JPH09138215A - Electrochemical hydrogen sensor - Google Patents
Electrochemical hydrogen sensorInfo
- Publication number
- JPH09138215A JPH09138215A JP7319547A JP31954795A JPH09138215A JP H09138215 A JPH09138215 A JP H09138215A JP 7319547 A JP7319547 A JP 7319547A JP 31954795 A JP31954795 A JP 31954795A JP H09138215 A JPH09138215 A JP H09138215A
- Authority
- JP
- Japan
- Prior art keywords
- electrode
- diaphragm
- hydrogen
- sensor
- working 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.)
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Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、電気化学式水素セ
ンサ技術の分野に属するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention belongs to the field of electrochemical hydrogen sensor technology.
【０００２】[0002]
【従来技術】電気化学式水素センサは、常温常圧で作動
し、小型・軽量であって、しかも安価であることから、
半導体工場、化学工場、実験室などの水素ガス使用場所
でのガス漏れ監視やガス濃度計として使用されている。2. Description of the Related Art Electrochemical hydrogen sensors operate at room temperature and pressure, are small and lightweight, and are inexpensive.
It is used as a gas leak monitor and a gas concentration meter in hydrogen gas usage places such as semiconductor factories, chemical factories, and laboratories.
【０００３】この電気化学式水素センサは、一般に、電
気化学的酸化反応に有効な白金又は白金族触媒よりなる
水素検知用の作用極と、対極と、これらの電極に接触す
る電解液と、水素を選択的に透過する隔膜とを備えた二
極式と、これに参照極を具備した三極式の電気化学式水
素センサとがある。This electrochemical hydrogen sensor generally detects a working electrode for detecting hydrogen, which is made of platinum or a platinum group catalyst effective for an electrochemical oxidation reaction, a counter electrode, an electrolytic solution in contact with these electrodes, and hydrogen. There are a bipolar type sensor having a selectively permeable diaphragm and a three-pole type electrochemical hydrogen sensor having a reference electrode.
【０００４】測定原理としては、特に二極式について述
べるが、作用極と対極との間が常に一定の電位に保たれ
ており、隔膜を通過した水素が、隔膜と作用極との間に
形成される電解液中に溶解していき、作用極上において
酸化される。そして、電解液を介して対極との間で電気
化学反応が起こり、そのときに作用極と対極との間に流
れる電流が水素ガス濃度に比例することを利用して、電
流値より水素ガス濃度を知るものである。The bipolar principle will be particularly described as the measurement principle. However, a constant potential is always maintained between the working electrode and the counter electrode, and hydrogen passing through the diaphragm is formed between the diaphragm and the working electrode. Is dissolved in the electrolytic solution and is oxidized on the working electrode. Then, an electrochemical reaction occurs between the counter electrode and the electrolytic solution, and the fact that the current flowing between the working electrode and the counter electrode at that time is proportional to the hydrogen gas concentration is used to calculate the hydrogen gas concentration from the current value. To know.
【０００５】ところで、電気化学式センサにおいて、検
知ガスが反応を起こす部分、つまり隔膜及び作用極部分
の構造は、センサが良好な性能を有するか否かを決める
非常に重要な部分である。By the way, in the electrochemical sensor, the structure where the detection gas reacts, that is, the structure of the diaphragm and the working electrode, is a very important part for determining whether or not the sensor has good performance.
【０００６】この隔膜と触媒電極である作用極との構造
としては、隔膜と触媒電極である作用極とが単に機械的
な接触をしているだけのタイプ（例えば特開昭５８−１
８７８４６号）、両者が蒸着や圧着等の手段によって隔
膜に一体接合されているタイプ（例えば英国特許１２０
０６９６号）とに大別される。The structure of the diaphragm and the working electrode, which is the catalyst electrode, is of a type in which the diaphragm and the working electrode, which is the catalyst electrode, are merely in mechanical contact (for example, JP-A-58-1).
No. 87846), both of which are integrally joined to the diaphragm by means such as vapor deposition or pressure bonding (for example, British Patent 120
No. 0696).
