JPH04279853A - Gas sensor - Google Patents
Gas sensorInfo
- Publication number
- JPH04279853A JPH04279853A JP3068782A JP6878291A JPH04279853A JP H04279853 A JPH04279853 A JP H04279853A JP 3068782 A JP3068782 A JP 3068782A JP 6878291 A JP6878291 A JP 6878291A JP H04279853 A JPH04279853 A JP H04279853A
- Authority
- JP
- Japan
- Prior art keywords
- catalyst
- sno2
- added
- gas sensor
- gas
- 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
- 239000003054 catalyst Substances 0.000 claims abstract description 75
- XOLBLPGZBRYERU-UHFFFAOYSA-N tin dioxide Chemical compound O=[Sn]=O XOLBLPGZBRYERU-UHFFFAOYSA-N 0.000 claims abstract description 46
- 229910052697 platinum Inorganic materials 0.000 claims abstract description 11
- 229910052763 palladium Inorganic materials 0.000 claims abstract description 10
- 229910052703 rhodium Inorganic materials 0.000 claims abstract description 10
- 229910052741 iridium Inorganic materials 0.000 claims abstract description 9
- 239000002131 composite material Substances 0.000 claims description 28
- 239000011248 coating agent Substances 0.000 claims 1
- 238000000576 coating method Methods 0.000 claims 1
- 230000035945 sensitivity Effects 0.000 abstract description 13
- 229910002835 Pt–Ir Inorganic materials 0.000 abstract description 5
- 230000003197 catalytic effect Effects 0.000 abstract description 4
- 150000001875 compounds Chemical class 0.000 abstract 3
- 230000003247 decreasing effect Effects 0.000 abstract 1
- 230000001590 oxidative effect Effects 0.000 abstract 1
- 239000007789 gas Substances 0.000 description 28
- KDLHZDBZIXYQEI-UHFFFAOYSA-N palladium Substances [Pd] KDLHZDBZIXYQEI-UHFFFAOYSA-N 0.000 description 24
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 18
- 230000003647 oxidation Effects 0.000 description 15
- 238000007254 oxidation reaction Methods 0.000 description 15
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 13
- 239000000203 mixture Substances 0.000 description 8
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Substances [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 7
- 239000010948 rhodium Substances 0.000 description 7
- 229910018967 Pt—Rh Inorganic materials 0.000 description 6
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 5
- 238000001514 detection method Methods 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 2
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 2
- 239000002253 acid Substances 0.000 description 2
- 239000001257 hydrogen Substances 0.000 description 2
- 229910052739 hydrogen Inorganic materials 0.000 description 2
- NNPPMTNAJDCUHE-UHFFFAOYSA-N isobutane Chemical compound CC(C)C NNPPMTNAJDCUHE-UHFFFAOYSA-N 0.000 description 2
- 239000011259 mixed solution Substances 0.000 description 2
- 239000000758 substrate Substances 0.000 description 2
- DANYXEHCMQHDNX-UHFFFAOYSA-K trichloroiridium Chemical compound Cl[Ir](Cl)Cl DANYXEHCMQHDNX-UHFFFAOYSA-K 0.000 description 2
- 230000010718 Oxidation Activity Effects 0.000 description 1
- 229910021627 Tin(IV) chloride Inorganic materials 0.000 description 1
- 238000002441 X-ray diffraction Methods 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 229910002065 alloy metal Inorganic materials 0.000 description 1
- 229910021529 ammonia Inorganic materials 0.000 description 1
- 230000002301 combined effect Effects 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 description 1
- 229910052737 gold Inorganic materials 0.000 description 1
- 239000010931 gold Substances 0.000 description 1
- 239000001282 iso-butane Substances 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- PIBWKRNGBLPSSY-UHFFFAOYSA-L palladium(II) chloride Chemical compound Cl[Pd]Cl PIBWKRNGBLPSSY-UHFFFAOYSA-L 0.000 description 1
- 239000010970 precious metal Substances 0.000 description 1
- SONJTKJMTWTJCT-UHFFFAOYSA-K rhodium(iii) chloride Chemical compound [Cl-].[Cl-].[Cl-].[Rh+3] SONJTKJMTWTJCT-UHFFFAOYSA-K 0.000 description 1
- 238000001179 sorption measurement Methods 0.000 description 1
- 238000005979 thermal decomposition reaction Methods 0.000 description 1
- QHGNHLZPVBIIPX-UHFFFAOYSA-N tin(II) oxide Inorganic materials [Sn]=O QHGNHLZPVBIIPX-UHFFFAOYSA-N 0.000 description 1
- HPGGPRDJHPYFRM-UHFFFAOYSA-J tin(iv) chloride Chemical compound Cl[Sn](Cl)(Cl)Cl HPGGPRDJHPYFRM-UHFFFAOYSA-J 0.000 description 1
- 150000004684 trihydrates Chemical class 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Landscapes
- Investigating Or Analyzing Materials By The Use Of Fluid Adsorption Or Reactions (AREA)
- Investigating Or Analyzing Materials By The Use Of Electric Means (AREA)
Abstract
Description
【0001】0001
【発明の利用分野】この発明はSnO2系ガスセンサに
関し、特にその湿度依存性の抑制に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a SnO2 gas sensor, and particularly to suppressing its humidity dependence.
