JPH03186755A - Galvanyl battery type combustible gas sensor - Google Patents
Galvanyl battery type combustible gas sensorInfo
- Publication number
- JPH03186755A JPH03186755A JP1327639A JP32763989A JPH03186755A JP H03186755 A JPH03186755 A JP H03186755A JP 1327639 A JP1327639 A JP 1327639A JP 32763989 A JP32763989 A JP 32763989A JP H03186755 A JPH03186755 A JP H03186755A
- Authority
- JP
- Japan
- Prior art keywords
- combustible gas
- electrode
- negative electrode
- gas
- positive 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.)
- Granted
Links
- 239000007789 gas Substances 0.000 claims abstract description 56
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims abstract description 18
- 239000001301 oxygen Substances 0.000 claims abstract description 18
- 229910052760 oxygen Inorganic materials 0.000 claims abstract description 18
- 239000003054 catalyst Substances 0.000 claims abstract description 13
- 238000006722 reduction reaction Methods 0.000 claims abstract description 11
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical group [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 claims abstract description 9
- 239000010931 gold Substances 0.000 claims abstract description 9
- 229910052737 gold Inorganic materials 0.000 claims abstract description 9
- 238000006243 chemical reaction Methods 0.000 claims abstract description 6
- 239000003792 electrolyte Substances 0.000 claims abstract description 4
- 238000006056 electrooxidation reaction Methods 0.000 claims description 3
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 abstract description 12
- 238000007254 oxidation reaction Methods 0.000 abstract description 10
- QTBSBXVTEAMEQO-UHFFFAOYSA-N Acetic acid Chemical compound CC(O)=O QTBSBXVTEAMEQO-UHFFFAOYSA-N 0.000 abstract description 6
- 229910052697 platinum Inorganic materials 0.000 abstract description 6
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 abstract description 5
- 229910052799 carbon Inorganic materials 0.000 abstract description 5
- SCVFZCLFOSHCOH-UHFFFAOYSA-M potassium acetate Chemical compound [K+].CC([O-])=O SCVFZCLFOSHCOH-UHFFFAOYSA-M 0.000 abstract description 4
- 229920000122 acrylonitrile butadiene styrene Polymers 0.000 abstract description 2
- 229920001577 copolymer Polymers 0.000 abstract description 2
- -1 polyfluoroethylene Polymers 0.000 abstract description 2
- 235000011056 potassium acetate Nutrition 0.000 abstract description 2
- 238000007740 vapor deposition Methods 0.000 abstract description 2
- 239000008246 gaseous mixture Substances 0.000 abstract 1
- 239000003863 metallic catalyst Substances 0.000 abstract 1
- 239000000203 mixture Substances 0.000 abstract 1
- BFKJFAAPBSQJPD-UHFFFAOYSA-N tetrafluoroethene Chemical group FC(F)=C(F)F BFKJFAAPBSQJPD-UHFFFAOYSA-N 0.000 abstract 1
- KDLHZDBZIXYQEI-UHFFFAOYSA-N Palladium Chemical compound [Pd] KDLHZDBZIXYQEI-UHFFFAOYSA-N 0.000 description 8
- 229910052763 palladium Inorganic materials 0.000 description 4
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 description 3
- 229910002091 carbon monoxide Inorganic materials 0.000 description 3
- 238000001514 detection method Methods 0.000 description 3
- 239000008151 electrolyte solution Substances 0.000 description 3
- 239000001257 hydrogen Substances 0.000 description 3
- 229910052739 hydrogen Inorganic materials 0.000 description 3
- 239000012528 membrane Substances 0.000 description 3
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- YADSGOSSYOOKMP-UHFFFAOYSA-N dioxolead Chemical compound O=[Pb]=O YADSGOSSYOOKMP-UHFFFAOYSA-N 0.000 description 2
- 238000005868 electrolysis reaction Methods 0.000 description 2
- 150000002431 hydrogen Chemical class 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- 229920000620 organic polymer Polymers 0.000 description 2