【０００７】前者の場合、触媒電極は金属の円板もしく
は円柱形状に形成されており、検知ガスは、まず隔膜を
透過し、次に隔膜と触媒電極との間に形成される電解液
に溶解していき、電極上で反応する。このとき、常に隔
膜と触媒電極である作用極との接触状態を一定に保ち、
電解液膜の厚さが変わらないようにすることが必要とな
る。なぜなら、圧力や湿度が変化するような環境では、
この電解液膜の厚さが一定とならず、センサ出力が不安
定になるからである。In the former case, the catalyst electrode is formed in the shape of a metal disk or column, and the detection gas first permeates through the diaphragm and then dissolves in the electrolytic solution formed between the diaphragm and the catalyst electrode. And then react on the electrodes. At this time, always keep the contact state between the diaphragm and the working electrode, which is the catalyst electrode, constant,
It is necessary to keep the thickness of the electrolyte membrane unchanged. Because in an environment where pressure and humidity change,
This is because the thickness of this electrolyte membrane is not constant and the sensor output becomes unstable.
【０００８】一方、後者の場合、隔膜を透過してきたガ
スは、多孔性の触媒電極である作用極の孔中に浸透した
電解液と触媒電極である作用極との界面で反応する。こ
の場合、隔膜と触媒電極である作用極とは一体化されて
いるので、たとえ外圧が変化して隔膜が膨らんだりへこ
んだりしたとしても、センサ出力が不安定になることは
ない。On the other hand, in the latter case, the gas that has permeated the diaphragm reacts at the interface between the electrolytic solution that has penetrated into the pores of the working electrode, which is a porous catalyst electrode, and the working electrode, which is the catalyst electrode. In this case, since the diaphragm and the working electrode, which is the catalyst electrode, are integrated, the sensor output will not become unstable even if the external pressure changes and the diaphragm swells or dents.
【０００９】それゆえに、機械的接触のものに比べ、隔
膜と作用極とが一体化されたものの方がよりセンサ出力
が安定したものとなる。Therefore, the sensor output is more stable in the case where the diaphragm and the working electrode are integrated as compared with the case where the diaphragm is in mechanical contact.
【００１０】[0010]
【発明が解決しようとする課題】しかしながら、隔膜と
触媒電極とを一体に接合した構造の電気化学式水素セン
サであっても、高濃度条件下でセンサ出力が低下した
り、不安定になったりすることがある。そのため、安全
上の問題からより高性能のセンサが望まれている。However, even with an electrochemical hydrogen sensor having a structure in which a diaphragm and a catalyst electrode are integrally joined, the sensor output may drop or become unstable under high concentration conditions. Sometimes. Therefore, a higher performance sensor is desired due to safety concerns.
【００１１】そこで、本発明は、高濃度条件下であって
もセンサの直線性精度がよく、かつドリフトが極めて少
ない優れた電気化学式酸素センサを提供することを目的
とする。Therefore, it is an object of the present invention to provide an excellent electrochemical oxygen sensor which has a high linearity accuracy of the sensor even under a high concentration condition and has an extremely small drift.
【００１２】[0012]
【課題を解決するための手段】本発明は、水素を電気化
学的に酸化する作用極と、水素透過性を有する隔膜とを
備えてなる電気化学式水素センサにおいて、該作用極
は、白金を主成分とする触媒電極であって、かつ隔膜の
片面に一体接合されており、該触媒電極の厚さが１００
オングストロームから５００オングストロームであるこ
とを特徴とする。The present invention relates to an electrochemical hydrogen sensor comprising a working electrode for electrochemically oxidizing hydrogen and a diaphragm having hydrogen permeability, wherein the working electrode is mainly platinum. It is a catalyst electrode as a component and is integrally joined to one surface of the diaphragm, and the thickness of the catalyst electrode is 100
It is characterized in that it is from angstrom to 500 angstrom.
【００１３】[0013]
【発明の実施の形態】以下、本発明の好適な一実施の形
態について具体的に詳述する。BEST MODE FOR CARRYING OUT THE INVENTION A preferred embodiment of the present invention will be described in detail below.
【００１４】図１は、本発明になる電気化学式水素セン
サの断面構造図である。FIG. 1 is a sectional structural view of an electrochemical hydrogen sensor according to the present invention.
【００１５】同図において、１は作用極である触媒電
極、２は対極、３は電解液、４は隔膜であり、厚さ５０
μｍのフッ素系高分子薄膜（４フッ化エチレン−６フッ
化プロピレン共重合体）である。In the figure, 1 is a catalyst electrode which is a working electrode, 2 is a counter electrode, 3 is an electrolytic solution, 4 is a diaphragm, and a thickness is 50.