【0002】0002
【従来技術】SnO2に貴金属触媒を加えたガスセンサ
は周知である。また相対感度の調整のため、SnO2か
らなるガス感応体の表面を、酸化触媒層で被覆したガス
センサも周知である。SnO2系ガスセンサには、周知
のように出力に湿度依存性があるとの問題がある。発明
者はこの問題について検討し、湿度依存性の小さな触媒
材料の開発に成功し、この触媒を用いることによりSn
O2系ガスセンサの湿度依存性の抑制に成功した。2. Description of the Related Art A gas sensor in which a precious metal catalyst is added to SnO2 is well known. Furthermore, in order to adjust the relative sensitivity, a gas sensor in which the surface of a gas sensitive body made of SnO2 is coated with an oxidation catalyst layer is also well known. As is well known, SnO2-based gas sensors have a problem in that their output is dependent on humidity. The inventor studied this problem and succeeded in developing a catalyst material with low humidity dependence, and by using this catalyst, Sn
We succeeded in suppressing the humidity dependence of O2-based gas sensors.
【0003】0003
【発明の課題】この発明の課題は、SnO2系ガスセン
サの湿度依存性を減少させることにある。SUMMARY OF THE INVENTION An object of the present invention is to reduce the humidity dependence of a SnO2-based gas sensor.
【0004】0004
【発明の構成】この発明は、触媒として、Pt,Pd,
Rhからなる群の少なくとも一員の元素を用いたSnO
2系ガスセンサにおいて、前記の触媒を、Pt,Pd,
Rhからなる群の少なくとも一員の元素と、Ir元素と
の複合触媒としたことを特徴とする。Ir含有のこの触
媒(Pt,Pd,RhのいずれかとIrとの複合触媒)
は、SnO2に添加しても良く、あるいはSnO2ガス
感応体を被覆する酸化触媒層に用いても良い。またこの
触媒は、SnO2をアルミナ等の骨材に分散させる場合
、骨材に添加しても良い。Ir系のこの触媒は活性の湿
度依存性が小さく、センサの湿度依存性の内で触媒活性
に起因する部分を減少させる。Irは任意の含有量で湿
度依存性を減少させるが、Pt,Pd,Rh,Ir中の
Ir含有量の好ましい範囲は原子比で0.1〜0.5で
あり、この範囲で湿度依存性が特に減少する。Irを用
いた複合触媒には金やRe等の第3成分を添加しても良
く、その場合のIr濃度はPt,Pd,Rh,Ir中の
Ir含有量を基に定め、金等の第3成分は無視する。こ
れはIrとPt等との複合作用が重要だからである。な
お単味のIr自体の触媒活性は低い。Ir系のこの触媒
の存在状態は主としてPt−Ir等の合金金属であるが
、これに限るものではなく例えば複合酸化物として存在
するものでも良い。発明者はPt−Ir触媒のX線回折
を介して、複合触媒が合金として存在することを確認し
た。[Structure of the Invention] This invention uses Pt, Pd,
SnO using at least one member of the group consisting of Rh
In the two-system gas sensor, the catalyst is Pt, Pd,
The present invention is characterized in that it is a composite catalyst of at least one member of the group consisting of Rh and an Ir element. This Ir-containing catalyst (composite catalyst of Pt, Pd, Rh and Ir)
