JPH0438310B2 - - Google Patents

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Publication number
JPH0438310B2
JPH0438310B2 JP60207772A JP20777285A JPH0438310B2 JP H0438310 B2 JPH0438310 B2 JP H0438310B2 JP 60207772 A JP60207772 A JP 60207772A JP 20777285 A JP20777285 A JP 20777285A JP H0438310 B2 JPH0438310 B2 JP H0438310B2
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JP
Japan
Prior art keywords
sensor
zno
gas
mol
znal
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 - Lifetime
Application number
JP60207772A
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Japanese (ja)
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JPS6269157A (en
Priority date (The priority date 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 date listed.)
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Priority to JP20777285A priority Critical patent/JPS6269157A/en
Publication of JPS6269157A publication Critical patent/JPS6269157A/en
Publication of JPH0438310B2 publication Critical patent/JPH0438310B2/ja
Granted legal-status Critical Current

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Description

【発明の詳細な説明】[Detailed description of the invention]

〔産業上の利用分野〕 この発明は毒性ガスである硫化水素を検知する
硫化水素選択検知用センサにかかるものである。 〔従来の技術〕 硫化水素(H2S)は、化学プラントの諸工程で
用いられており、天然にも下水道や火山地帯で発
生しているきわめて有毒なガスであり、その許容
濃度は10ppmと定められている。労働安全衛生法
ではH2Sの検知測定法として、吸光光度法、ガス
クロマトグラフ法および検知管法が定められてい
る。 吸光光度法はH2Sを亜鉛アミン溶液に吸収させ
たのち、試薬を加えて生成発色するメチレンブル
ーの濃度を分光光度計で測定するもので、複雑な
分析装置であり、操作も繁雑で高価でもある。ガ
スクロマトグラフ法も同様である。検知管法は安
価で簡便ではあるが連続監視測定には不向きであ
る。また、定電位電解式のセンサも一部で使用さ
れているが隔膜電極と電解液(硫酸水溶液など)
を使用しているためセンサ寿命が短く、メンテナ
ンスに手数がかかる。 以上のように、H2S漏洩の連続監視の手段は未
だ非常に不充分であり、また、工場内の雑ガス
(有機溶剤など)による誤報も問題となるため、
H2Sに対する選択性を有し、経時安定な、簡便な
センサが求められている。 〔発明が解決しようとする問題点〕 上記の要望に応えるために、従来ガスセンサ材
料として知られているSnO2、ZnOを用いて試作
したところ、SnO2系センサでは第3図のように
水素(H2)、アルコール(C2H5OH)、アセチレ
ン(C2H2)などの方がH2Sより感度は高く、
H2S選択性は得られなかつた。ZnOに0.01%程度
の微量のGaを添加した薄膜タイプのセンサにお
いて第4図のようなH2S選択性が得られた。しか
しこのセンサではアルコールに対する選択性が未
だ十分とはいえず、また、NOxやO3の影響を受
けやすいという問題点があつた。 なお、ZnOはメタン、プロパンなどの可燃性ガ
ス検知用のガスセンサ材料として知られており、
ZnO粉体にGa2O3、In2O3、SnO2などの異種の酸
化物を混合して焼結するガスセンサも提案されて
いるが(特開昭55−136947号公報、特開昭55−
12449号公報、特開昭54−104392〜7号公報な
ど)、これらはそれぞれの単独酸化物の混合物で
あつて、スピネル構造の複合酸化物を形成せぬよ
う留意されており、また、Pt、Pdなどの貴金属
触媒を添加して増感したもので、メタン、プロパ
ン等を対象としたガスセンサであり、H2Sに対す
る選択性は見出されていない。 この発明は上記H2S選択検知用センサの改良に
係るものであり、非常に高感度で高選択性の長期
安定な、ソリツドタイプのH2S選択検知用センサ
を提供することを目的とするものである。 〔問題点を解決するための手段〕 この発明にかかる硫化水素選択検知用センサ
は、ZnOを主材とし、これにZnAl2O4
ZnFe2O4、ZnGa2O4、ZnCr2O4、ZnIn2O4のスピ
ネル型複合酸化物のうち少なくとも1種を含有さ
せたものである。 〔作 用〕 この発明においては、感ガス半導体であるZnO
にスピネル型複合酸化物ZnAl2O4、ZnFe2O4
ZnGa2O4、ZnCr2O4、ZnIn2O4などが共存してい
ることにより、アルコールやNOxに対する感度
が抑制されH2Sに対して非常に高い感度の選択性
を有する。 〔実施例〕 以下この発明の実施例について説明する。 実施例 1 (共沈法) 硝酸亜鉛または塩化亜鉛の20%水溶液に硝酸ア
ルミニウムを5モル%混入し、これに28%アンモ
ニア水を滴下して中和して白色沈殿を得る。この
沈殿を水洗し、120゜で24hr乾燥ののち1100゜と1hr
焼成すると、ZnOとZnAl2O4の混合物微粉が得ら
れる(X線回折により確認)、この粉体を、コロ
イダルアルミナをバインダとして水粘りし、この
ペーストを第1図aのように電極付アルミナ基板
1上に厚さ約0.1mmに塗布、乾燥後800℃/hr焼結
して、酸化物焼結層4を形成する。なお、2は
Pt膜電極、3はPt膜ヒータである。 第2図にこのセンサの特性を示す。アルコー
ル、NOxに対する感度が第4図にくらべ顕著に
抑制されていることがわかる。 センサ構造は第1図bのようにPt線コイル5
に球状に酸化物焼結層4を形成したものでも良