- MYMOFIZGZYHOMD-UHFFFAOYSA-N Dioxygen Chemical compound O=O MYMOFIZGZYHOMD-UHFFFAOYSA-N 0.000 description 1
- 230000002378 acidificating effect Effects 0.000 description 1
- 239000007864 aqueous solution Substances 0.000 description 1
- 230000003197 catalytic effect Effects 0.000 description 1
- 229910001882 dioxygen Inorganic materials 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000005611 electricity Effects 0.000 description 1
- 210000003734 kidney Anatomy 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 229910044991 metal oxide Inorganic materials 0.000 description 1
- 150000004706 metal oxides Chemical class 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 238000010792 warming Methods 0.000 description 1
Abstract
Description
【発明の詳細な説明】
産業上の利用分野
本発明は、空気中に含まれた可燃性ガスの濃度を測定す
るための電気化学式可燃性ガスセンサに関するものであ
る。さらに詳しくは、ガス極よりなる正極と負極、隔膜
、電解液および容器とから構成されるガルバニ電池式可
燃性ガスセンサに関するものである。DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an electrochemical combustible gas sensor for measuring the concentration of combustible gas contained in air. More specifically, the present invention relates to a galvanic cell-type combustible gas sensor that is composed of a positive electrode made of a gas electrode, a negative electrode, a diaphragm, an electrolytic solution, and a container.
従来の技術
電気化学式可燃性ガスセンサは、−殻内に可燃性ガスの
電気化学的酸化反応に有効な触媒金属と、その外側に位
置し可燃性ガスの供給を制限するための有機高分子膜か
らなる隔膜とで構成されるガス極を負極とするが、正極
としては二酸化鉛等の金ｇ酸化物を用いるものと、酸素
の電気化学的還元反応に有効な白金やパラジウム等の触
媒からなるガス極を用いるものとがある。Conventional technology Electrochemical flammable gas sensors consist of - a catalytic metal effective for the electrochemical oxidation reaction of flammable gas in the shell and an organic polymer membrane located outside the shell to limit the supply of flammable gas. The negative electrode is a gas electrode consisting of a diaphragm, while the positive electrode is made of gold g oxide such as lead dioxide, and a gas consisting of a catalyst such as platinum or palladium, which is effective for the electrochemical reduction reaction of oxygen. Some use poles.
前者においては、金属酸化物の酸化還元電位が酸素のそ
れに比べて責なため、負極の電位を酸素の酸化還元電位
よりも卑な電位に保って、負極における酸素の発生を防
止すると同時に、該電位を可燃性ガスの酸化還元電位よ
りも責な電位に保って可燃性ガスの酸化反応を促進しな
ければならない。In the former case, since the redox potential of the metal oxide is higher than that of oxygen, the potential of the negative electrode is kept at a potential lower than the redox potential of oxygen to prevent the generation of oxygen at the negative electrode. The oxidation reaction of the combustible gas must be promoted by maintaining the potential at a higher potential than the redox potential of the combustible gas.
一方、後者においては、正極に酸素ガス極を用いるため
負極において酸素の発生は起こらないが、触媒としての
白金やパラジウムが酸素の還元反応ばかりでなく可燃性
ガスの酸化反応にも有効なため正極では酸素の還元反応
のみが、負極では可燃性ガスの酸化反応のみが起こるよ
うにする必要から正極の電位を酸素の酸化還元電位より
も卑な電位に、負極の電位を可燃性ガスの酸化還元電位
よりも責な電位に保たなければならない、いずれの場合
も電極電位を一定に保って電解を行うため、この方式は
定電位電解方式と呼ばれている。On the other hand, in the latter case, since an oxygen gas electrode is used as the positive electrode, no oxygen is generated at the negative electrode, but platinum or palladium as a catalyst is effective not only for the reduction reaction of oxygen but also for the oxidation reaction of combustible gases, so the positive electrode Since it is necessary to ensure that only the reduction reaction of oxygen occurs at the negative electrode and only the oxidation reaction of combustible gas at the negative electrode, the potential of the positive electrode is set to a potential that is more base than the redox potential of oxygen, and the potential of the negative electrode is set to a potential that is lower than the redox potential of combustible gas. This method is called a constant-potential electrolysis method because the electrode potential must be maintained at a constant level in both cases.