may be added to SnO2, or may be used in the oxidation catalyst layer covering the SnO2 gas receptor. This catalyst may also be added to aggregates when SnO2 is dispersed in aggregates such as alumina. This Ir-based catalyst has a low humidity dependence of activity, reducing the portion of the sensor's humidity dependence that is attributable to catalytic activity. Ir reduces humidity dependence at any content, but the preferred range of Ir content in Pt, Pd, Rh, and Ir is 0.1 to 0.5 in terms of atomic ratio; particularly decreases. A third component such as gold or Re may be added to a composite catalyst using Ir. In that case, the Ir concentration is determined based on the Ir content in Pt, Pd, Rh, and Ir. Ignore the three components. This is because the combined effect of Ir, Pt, etc. is important. Note that the catalytic activity of simple Ir itself is low. The state of existence of this Ir-based catalyst is mainly an alloy metal such as Pt-Ir, but it is not limited to this, and may exist as a composite oxide, for example. The inventor confirmed that the composite catalyst exists as an alloy through X-ray diffraction of the Pt-Ir catalyst.
【0005】[0005]
【発明の効果】この発明では、SnO2系ガスセンサの
湿度依存性を抑制することができる。According to the present invention, the humidity dependence of the SnO2 gas sensor can be suppressed.
【0006】[0006]
【実施例】図1に、実施例のガスセンサの構造を示す。
図において、2はアルミナ等の基板で、図示しないヒー
タを内蔵している。4はSnO2ガス感応体層で、Sn
O2に、IrとPt,Pd,Rhからなる群の少なくと
も一員の元素との複合触媒を添加したものである。なお
以下、この複合触媒をIr複合触媒という。6は酸化触
媒層で、エタノール等のガスを燃焼させ、メタンやイソ
ブタン等への相対感度を向上させるためのものである。
酸化触媒層6にもIr複合触媒を添加する。8,8はガ
ス感応体層4に接続した一対の電極である。[Embodiment] FIG. 1 shows the structure of a gas sensor according to an embodiment. In the figure, 2 is a substrate made of alumina or the like, which has a built-in heater (not shown). 4 is a SnO2 gas sensitive layer;
A composite catalyst of Ir and at least one member of the group consisting of Pt, Pd, and Rh is added to O2. Note that this composite catalyst will hereinafter be referred to as an Ir composite catalyst. 6 is an oxidation catalyst layer for burning gas such as ethanol and improving relative sensitivity to methane, isobutane, etc. An Ir composite catalyst is also added to the oxidation catalyst layer 6. Reference numerals 8 and 8 denote a pair of electrodes connected to the gas sensitive layer 4.
【0007】酸化触媒層6は設けなくても良い。このよ
うな例を図2に示す。またIr複合触媒は、酸化触媒層
6にのみ添加しても良い。このような例を図3に示す。
図において、14は単味のPdを添加したSnO2ガス
感応体層である。[0007] The oxidation catalyst layer 6 may not be provided. Such an example is shown in FIG. Further, the Ir composite catalyst may be added only to the oxidation catalyst layer 6. Such an example is shown in FIG. In the figure, 14 is a SnO2 gas sensitive layer to which plain Pd is added.
