JPS60100752A - Gas sensor - Google Patents
Gas sensorInfo
- Publication number
- JPS60100752A JPS60100752A JP20956883A JP20956883A JPS60100752A JP S60100752 A JPS60100752 A JP S60100752A JP 20956883 A JP20956883 A JP 20956883A JP 20956883 A JP20956883 A JP 20956883A JP S60100752 A JPS60100752 A JP S60100752A
- Authority
- JP
- Japan
- Prior art keywords
- gas sensor
- sno2
- vanadium
- vanadium oxide
- sensitivity
- Prior art date
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Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
- G01N27/02—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance
- G01N27/04—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance
- G01N27/12—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance of a solid body in dependence upon absorption of a fluid; of a solid body in dependence upon reaction with a fluid, for detecting components in the fluid
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- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- Physics & Mathematics (AREA)
- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Analytical Chemistry (AREA)
- Biochemistry (AREA)
- General Health & Medical Sciences (AREA)
- General Physics & Mathematics (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Investigating Or Analyzing Materials By The Use Of Fluid Adsorption Or Reactions (AREA)
Abstract
Description
【発明の詳細な説明】
この発明は、Ｓｎ ０２をガス感応材料とするガスセン
サの改良に関スル。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a gas sensor using Sn 02 as a gas-sensitive material.
この明細書では、バナジウム酸化物の添加量を金属バナ
ジウムに換算して示し、かつＳｎ０２１ｇ当り１μｇの
添加を１ ｐｐｍと、ｔｏ−ｙの添加を１％として表示
する。In this specification, the amount of vanadium oxide added is expressed in terms of metal vanadium, and the addition of 1 μg per 1 g of Sn02 is expressed as 1 ppm, and the addition of to-y is expressed as 1%.
Ｓｎ ０２を用いたガスセンサが実用化されている。Gas sensors using Sn02 have been put into practical use.
このガスセンサバ、Ｈ２やアルコール（例ｔばエタノー
ル）への感度が経時的に増すという欠点が有る。This gas sensor has the disadvantage that its sensitivity to H2 and alcohol (for example, ethanol) increases over time.
この発明は、Ｓｎ ０２を用いたガスセンサの、Ｈ２や
アルコールへの感度を安定化することを目的とし、その
ため少量のバナジウム酸化物を添加する。The purpose of this invention is to stabilize the sensitivity of a gas sensor using Sn 02 to H2 and alcohol, and for that purpose, a small amount of vanadium oxide is added.
バナジウム酸化物の添加による経時変化の防止は、５ｎ
０２に対してのみ有効で、他のガス感応材料、例えばＩ
ｎ２０３やＺｎＯでは効果が得られない。Prevention of aging by adding vanadium oxide is 5n
02 and other gas-sensitive materials, such as I
No effect can be obtained with n203 or ZnO.
まだＳｎ ０２に、バナジウム以外の酸化物、例えば５
ｂ２０３、Ｎｂ２Ｏ５、Ｔａ２０５、を添力０しても効
果は得られない。バナジウム酸化物の添加は５０ｐｐｍ
の添加でも大きな効果を持つが、１％以上添加するとガ
スセンサの抵抗値が増しかつ感度が低下する。従って添
加量は４ ｏ ｐｐｍ−１％の範囲に限られる。Still in Sn02, oxides other than vanadium, e.g.
No effect can be obtained even if the addition of b203, Nb2O5, Ta205 is 0. Addition of vanadium oxide is 50 ppm
Although the addition of 1% or more has a large effect, the resistance value of the gas sensor increases and the sensitivity decreases. Therefore, the amount added is limited to 40 ppm-1%.
以下に実施例を説明する。Examples will be described below.
［ガスセンサの構造］
実施例で用いたガスセンサの構造を第１図に示す。この
ガスセンサ（２）は、アルミナ等の絶縁管（４）にＳｎ
０２ガス感応膜（６）を塗布後焼結したもので、一対
の電極（８）、（ｌＯ）を介してＳｎ ０２ガス感応膜
（６）の抵抗値を検出する。そして絶縁管（４）にはヒ
ータ（１２）を挿入し、ガスセンサ（２）を必要な温度
に加熱する。[Structure of Gas Sensor] The structure of the gas sensor used in the examples is shown in FIG. This gas sensor (2) is made of an insulating tube (4) made of alumina etc.
The Sn 02 gas sensitive film (6) is applied and sintered, and the resistance value of the Sn 02 gas sensitive film (6) is detected through a pair of electrodes (8) and (lO). A heater (12) is then inserted into the insulating tube (4) to heat the gas sensor (2) to a required temperature.