く、また、第1図cのように円筒状のアルミナ基
板1A、コイルヒータ3A、円環状のPt膜電極
2等を用いてもよく、種々の変形が可能である。 上記粉体の調整法としては、ZnOとAl2O3微粉
を混合したものを1000℃以上で焼成しても同様の
特性が得られた。また、ZnO粉末に硝酸アルミニ
ウムを含浸して乾燥後高温で焼成する(含浸法)
などの方法も可能である。 実施例 2 (スパツタ法) ZnOにGa2O310モル%添加した粉末プレス焼結
円板をターゲツトとして第1図dのようなPt膜
電極2の形成された電極付アルミナ基板1上に
1μm厚さに薄膜4Aをスパツタ法を用いて形成す
る。 次いで、1100℃で1時間熱処理を施す。この場
合も第1表に示すように良好な特性を示す。
[Industrial Application Field] The present invention relates to a hydrogen sulfide selective detection sensor that detects hydrogen sulfide, which is a toxic gas. [Prior art] Hydrogen sulfide (H 2 S) is an extremely toxic gas that is used in various processes in chemical plants and is also generated naturally in sewers and volcanic areas, and its permissible concentration is 10 ppm. It is determined. The Industrial Safety and Health Act stipulates the absorption photometry method, gas chromatography method, and detection tube method as H 2 S detection and measurement methods. In the spectrophotometric method, H 2 S is absorbed into a zinc amine solution, then a reagent is added and the concentration of methylene blue, which is produced and colored, is measured using a spectrophotometer.It is a complex analytical device that is difficult to operate and expensive. be. The same applies to gas chromatography. Although the detector tube method is cheap and simple, it is not suitable for continuous monitoring measurements. In addition, constant potential electrolysis type sensors are also used in some cases, but they require a diaphragm electrode and an electrolyte (such as a sulfuric acid aqueous solution).
The sensor life is short and maintenance is troublesome. As mentioned above, the means for continuous monitoring of H 2 S leaks is still very insufficient, and false alarms caused by miscellaneous gases (organic solvents, etc.) in the factory are also a problem.
There is a need for a simple sensor that is selective to H 2 S and is stable over time. [Problems to be solved by the invention] In order to meet the above-mentioned demands, we fabricated a prototype using SnO 2 and ZnO, which are conventionally known as gas sensor materials.As shown in Fig. H 2 ), alcohol (C 2 H 5 OH), acetylene (C 2 H 2 ), etc. have higher sensitivity than H 2 S.
No H 2 S selectivity was obtained. The H 2 S selectivity shown in Fig. 4 was obtained in a thin film type sensor made by adding a small amount of Ga of about 0.01% to ZnO. However, this sensor still has the problem of not having sufficient selectivity for alcohol and being susceptible to the effects of NO x and O 3 . Furthermore, ZnO is known as a gas sensor material for detecting flammable gases such as methane and propane.
Gas sensors have also been proposed in which ZnO powder is mixed with different oxides such as Ga 2 O 3 , In 2 O 3 , SnO 2 and sintered (Japanese Unexamined Patent Application Publication No. 136947/1983, −