【0008】図1〜図3のガスセンサの製造条件を示す
。SnCl4をアンモニアで加水分解し、得られたSn
酸ゾルを700℃で熱分解してSnO2とした。このS
nO2に塩化イリディウムと塩化パラディウムの混合溶
液を加え、乾燥後に650℃で熱分解した。熱分解後に
200℃で水素還元し、Pd−Ir複合触媒を担持した
SnO2を得た。酸化触媒層6の担体としてγ−アルミ
ナ(比表面積100m2/gr)を用い、塩化白金酸と
塩化ロディウムの3水塩の混合溶液に塩化イリディウム
を加えたものを含浸させて、乾燥後に650℃で熱分解
し、150℃で水素還元した。Ir複合触媒添加後のS
nO2やγ−アルミナをペースト化し、SnO2を基板
2に印刷して650℃で焼成し、SnO2ガス感応体層
4を得た(膜厚10μm)。ついでγ−アルミナを印刷
し、650℃で焼成して酸化触媒層6を積層した(膜厚
20μm)。The manufacturing conditions of the gas sensor shown in FIGS. 1 to 3 are shown. SnCl4 was hydrolyzed with ammonia and the obtained Sn
The acid sol was thermally decomposed at 700°C to form SnO2. This S
A mixed solution of iridium chloride and palladium chloride was added to nO2, and after drying, it was thermally decomposed at 650°C. After thermal decomposition, hydrogen reduction was performed at 200°C to obtain SnO2 supporting a Pd-Ir composite catalyst. γ-alumina (specific surface area 100 m2/gr) was used as a support for the oxidation catalyst layer 6, impregnated with a mixed solution of trihydrate of chloroplatinic acid and rhodium chloride to which iridium chloride was added, and dried at 650°C. It was thermally decomposed and reduced with hydrogen at 150°C. S after adding Ir composite catalyst
A paste of nO2 and γ-alumina was formed, SnO2 was printed on the substrate 2, and the paste was baked at 650°C to obtain a SnO2 gas sensitive layer 4 (thickness: 10 μm). Then, γ-alumina was printed and fired at 650° C. to form an oxidation catalyst layer 6 (film thickness: 20 μm).
【0009】得られたガスセンサの湿度依存性を評価し
た。結果を表1〜表3に示す。測定雰囲気には、20℃
の乾燥空気と20℃で水蒸気圧20Torrの加湿雰囲
気とを用いた。図1のセンサを用いた表1はメタン検出
用のデータを示しり、図2のセンサを用いた表2はエタ
ノール検出用のデータを示し、図3のセンサを用いた表
3はメタン検出用のデータを示す。The humidity dependence of the obtained gas sensor was evaluated. The results are shown in Tables 1 to 3. The measurement atmosphere is 20℃
dry air and a humidified atmosphere at 20° C. and a water vapor pressure of 20 Torr. Table 1 using the sensor in Figure 1 shows data for methane detection, Table 2 using the sensor in Figure 2 shows data for ethanol detection, and Table 3 using the sensor in Figure 3 shows data for methane detection. The following data is shown.
【0010】0010
【表1】湿度依存性
(ガス感応体層,酸化触媒層ともIr系複合触媒を添加
)
触 媒 組 成 Pd 100
Pd 72 Pd 65 Pd 55
Pd 0(感応体4に添加) Ir 0
Ir 28 Ir 35 Ir
45 Ir 100 感 度
CH4 1000ppm Dry 7.4
7.6 7.8 7.
4 5.6 〃 Wet
10.0 8.7 8
.6 8.3 7.2Rsdry
/Rswet 1.21
1.15 1.10 1.12
1.28CH4 5000ppm Dry
12.2 12.6 13.0
12.6 8.3 〃
Wet 14.5 14.2
14.2 14.0 10
.0Rsdry/Rswet 1.
19 1.13 1.09
1.11 1.21ETOH 1000ppm
Dry 9.6 9.5
9.7 10.1 12.5
〃 Wet 13.0
11.9 12.0 12.8
18.1Rsdry/Rswet
1.35 1.25 1.24
1.27 1.45* 感度は各雰
囲気での抵抗値と20℃の清浄乾燥空気での抵抗値との
比,触媒はSnO2ガス感応体4に添加し、添加量は触
媒合計量とSnとの原子比で0.7Atom%に固定し
、Pd/Irの原子比を制御、触媒組成はPd/Irの
割合をAtom%単位で表示,酸化触媒層6にはアルミ
ナ中のAl原子との原子比で0.5Atom%のPt−
Rh−Ir複合触媒を添加、触媒組成は原子比でPt5
0:Rh25:Ir25%、センサ温度は400℃、E
TOHはエタノールを表す。[Table 1] Humidity dependence (Ir-based composite catalyst is added to both gas sensitive layer and oxidation catalyst layer) Catalyst Composition Pd 100
Pd 72 Pd 65 Pd 55
Pd 0 (added to sensitive body 4) Ir 0
Ir 28 Ir 35 Ir
45 Ir 100 Sensitivity CH4 1000ppm Dry 7.4
7.6 7.8 7.
