytic ability is coated on the electrolyte side surface of the gas permeable membrane to serve as a counter electrode and a reference electrode, and a metal or its metal oxide is coated on the other surface of the gas permeable membrane. An electrochemical gas detection device characterized by being formed by depositing an oxygen selectively permeable membrane.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP8701083U JPS59194055U (en) | 1983-06-09 | 1983-06-09 | electrochemical gas detection device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP8701083U JPS59194055U (en) | 1983-06-09 | 1983-06-09 | electrochemical gas detection device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS59194055U JPS59194055U (en) | 1984-12-24 |
| JPH0334690Y2 true JPH0334690Y2 (en) | 1991-07-23 |
Family
ID=30216932
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP8701083U Granted JPS59194055U (en) | 1983-06-09 | 1983-06-09 | electrochemical gas detection device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS59194055U (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6288955A (en) * | 1985-10-15 | 1987-04-23 | Shinkosumosu Denki Kk | Gas sensor having gaseous hydrogen halide selectivity |
-
1983
- 1983-06-09 JP JP8701083U patent/JPS59194055U/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS59194055U (en) | 1984-12-24 |
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