ガスセンサ（２）の構造は、自由に変形できる。例えば
第１図において電極＋８１ 、００１を廃止し、ヒータ
（１２１と５ｎ０２ガス感応膜（６）との並列抵抗の抵
抗値を検出するようにしても良い。そのためには、ヒー
タ（１ｚを絶縁管（４）の外周に沿って巻き回せば良い
。The structure of the gas sensor (2) can be freely modified. For example, in Fig. 1, the electrodes +81 and 001 may be omitted and the resistance value of the parallel resistance between the heater (121 and the 5n02 gas sensitive film (6)) may be detected. All you have to do is wind it around the outer periphery of (4).
［５ｎ０２の調整］
５ｎＣＮ４水溶液をＮＨ３で中和し、水洗を繰り返して
スズ酸ゾルとする。このゾルを７５０℃で２時間空気中
で加熱し、Ｓｎ ０２を得る。金属バナジウムを硝酸に
溶解させ、塩化パラジウム水溶液と混合した後に、Ｓｎ
０２に含浸させる。これを６５０℃ＶｔＣ５０分間空
気中で加熱し、バナジウム酸化物とパラジウムとを担持
したＳｎ ０２を得る。[Adjustment of 5n02] A 5nCN4 aqueous solution is neutralized with NH3 and washed with water repeatedly to obtain a stannic acid sol. This sol is heated at 750° C. for 2 hours in air to obtain Sn 02. After dissolving metal vanadium in nitric acid and mixing it with an aqueous palladium chloride solution, Sn
Impregnated with 02. This is heated in air at 650° C.VtC for 50 minutes to obtain Sn 02 carrying vanadium oxide and palladium.
バナジウムは、主としてＶ２Ｏ５として５ｎ０２に担持
される。しかしＶ２Ｏ５は還元され易い物質であり、実
際にはＶ２Ｏ５の他に微量のｖ２ ｏ４等を含むと考え
られる。そして実施例では、バナジウムの添加量を５ｏ
ｐｐｍ、４００ ｐｐｍ、 ７００ ｐｐｍ、０．１％
、０．３％、０．７％の６種について検討した。Vanadium is supported on 5n02 primarily as V2O5. However, V2O5 is a substance that is easily reduced, and in reality, it is thought that in addition to V2O5, trace amounts of V2O4 and the like are included. In the example, the amount of vanadium added was 50
ppm, 400 ppm, 700 ppm, 0.1%
, 0.3%, and 0.7%.
また従来例としてバナジウム無添加のものを、比較例と
してバナジウムを１．５％添加のものを検討した。なお
バナジウム酸化物は、Ｓｎ ０２への不純物としては希
れで、不純物としての存在量は１ ｐｐｍ以下である。Further, as a conventional example, a product without vanadium added was investigated, and as a comparative example, a product with 1.5% vanadium added was investigated. Note that vanadium oxide is a rare impurity to Sn 02, and the amount present as an impurity is 1 ppm or less.
さらに、パラジウムはガスへの感度と応答速度とを改善
するため加えたもので、その添加量は金属パラジウム換
算で５ｎｕ２１ ｇ当り３、、ｙである。Furthermore, palladium was added to improve the sensitivity to gas and the response speed, and the amount added was 3.,y per 5 nu21 g in terms of metal palladium.
〔測定法］
測定には、２５°Ｃで相対湿度６５％の雰囲気を用い、
また各ガスの濃度を２０００ ｐｐｍとする。[Measurement method] For measurement, an atmosphere of 25°C and 65% relative humidity was used.
Further, the concentration of each gas is set to 2000 ppm.
結果は、５個のガスセンサｔ２） Ｋ対する平均値を示
す。The results show the average value for five gas sensors t2) K.
〔経時特性］
バナジウム無添力０のガスセンサ（２）を、４００°Ｃ
に１２０日間空気中で通電した際の経時特性を第２回置
に示す。ガスセンサ（２）の抵抗値（Ｒｓ）は、エタノ
ールや水素雰囲気下で減少し、これらのガスへの感度が
増大してゆく。この現象は、Ｓｎ ０２の調整法や添加
物の種類によらず一般的に生ずる。[Aging characteristics] The gas sensor (2) with zero vanadium additive was heated at 400°C.
The characteristics over time when electricity was applied in the air for 120 days are shown in the second picture. The resistance value (Rs) of the gas sensor (2) decreases in an ethanol or hydrogen atmosphere, and the sensitivity to these gases increases. This phenomenon generally occurs regardless of the method of preparing Sn 02 or the type of additive.