4 5.6 Wet
10.0 8.7 8
.. 6 8.3 7.2 Rsdry
/Rswet 1.21
1.15 1.10 1.12
1.28CH4 5000ppm Dry
12.2 12.6 13.0
12.6 8.3 〃
Wet 14.5 14.2
14.2 14.0 10
.. 0Rsdry/Rswet 1.
19 1.13 1.09
1.11 1.21ETOH 1000ppm
Dry 9.6 9.5
9.7 10.1 12.5
〃Wet 13.0
11.9 12.0 12.8
18.1Rsdry/Rswet
1.35 1.25 1.24
1.27 1.45* Sensitivity is the ratio of the resistance value in each atmosphere and the resistance value in clean dry air at 20°C.The catalyst is added to the SnO2 gas sensitive body 4, and the amount added is determined by the total amount of catalyst and Sn. The atomic ratio of Pd/Ir is fixed at 0.7Atom%, and the atomic ratio of Pd/Ir is controlled.The catalyst composition shows the Pd/Ir ratio in Atom%. 0.5Atom% Pt-
Added Rh-Ir composite catalyst, catalyst composition is Pt5 in atomic ratio
0:Rh25:Ir25%, sensor temperature 400℃, E
TOH stands for ethanol.
【0011】[0011]
【表2】湿度依存性
(ガス感応体層にIr系複合触媒を添加)触 媒
組 成 Pd 100 Pd 72
Pd 65 Pd 55 Pd
0(感応体4に添加) Ir 0 Ir
28 Ir 35 Ir 45
Ir 100 感 度
ETOH 1000ppm Dry 18.2
17.1 17.0 16.
7 21 〃 Wet
34 26 25
26 36 Rsdry/
Rswet 1.85 1
.53 1.47 1.56
1.73ETOH 5000ppm Dry
35 34 33
31 34 〃
Wet 55 46
44 44 55 R
sdry/Rswet 1.57
1.36 1.34 1.4
2 1.61* 感度は各雰囲気での抵抗値と
20℃の清浄乾燥空気での抵抗値との比,触媒はSnO
2ガス感応体4に添加し、添加量は触媒合計量とSnと
の原子比で0.7Atom%に固定し、Pd/Irの原
子比を制御、触媒組成はPd/Irの割合をAtom%
単位で表示,センサ温度は300℃。[Table 2] Humidity dependence (Ir-based composite catalyst added to gas sensitive layer) Catalyst
Composition Pd 100 Pd 72
Pd 65 Pd 55 Pd
0 (added to sensitive body 4) Ir 0 Ir
28 Ir 35 Ir 45
Ir 100 Sensitivity ETOH 1000ppm Dry 18.2
17.1 17.0 16.
7 21 Wet
34 26 25
26 36 Rsdry/
Rswet 1.85 1
.. 53 1.47 1.56
1.73ETOH 5000ppm Dry
35 34 33
31 34 〃
Wet 55 46
44 44 55 R
sdry/Rswet 1.57
1.36 1.34 1.4
2 1.61* Sensitivity is the ratio of the resistance value in each atmosphere to the resistance value in clean dry air at 20°C.The catalyst is SnO
The amount of addition is fixed at 0.7 Atom% in terms of the atomic ratio between the total amount of catalyst and Sn, the atomic ratio of Pd/Ir is controlled, and the catalyst composition is determined by changing the ratio of Pd/Ir to Atom%.
Displayed in units, sensor temperature is 300℃.
【0012】0012
【表3】湿度依存性
(酸化触媒層にIr系複合触媒を添加)触 媒 組
成 Pt−Rh 100 Pt−Rh
85 Pt−Rh 75 Pt−Rh 55 P
t−Rh 0(感応体4に添加) Ir
0 Ir 15 Ir 25
Ir 45 Ir 100 感 度
CH4 1000ppm Dry 7.6
7.5 7.4
7.3 5.2 〃
Wet 11.0 9.9
10.0 8.6
7.9Rsdry/Rswet
1.45 1.32 1.2
1 1.18 1.52
CH4 5000ppm Dry 12.