発明が解決しようとする課題
上述したように、従来の電気化学式可燃性ガスセンサは
負極での酸素発生や酸素の還元反応を防ぐためにポテン
シオスタットなどの高価で取扱い難い定電位印加装置を
必要とするうえ、電極に電位を印加してからセンサの出
力が安定するまでに相当の時間が必要で、測定したい時
に即座に測れないという問題点がある。Problems to be Solved by the Invention As mentioned above, conventional electrochemical combustible gas sensors require an expensive and difficult-to-handle constant potential application device such as a potentiostat to prevent oxygen generation and oxygen reduction reactions at the negative electrode. Moreover, it takes a considerable amount of time for the output of the sensor to stabilize after applying a potential to the electrodes, which poses the problem that measurements cannot be taken immediately when desired.
この様な問題点を解消するためには、センサの作動方式
をガルバニ電池方式にすればよいのだが従来のセンサで
は上述したように負極で酸素が発生したり空気中の酸素
の還元反応が起こってしまうという問題があるため、定
電位電解方式にせざるを得なかった。In order to solve these problems, the sensor could be operated using a galvanic cell system, but as mentioned above, with conventional sensors, oxygen is generated at the negative electrode or a reduction reaction of oxygen in the air occurs. Because of this problem, a constant potential electrolysis method had to be used.
課題を解決するための手段
本発明は金触媒が酸素の電気化学的還元反応には活性で
あるが、可燃性ガスの電気化学的酸化反応には不活性で
あることに着目してなされたものである。Means for Solving the Problems The present invention was made based on the fact that gold catalysts are active in electrochemical reduction reactions of oxygen, but are inactive in electrochemical oxidation reactions of combustible gases. It is.
即ち、本発明は正極に酸素の還元反応には活性で可燃性
ガスの酸化反応には不活性な金触媒より構成されるガス
極を用い、負極に可燃性ガスの酸化反応に活性な白金や
パラジウム等の触媒より構成されるガス極を用いること
により、ガルバニ電池方式の可燃性ガスセンサを可能な
らしめるものである。That is, the present invention uses a gas electrode composed of a gold catalyst active in the reduction reaction of oxygen and inert in the oxidation reaction of combustible gas as the positive electrode, and a gas electrode composed of a gold catalyst active in the oxidation reaction of combustible gas as the negative electrode. By using a gas electrode made of a catalyst such as palladium, a galvanic cell type combustible gas sensor is made possible.
なお、ガルバニ電池式センサは、センサ自身が電池とし
て幼くため、外部から電圧を印加する必要がないうえ、
正極と負極とを抵抗を介して接続し、常に動作状態にし
であるため、ウオーミングアツプなしで即座に測定が可
能という長所を持っている。In addition, with galvanic battery type sensors, since the sensor itself is a small battery, there is no need to apply voltage from the outside.
Since the positive and negative electrodes are connected via a resistor and are always in operation, it has the advantage that measurements can be taken immediately without warming up.
作用
金触媒よりなる正極としてのガス極と、白金またはパラ
ジウム触媒よりなる負極としてのガス極と、該負極の外
側に圧接して設けられた有機高分子膜からなる隔膜と、
電解液と、これらを収納する容器と、さらに正極と負極
とを結ぶ抵抗器とで構成されるガルバニ電池式可燃性ガ
スセンサを空気と可燃性ガスとの混合ガス中に置くと、
正極では酸素の還元反応のみが、従って負極では可燃性
ガスの酸化反応のみが起こる。可燃性ガスの一例として
一酸化炭素を用いてこれらの反応式を下記に示す。A gas electrode as a positive electrode made of a working gold catalyst, a gas electrode as a negative electrode made of a platinum or palladium catalyst, and a diaphragm made of an organic polymer membrane provided in pressure contact with the outside of the negative electrode.