エタノールやＨ２への経時変化の原因は不明で、ガスセ
ンサ（２）の加熱温度とともに経時変化が著しくなるこ
とがわかっている。The cause of the change over time to ethanol and H2 is unknown, but it is known that the change over time becomes more significant as the heating temperature of the gas sensor (2) increases.
バナジウム酸化物をｉｏｏｏｐｐｍ添加したガスセンサ
（２）への、同じ条件での経時特性を第２図（Ｂ）に示
す。エタノールやＨ２への高感度化は防止嘔れ、ガスセ
ンサ（２）の抵抗値（Ｒｓ）や、各ガスへの感度は変化
しない。Figure 2 (B) shows the aging characteristics of the gas sensor (2) to which ioooppm of vanadium oxide was added under the same conditions. High sensitivity to ethanol and H2 is prevented, and the resistance value (Rs) of the gas sensor (2) and sensitivity to each gas do not change.
第３図に、バナジウム酸化物の添加量の影響を示す。図
は４００℃で１２０日間空気中に通電した際のエタノー
ルやＨ２への抵抗値の変化を示し、最初の抵抗値（Ｒｓ
ｏ）と１２０日後の抵抗値（Ｒｓｆ）の比を縦軸とする
。バナジウム酸化物の添加効果は、５０ ｐｐｍの添加
でも著しく、１０００ ｐｐｍ付近から飽和する。FIG. 3 shows the influence of the amount of vanadium oxide added. The figure shows the change in resistance to ethanol and H2 when electricity is applied in air at 400℃ for 120 days, and the initial resistance value (Rs
The vertical axis is the ratio of resistance value (Rsf) after 120 days. The effect of adding vanadium oxide is significant even at 50 ppm, and saturates from around 1000 ppm.
バナジウム酸化物の効果は、Ｓｎ ０２との組み合せで
のみ生じ、Ｉｎ２０ＢやＺｎＯには効果がない。The effect of vanadium oxide occurs only in combination with Sn02, and has no effect on In20B or ZnO.
まだバナジウム酸化物に代えて、Ｎｂ２ｏ５やＴａ２０
５．５ｂ２ｏ３をＳｎ ０２ に加えても、経時変化は
抑制されない。バナジウム酸化物の効果は、添加方法と
は無関係で、例えばｖ２ ｏ５の粉末を５ｎ０２粉末と
混合して担持させても良い。５ｎ０２には種々の添加物
、例えば実施例で用いたパラジウム、あるいは焼結剤と
してのシリカゾノペを加えても良く、Ａｊｌ’２０ａや
石英等の骨材を加えても良い。バナジウム酸化物の影響
は、Ｓｎ ０２への添加物や混合物とは無関係である。Still, instead of vanadium oxide, Nb2o5 or Ta20
Even if 5.5b2o3 is added to Sn 02 , the change over time is not suppressed. The effect of vanadium oxide is independent of the method of addition; for example, v2 o5 powder may be mixed with 5n02 powder and supported. Various additives may be added to 5n02, such as palladium used in the examples, or silica zonope as a sintering agent, and aggregates such as Ajl'20a and quartz may be added. The effect of vanadium oxide is independent of additives and mixtures to Sn02.
つぎに、バナジウム酸化物により経時変化が防止される
原因は、不明である。第１に、Ｓｎ ０２がエタノール
やＨ２に対して経時変化する原因が不明である。第２に
、バナジウム酸化物との組み合せのみが有効である原因
も不明である。Next, the reason why vanadium oxide prevents changes over time is unknown. First, the reason why Sn 02 changes over time with respect to ethanol and H2 is unknown. Secondly, the reason why only the combination with vanadium oxide is effective is also unknown.
［ガス感度］
第４装置に、バナジウム酸化物を１．０００１）Ｉ）ｍ
添加したガスセンサ（２）の、製造直後の抵抗値（Ｒｓ
）と各ガスへの感度を示す。結果は、バナジウム酸化
物無添加のものと、はとんど同一である。[Gas Sensitivity] Vanadium oxide was added to the fourth device at 1.0001)I)m
The resistance value (Rs
) and the sensitivity to each gas. The results are almost identical to those without the addition of vanadium oxide.
第４図（Ｂ）に、バナジウム酸化物を１．５％添加した
ものの、特性を示す。バナジウム酸化物の大量添加によ
り、ガスセンサ（２）の抵抗値（Ｒｓ）が増し、ガスへ
の感度も減少することがわかる。FIG. 4(B) shows the characteristics of a sample to which 1.5% of vanadium oxide was added. It can be seen that by adding a large amount of vanadium oxide, the resistance value (Rs) of the gas sensor (2) increases and the sensitivity to gas also decreases.