It is a fluorine-based polymer thin film (tetrafluoroethylene-6-fluoropropylene copolymer) of μm.
【００１６】５はＯ−リング、６は円筒形の容器、７は
抵抗、８は集電体、１１は隔膜４と触媒電極１との接合
体である。Reference numeral 5 is an O-ring, 6 is a cylindrical container, 7 is a resistor, 8 is a current collector, and 11 is a joined body of the diaphragm 4 and the catalyst electrode 1.
【００１７】隔膜４と作用極としての触媒電極１との一
体接合は、スパッタリングもしくは真空蒸着により、隔
膜４の片面に白金触媒薄層を形成させて行う。ここで
は、隔膜の中央に円形の薄層を形成させている。The integral bonding of the diaphragm 4 and the catalyst electrode 1 as the working electrode is carried out by forming a platinum catalyst thin layer on one surface of the diaphragm 4 by sputtering or vacuum deposition. Here, a circular thin layer is formed in the center of the diaphragm.
【００１８】この隔膜と触媒電極との接合体１１をＯ−
リング５を用いて容器６の一端に固定保持し、触媒電極
と容器６の中央上面に設けた多孔性カーボンの集電体８
とが接するようにしている。この集電体８には、リード
が取り付けられ容器外のポテンショスタットに接続され
ている。The bonded body 11 of the diaphragm and the catalyst electrode is formed by O-
A porous carbon current collector 8 fixedly held at one end of the container 6 using a ring 5 and provided on the upper surface of the center of the catalyst electrode and the container 6.
I try to make contact with. A lead is attached to the current collector 8 and is connected to a potentiostat outside the container.
【００１９】対極２は、ベータ型二酸化鉛であり、参照
極としての機能も兼ねている。ここでは、容器内壁外周
面に設けられており、対極２に取り付けられたリードが
容器外で抵抗７の両端に接続されている。そして、その
一端がポテンショスタットに接続されている。 加え
て、作用極１と対極２との間に一定の電位が保たれてい
る。The counter electrode 2 is beta-type lead dioxide and also functions as a reference electrode. Here, the lead provided on the outer peripheral surface of the inner wall of the container and attached to the counter electrode 2 is connected to both ends of the resistor 7 outside the container. And one end thereof is connected to the potentiostat. In addition, a constant potential is maintained between the working electrode 1 and the counter electrode 2.
【００２０】電解液３は、酢酸６モル／リットルと酢酸カリウ
ム３モル／リットルと酢酸鉛０．１モル／リットルとの混合液であ
り、容器内に満たされている。The electrolytic solution 3 is a mixed solution of 6 mol / l of acetic acid, 3 mol / l of potassium acetate and 0.1 mol / l of lead acetate, and is filled in the container.
【００２１】上述の構造のセンサであって、触媒電極１
の厚さを５０、１００、３００、５００、７００、１５
００ミクロンとしたセンサを作成し、１００％水素雰囲
気中におけるセンサ出力の変化（ドリフト）及びセンサ
出力の水素濃度に対する直線性の精度について試験を行
った。A sensor having the above structure, wherein the catalyst electrode 1
The thickness of 50, 100, 300, 500, 700, 15
A sensor having a size of 00 μm was prepared, and a change in the sensor output (drift) in a 100% hydrogen atmosphere and a linearity accuracy of the sensor output with respect to the hydrogen concentration were tested.
【００２２】１００％水素雰囲気中におけるセンサ出力
の変化は、１００％水素雰囲気中に各センサを放置し、
その経時変化を追った。また、センサ出力の水素濃度に
対する直線性の精度については、水素濃度５０、７０お
よび９０パーセントのガスを各センサで濃度測定したと
きの誤差を求めた。The change of the sensor output in the 100% hydrogen atmosphere is caused by leaving each sensor in the 100% hydrogen atmosphere.
The change over time was followed. Regarding the accuracy of the linearity of the sensor output with respect to the hydrogen concentration, an error was obtained when the concentrations of gases having hydrogen concentrations of 50, 70 and 90% were measured by the respective sensors.
【００２３】その結果を表１に示す。Table 1 shows the results.
【００２４】尚、表中の直線性精度の値は、各濃度ガス
でほぼ同一の結果を示した。The linearity accuracy values in the table show almost the same results for each concentration gas.