When a galvanic cell-type flammable gas sensor consisting of an electrolytic solution, a container for storing these, and a resistor connecting a positive electrode and a negative electrode is placed in a mixed gas of air and flammable gas,
Only the reduction reaction of oxygen occurs at the positive electrode, and therefore only the oxidation reaction of combustible gas occurs at the negative electrode. These reaction formulas are shown below using carbon monoxide as an example of flammable gas.
電解液が酸性の場合
正極では ÷０２＋２１１” −ｔ−２ｅ−−＋ Ｈ２
０負極では ＣＯ＋ Ｈ２０→Ｃｏ、 ＋２８” ＋２
ｅ−全体として ＴＯ□十ＣＯ→ ＣＯ２
電解液がアルカリ性の場合
正極では −７０２＋ Ｈ２０＋２ｅ−→２０Ｈ−負極
では ＣＯ＋２叶−−ＣＯ２＋Ｈ２０＋２ｅ全体として
丁０２ ＋Ｃ０−ＣＯ２
このように正極では酸素の還元反応のみが起こり、可燃
性ガスの酸化反応が起こらないのは本発明が着目した金
触媒のガス選択性によるものである。When the electrolyte is acidic, at the positive electrode ÷02+211” -t-2e--+ H2
0 negative electrode: CO+ H20→Co, +28” +2
e- as a whole TO The reason why the oxidation reaction of combustible gas does not occur is due to the gas selectivity of the gold catalyst, which is the focus of the present invention.
上記の反応に伴い、負極から抵抗器を通って正極へ電子
が移動するので抵抗器の両端の電圧を測定することによ
り両電極間に流れた電気量、換言すれば可燃性ガスの濃
度を知ることができる。Along with the above reaction, electrons move from the negative electrode to the positive electrode through the resistor, so by measuring the voltage across the resistor, we can determine the amount of electricity flowing between the two electrodes, in other words, the concentration of flammable gas. be able to.
実施例 以下、本発明を好適な実施例を用いて説明する。Example The present invention will be explained below using preferred embodiments.
第１図は本発明の一実施例に係るガルバニ電池式可燃性
ガスセンサの断面楕遠国である。本センサは、ＡＢＳ樹
脂製の容器本体１とポーラスカーボンに金蒸着を施し、
その外側に多孔性のポリフルオロエチレン膜を圧接して
一体化したガス極として機能する正極２、ポーラスカー
ボンに白金を電着させた負極３、酢酸と酢酸カリの混合
水溶液からなる電解液４、さらに負極の外側に設けられ
た４フッ化エチレン−６フツ化プロピレン共重合体膜か
らなる隔膜５より構成されており、正極と負極は検出抵
抗６を介して外部で閉じている。FIG. 1 is an oval cross-sectional view of a galvanic cell type combustible gas sensor according to an embodiment of the present invention. This sensor has a container body 1 made of ABS resin and porous carbon coated with gold vapor deposition.
A positive electrode 2 which functions as an integrated gas electrode by pressing a porous polyfluoroethylene membrane on the outside thereof, a negative electrode 3 having platinum electrodeposited on porous carbon, an electrolytic solution 4 consisting of a mixed aqueous solution of acetic acid and potassium acetate, It further includes a diaphragm 5 made of a tetrafluoroethylene-hexafluoropropylene copolymer film provided outside the negative electrode, and the positive and negative electrodes are closed externally via a detection resistor 6.
このガルバニ電池式可燃性ガスセンサを可燃性ガスであ
る水素（Ｈ２）または−酸化炭素（Ｃｏ）の濃度が２．
６．１０％の空気中に放置して、検出抵抗６の両端で検
出される出力電圧を第２図に１０ヅトした。This galvanic cell type combustible gas sensor is used when the concentration of combustible gas hydrogen (H2) or -carbon oxide (Co) is 2.