第５図に、バナジウム酸化物の添加量による、抵抗値（
Ｒｓ）とガスへの感度（空気中とガス中との抵抗値の比
）とを示す。１０００ ｐｐｍ以上のバナジウム酸化物
の添加で、ガスセンサ（２）は高抵抗化し、感度も低下
する。そしてこの効果は、添加量１％を境に著しく増大
する。従って、バナジウム酸化物の添加量は１％以下と
することが必要で、好ましくは０．４％以下とする。Figure 5 shows the resistance value (
Rs) and sensitivity to gas (ratio of resistance values in air and gas). Addition of 1000 ppm or more of vanadium oxide increases the resistance of the gas sensor (2) and lowers its sensitivity. This effect increases significantly when the addition amount reaches 1%. Therefore, the amount of vanadium oxide added must be 1% or less, preferably 0.4% or less.
バナジウムは主として５価で存在し、原子価制御理論か
らすれば、ＳｎＯ２はバナジウムの添加により低抵抗化
するはずである。しかし得られた結果は、予想と一致し
ない。Vanadium mainly exists in a pentavalent state, and according to valence control theory, the resistance of SnO2 should be lowered by adding vanadium. However, the results obtained do not match expectations.
この発明では、５ｎ０２に少量のバナジウム酸化物を添
加することにより、感度を損うことなく、アルコールや
水素への経時変化を防止できる。In this invention, by adding a small amount of vanadium oxide to 5n02, it is possible to prevent changes over time to alcohol and hydrogen without impairing sensitivity.
第１図は実施例のガスセンサの部分切り欠き図で、第２
図（５）、（Ｂ）〜第５図はガスセンサの特性図である
。
第１図
第２ 図（Ａ）
一−＠ −−ａｉｒ −Ｏ−ＩＳ
ｏ ２０ ４０ ６０ ８０ １００ １２０Ｔｉｍｅ
（ｄａｄ）
第２ 図（Ｂ）
−・−ａｉｒ−ｏ−ＩＢ
Ｔｉｍのａｙ）
第３図
第４ 図（Ａ）
第４ 図（Ｂ）
２５０ ３００ ３５０ ４００ ４５０ ５００ Ｔ
ｓ（’Ｃ）第５図
ト
（ｋFig. 1 is a partially cutaway diagram of the gas sensor of the embodiment;
Figures (5) and (B) to Figure 5 are characteristic diagrams of the gas sensor. Figure 1 Figure 2 (A) 1-@ --air -O-IS o 20 40 60 80 100 120Time
(dad) Fig. 2 (B) -・-air-o-IB Tim's ay) Fig. 3 Fig. 4 (A) Fig. 4 (B) 250 300 350 400 450 500 T
s('C) Figure 5 t(k
Claims (1)
において、 ５ｎ ０２には、バナジウムの酸化物を、ＳｎＯ２１ｇ
当り金属バナジウム換算で４０μｇ〜１０招１添加した
ことを特徴とするガスセンサ。[Claims] [In a gas sensor that utilizes a change in the resistance value of 11Sn02, 5n02 contains vanadium oxide, SnO21g
A gas sensor characterized in that 40 μg to 10 μg of vanadium is added in terms of metal vanadium.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP20956883A JPS60100752A (en) | 1983-11-08 | 1983-11-08 | Gas sensor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP20956883A JPS60100752A (en) | 1983-11-08 | 1983-11-08 | Gas sensor |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS60100752A true JPS60100752A (en) | 1985-06-04 |
| JPH0226184B2 JPH0226184B2 (en) | 1990-06-07 |
Family
ID=16574982
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP20956883A Granted JPS60100752A (en) | 1983-11-08 | 1983-11-08 | Gas sensor |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS60100752A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0206236A2 (en) * | 1985-06-24 | 1986-12-30 | Figaro Engineering Inc. | Gas sensor |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5736812A (en) * | 1980-08-15 | 1982-02-27 | Tokyo Shibaura Electric Co | KANSHITSUSOSHI |
-
1983
- 1983-11-08 JP JP20956883A patent/JPS60100752A/en active Granted
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5736812A (en) * | 1980-08-15 | 1982-02-27 | Tokyo Shibaura Electric Co | KANSHITSUSOSHI |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0206236A2 (en) * | 1985-06-24 | 1986-12-30 | Figaro Engineering Inc. | Gas sensor |
| US4731226A (en) * | 1985-06-24 | 1988-03-15 | Figaro Engineering Inc. | Gas sensor |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0226184B2 (en) | 1990-06-07 |
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