12449, JP-A-54-104392-7, etc.), these are mixtures of individual oxides, and care has been taken not to form a composite oxide with a spinel structure. It is a gas sensor that has been sensitized by adding a noble metal catalyst such as Pd, and is intended for methane, propane, etc., and selectivity for H 2 S has not been found. This invention relates to an improvement of the above H 2 S selection detection sensor, and an object thereof is to provide a solid type H 2 S selection detection sensor that is extremely sensitive, highly selective, and stable over a long period of time. It is. [Means for Solving the Problems] The hydrogen sulfide selective detection sensor according to the present invention has ZnO as its main material, and ZnAl 2 O 4 , ZnAl 2 O 4 ,
It contains at least one kind of spinel type composite oxides such as ZnFe 2 O 4 , ZnGa 2 O 4 , ZnCr 2 O 4 , and ZnIn 2 O 4 . [Function] In this invention, ZnO, which is a gas-sensitive semiconductor,
spinel type composite oxides ZnAl 2 O 4 , ZnFe 2 O 4 ,
Due to the coexistence of ZnGa 2 O 4 , ZnCr 2 O 4 , ZnIn 2 O 4 , etc., the sensitivity to alcohol and NO x is suppressed, and the sensitivity to H 2 S is extremely high. [Examples] Examples of the present invention will be described below. Example 1 (Co-precipitation method) 5 mol% of aluminum nitrate is mixed into a 20% aqueous solution of zinc nitrate or zinc chloride, and 28% aqueous ammonia is added dropwise to neutralize the mixture to obtain a white precipitate. This precipitate was washed with water, dried at 120° for 24 hours, and then dried at 1100° for 1 hour.
When fired, a fine powder mixture of ZnO and ZnAl 2 O 4 is obtained (confirmed by X-ray diffraction). This powder is made sticky with water using colloidal alumina as a binder, and the paste is made into alumina with electrodes as shown in Figure 1 a. It is applied onto the substrate 1 to a thickness of about 0.1 mm, dried and then sintered at 800° C./hr to form the sintered oxide layer 4. Furthermore, 2 is
A Pt film electrode and 3 are a Pt film heater. Figure 2 shows the characteristics of this sensor. It can be seen that the sensitivity to alcohol and NO x is significantly suppressed compared to Fig. 4. The sensor structure consists of a Pt wire coil 5 as shown in Figure 1b.
The oxide sintered layer 4 may be formed in a spherical shape, or a cylindrical alumina substrate 1A, a coil heater 3A, an annular Pt film electrode 2, etc. may be used as shown in FIG. Various modifications are possible. As for the method for preparing the above powder, similar characteristics were obtained even when a mixture of ZnO and Al 2 O 3 fine powder was fired at 1000°C or higher. In addition, ZnO powder is impregnated with aluminum nitrate, dried and then fired at high temperature (impregnation method).
Other methods are also possible. Example 2 (Sputtering method) A powder press sintered disk containing 10 mol% of Ga 2 O 3 added to ZnO was used as a target on an electrode-attached alumina substrate 1 on which a Pt film electrode 2 was formed as shown in Fig. 1d.
A thin film 4A having a thickness of 1 μm is formed using a sputtering method. Next, heat treatment is performed at 1100°C for 1 hour. This case also shows good characteristics as shown in Table 1.