【００２５】[0025]
【表１】 [Table 1]
【００２６】表１より、Ｎｏ．２、３、４のセンサが各
特性において良好な値を示しており、触媒電極の厚さと
して、１００から５００オングストロームが適している
ことがわかる。さらに、白金を主成分とし、白金族との
二元系、三元系の作用極についても上記と同様の結果を
得た。From Table 1, No. The sensors 2, 3 and 4 show good values in each characteristic, and it can be seen that the thickness of the catalyst electrode is preferably 100 to 500 Å. Furthermore, the same results as above were obtained for binary and ternary working electrodes containing platinum as a main component and platinum group.
【００２７】尚、ここでは二極式について述べたが、三
極式のものであっても同様の効果が得られることは言う
までもない。Although the two-pole type has been described here, it goes without saying that the same effect can be obtained even with the three-pole type.
【００２８】[0028]
【発明の効果】本発明は、水素を電気化学的に酸化する
作用極と、水素透過性を有する隔膜とを備えてなる電気
化学式水素センサにおいて、該作用極は、白金を主成分
とする触媒電極であって、かつ隔膜の片面に一体接合さ
れており、該触媒電極の厚さが１００オングストローム
から５００オングストロームであることを特徴とする。Industrial Applicability The present invention provides an electrochemical hydrogen sensor comprising a working electrode for electrochemically oxidizing hydrogen and a hydrogen permeable diaphragm, wherein the working electrode is a catalyst containing platinum as a main component. It is an electrode and integrally bonded to one side of the diaphragm, and the thickness of the catalyst electrode is 100 angstroms to 500 angstroms.
【００２９】これにより、本発明になる電気化学式水素
センサは、ドリフトが少なく、また直線性精度が良好で
あるので、高濃度の水素濃度をも正確に測定できる。As a result, the electrochemical hydrogen sensor according to the present invention has little drift and good linearity accuracy, so that a high concentration of hydrogen can be measured accurately.
【００３０】その工業的利用価値は大きい。Its industrial utility value is great.
【図１】本発明にかかる電気化学式水素センサの断面構
造図である。FIG. 1 is a sectional structural view of an electrochemical hydrogen sensor according to the present invention.
１ 触媒電極 ２ 対極 ３ 電解液 ４ 隔膜 ５ Ｏ−リング ６ 容器本体 ７ 抵抗 ８ 集電体 １１ 接合体 DESCRIPTION OF SYMBOLS 1 catalyst electrode 2 counter electrode 3 electrolyte solution 4 diaphragm 5 O-ring 6 container body 7 resistance 8 current collector 11 bonded body
Claims (1)
水素透過性を有する隔膜とを備えてなる電気化学式水素
センサにおいて、 該作用極は、白金を主成分とする触媒電極であって、か
つ隔膜の片面に一体接合されており、 該触媒電極の厚さが１００から５００オングストローム
であることを特徴とする電気化学式水素センサ。1. A working electrode for electrochemically oxidizing hydrogen,
In an electrochemical hydrogen sensor comprising a hydrogen-permeable diaphragm, the working electrode is a catalyst electrode containing platinum as a main component, and is integrally joined to one side of the diaphragm, and the thickness of the catalyst electrode is An electrochemical hydrogen sensor having a size of 100 to 500 angstroms.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7319547A JPH09138215A (en) | 1995-11-14 | 1995-11-14 | Electrochemical hydrogen sensor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7319547A JPH09138215A (en) | 1995-11-14 | 1995-11-14 | Electrochemical hydrogen sensor |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH09138215A true JPH09138215A (en) | 1997-05-27 |
Family
ID=18111481
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP7319547A Pending JPH09138215A (en) | 1995-11-14 | 1995-11-14 | Electrochemical hydrogen sensor |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH09138215A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2006030027A (en) * | 2004-07-16 | 2006-02-02 | Dkk Toa Corp | Sensitivity restoring method of diaphragm type sensor, measuring instrument and electrode regeneration device |
| US7179354B2 (en) | 2002-05-21 | 2007-02-20 | Tanita Corporation | Electrochemical sensor |
-
1995
- 1995-11-14 JP JP7319547A patent/JPH09138215A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7179354B2 (en) | 2002-05-21 | 2007-02-20 | Tanita Corporation | Electrochemical sensor |
| JP2006030027A (en) * | 2004-07-16 | 2006-02-02 | Dkk Toa Corp | Sensitivity restoring method of diaphragm type sensor, measuring instrument and electrode regeneration device |
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