6. The output voltage detected at both ends of the detection resistor 6 was set at 10° as shown in FIG. 2 when the sensor was left in 10% air.
第２図より、本発明によるガルバニ電池式可燃性ガスセ
ンサは水素または一酸化炭素の空気中での濃度に対し潰
れた直線性があることがわかる。From FIG. 2, it can be seen that the galvanic cell type combustible gas sensor according to the present invention has flat linearity with respect to the concentration of hydrogen or carbon monoxide in the air.
このことは、可燃性ガスセンサでも本発明を採用すれば
ガルバニ電池方式が可能となることを意味する。This means that if the present invention is adopted in a combustible gas sensor, a galvanic cell system becomes possible.
発明の効果
本発明によるガルバニ電池式可燃性ガスセンサは、定電
位印加装置を用いる必要がないうえ、即座に空気中の可
燃性ガス濃度を検出することができるものである０本セ
ンサを使用することにより、安価で消費電力が少なく取
扱いの簡単な可燃性ガス濃度計や、警報器の提供が可能
となるので産業上に寄与すること非常に大である。Effects of the Invention The galvanic cell type combustible gas sensor according to the present invention does not require the use of a constant potential application device, and uses a zero-wire sensor that can immediately detect the concentration of combustible gas in the air. This makes it possible to provide combustible gas concentration meters and alarms that are inexpensive, consume little power, and are easy to handle, making a huge contribution to industry.
第１図は本発明の一実施例に係るガルバニ電池式ガスセ
ンサの断面構造図である。第２図は空気中の水素または
一酸化炭素濃度とセンサの出力電圧との関係を示した図
である。
１・・・容器本体、２・・・正極、３・・・負極。
５・・・隔膜、６・・・検出抵抗
４・・・電解液。
腎
閃
４牽巽剃代
芽
阿FIG. 1 is a cross-sectional structural diagram of a galvanic cell type gas sensor according to an embodiment of the present invention. FIG. 2 is a diagram showing the relationship between the concentration of hydrogen or carbon monoxide in the air and the output voltage of the sensor. 1... Container body, 2... Positive electrode, 3... Negative electrode. 5... Diaphragm, 6... Detection resistor 4... Electrolyte. Kidney Flash 4 Katsumi Shashiro Mea
Claims (1)
極として機能する正極と、可燃性ガスの電気化学的酸化
反応に有効な触媒よりなりガス極として機能する負極と
、電解液とこれらを収納する容器とで基本的に構成され
る電気化学式可燃性ガスセンサにおいて、該正極触媒と
して金を用いたことを特徴とするガルバニ電池式可燃性
ガスセンサ。Contains a positive electrode that is made of a catalyst that is effective for the electrochemical reduction reaction of oxygen and functions as a gas electrode, a negative electrode that is made of a catalyst that is effective for the electrochemical oxidation reaction of combustible gas, and that functions as a gas electrode, and an electrolyte. 1. A galvanic cell type combustible gas sensor, characterized in that the electrochemical type combustible gas sensor basically consists of a container and a container, wherein gold is used as the positive electrode catalyst.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1327639A JPH0769303B2 (en) | 1989-12-18 | 1989-12-18 | Galvanic battery type flammable gas sensor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1327639A JPH0769303B2 (en) | 1989-12-18 | 1989-12-18 | Galvanic battery type flammable gas sensor |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH03186755A true JPH03186755A (en) | 1991-08-14 |
| JPH0769303B2 JPH0769303B2 (en) | 1995-07-26 |
Family
ID=18201301
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1327639A Expired - Lifetime JPH0769303B2 (en) | 1989-12-18 | 1989-12-18 | Galvanic battery type flammable gas sensor |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0769303B2 (en) |
-
1989
- 1989-12-18 JP JP1327639A patent/JPH0769303B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0769303B2 (en) | 1995-07-26 |
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