〔発明の効果〕〔Effect of the invention〕

この発明は以上説明したとおり、感ガス半導体
ZnOを主材とし、これに、ZnAl2O4、ZnFe2O4
ZnGa2O4、ZnCr2O4、ZnIn2O4のスピネル型複合
酸化物のうち少なくとも1種を1モル%以上10モ
ル%以下を含有せしめたので、H2Sを選択的に、
非常に高感度で、かつ、長期安定な硫化水素選択
検知用センサを得ることができる。しかも、ソリ
ツドタイプであるので、従来のようにH2Sの検知
測定法に比較して取扱いがきわめて容易である利
点がある。
As explained above, this invention is a gas-sensitive semiconductor.
ZnO is the main material, and ZnAl 2 O 4 , ZnFe 2 O 4 ,
Since at least one of the spinel type composite oxides of ZnGa 2 O 4 , ZnCr 2 O 4 , and ZnIn 2 O 4 is contained in an amount of 1 mol % or more and 10 mol % or less, H 2 S is selectively
A highly sensitive and long-term stable hydrogen sulfide selective detection sensor can be obtained. Furthermore, since it is a solid type, it has the advantage of being extremely easy to handle compared to conventional H 2 S detection and measurement methods.

【図面の簡単な説明】[Brief explanation of drawings]

第1図a〜dはこの発明の実施例をそれぞれ示
す断面図、第2図は第1図aの実施例の各種ガス
に対するガス濃度とセンサ出力との関係を示す
図、第3図は従来のSnO2系センサの各種ガスの
ガス濃度とセンサ出力との関係を示す図、第4図
はZnOに微量のGaを添付した場合の各種ガスの
ガス濃度とセンサ出力との関係を示す図である。 図中、1は電極付アルミナ基板、2はPt膜電
極、3はPt膜ヒータ、4は酸化物焼結層である。
Figures 1a to d are cross-sectional views showing embodiments of the present invention, Figure 2 is a diagram showing the relationship between gas concentration and sensor output for various gases in the embodiment of Figure 1a, and Figure 3 is a diagram showing the relationship between the sensor output and the conventional example. Fig . 4 is a diagram showing the relationship between the gas concentration of various gases and the sensor output when a small amount of Ga is attached to ZnO. be. In the figure, 1 is an alumina substrate with an electrode, 2 is a Pt film electrode, 3 is a Pt film heater, and 4 is an oxide sintered layer.

Claims (1)

【特許請求の範囲】[Claims] 1 感ガス半導体ZnOを主材とし、これに、
ZnAl2O4、ZnFe2O4、ZnGa2O4、ZnCr2O4
ZnIn2O4のスピネル型複合酸化物のうち少なくと
も1種を1モル%以上10モル%以下を含有せしめ
たことを特徴とする硫化水素選択検知用センサ。
1 The main material is gas-sensitive semiconductor ZnO, and
ZnAl 2 O 4 , ZnFe 2 O 4 , ZnGa 2 O 4 , ZnCr 2 O 4 ,
A sensor for selectively detecting hydrogen sulfide, characterized in that it contains at least one type of spinel-type composite oxide of ZnIn 2 O 4 in an amount of 1 mol % or more and 10 mol % or less.
JP20777285A 1985-09-21 1985-09-21 Hydrogen sulfide selective sensor Granted JPS6269157A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP20777285A JPS6269157A (en) 1985-09-21 1985-09-21 Hydrogen sulfide selective sensor

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP20777285A JPS6269157A (en) 1985-09-21 1985-09-21 Hydrogen sulfide selective sensor

Publications (2)

Publication Number Publication Date
JPS6269157A JPS6269157A (en) 1987-03-30
JPH0438310B2 true JPH0438310B2 (en) 1992-06-24

Family

ID=16545270

Family Applications (1)

Application Number Title Priority Date Filing Date
JP20777285A Granted JPS6269157A (en) 1985-09-21 1985-09-21 Hydrogen sulfide selective sensor

Country Status (1)

Country Link
JP (1) JPS6269157A (en)

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP3823520B2 (en) 1998-03-11 2006-09-20 日産化学工業株式会社 Anhydrous zinc antimonate semiconductor gas sensor and method for manufacturing the same
JP2009519470A (en) * 2005-12-12 2009-05-14 ネクステック、マテリアルズ、リミテッド Ceramic H2S sensor
CN102866189B (en) * 2012-08-26 2014-03-19 吉林大学 NASICON-based H2S sensor using composite metallic oxide as sensitive electrode
CN104749225B (en) * 2015-04-22 2017-07-18 吉林大学 ZnO/ZnFe2O4Composite sensitive material, preparation method and the application in acetone gas sensor
CN109490376A (en) * 2018-12-03 2019-03-19 安徽工业大学 A kind of graphene-ZnGa that PARA FORMALDEHYDE PRILLS(91,95) gas is highly selective2O4Composite air-sensitive material

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS55129741A (en) * 1979-03-30 1980-10-07 Anritsu Corp Detector for external atmosphere
JPS58122453A (en) * 1982-01-18 1983-07-21 Chichibu Cement Co Ltd Gas sensor element

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS55129741A (en) * 1979-03-30 1980-10-07 Anritsu Corp Detector for external atmosphere
JPS58122453A (en) * 1982-01-18 1983-07-21 Chichibu Cement Co Ltd Gas sensor element

Also Published As

Publication number Publication date
JPS6269157A (en) 1987-03-30

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