5 12.4 12.2
12.1 7.8 〃
Wet 17.3 15
.6 14.5 13.9
11.5Rsdry/Rswet
1.38 1.26 1
.19 1.15 1.47ET
OH 1000ppm Dry 10.4
9.8 9.6
9.5 17.5 〃
Wet 17.1 13.5
13.0 12.5 30
Rsdry/Rswet 1
.64 1.38 1.35
1.32 1.72* 感度は各雰
囲気での抵抗値と20℃の清浄乾燥空気での抵抗値との
比,Ir複合触媒は酸化触媒層6に添加し、添加量は触
媒合計量とAlとの原子比で0.5Atom%に固定し
、Pt−Rh成分とIr成分の原子比を制御,Pt−R
h成分の組成は原子比でPt2:Rh1、センサ温度は
400℃、ETOHはエタノールを表す。[Table 3] Humidity dependence (Ir-based composite catalyst added to oxidation catalyst layer) Catalyst Composition Pt-Rh 100 Pt-Rh
85 Pt-Rh 75 Pt-Rh 55 P
t-Rh 0 (added to sensitive body 4) Ir
0 Ir 15 Ir 25
Ir 45 Ir 100 Sensitivity
CH4 1000ppm Dry 7.6
7.5 7.4
7.3 5.2 〃
Wet 11.0 9.9
10.0 8.6
7.9Rsdry/Rswet
1.45 1.32 1.2
1 1.18 1.52
CH4 5000ppm Dry 12.
5 12.4 12.2
12.1 7.8 〃
Wet 17.3 15
.. 6 14.5 13.9
11.5Rsdry/Rswet
1.38 1.26 1
.. 19 1.15 1.47ET
OH 1000ppm Dry 10.4
9.8 9.6
9.5 17.5 〃
Wet 17.1 13.5
13.0 12.5 30
Rsdry/Rswet 1
.. 64 1.38 1.35
1.32 1.72* Sensitivity is the ratio of the resistance value in each atmosphere and the resistance value in clean dry air at 20°C, the Ir composite catalyst is added to the oxidation catalyst layer 6, and the amount added is the total amount of catalyst and Al The atomic ratio of Pt-Rh component and Ir component was fixed at 0.5Atom%, and the atomic ratio of Pt-Rh component and Ir component was controlled.
The composition of component h is Pt2:Rh1 in atomic ratio, the sensor temperature is 400°C, and ETOH represents ethanol.
【0013】表3の酸化触媒層6の触媒組成をIr10
0%とした試料では、エタノール感度が高い。これは単
味のIrの酸化活性が低く、エタノールの除去が不十分
であることを示している。従って単味のIr触媒は酸化
触媒層6の材料としては不適である。また表1のガス感
応体層4に単味のIrを加えた試料でも、メタン感度が
低く、エタノール感度が高い。これも同様に単味のIr
の触媒活性が低く、メタンの吸着の促進が不十分で、エ
タノールの除去も不十分であることを示している。従っ
て単味のIr触媒はガス感応体層4の材料としても不適
である。これに対してPd−Ir,Pt−Rh−Ir等
のIr系複合触媒は、センサの湿度依存性が小さく、か
つ相対感度やガス濃度依存性は単味のPd触媒やIr無
添加のPt−Pd触媒と遜色のない結果が得られる。The catalyst composition of the oxidation catalyst layer 6 in Table 3 is Ir10.
The sample with 0% had high ethanol sensitivity. This indicates that the oxidation activity of simple Ir is low and that ethanol removal is insufficient. Therefore, a simple Ir catalyst is not suitable as a material for the oxidation catalyst layer 6. Further, even in the sample in which simple Ir was added to the gas sensitive layer 4 in Table 1, the methane sensitivity was low and the ethanol sensitivity was high. This is also a simple Ir
This indicates that the catalytic activity of the catalyst is low, the promotion of methane adsorption is insufficient, and the removal of ethanol is also insufficient. Therefore, a single Ir catalyst is not suitable as a material for the gas sensitive layer 4. On the other hand, Ir-based composite catalysts such as Pd-Ir and Pt-Rh-Ir have small humidity dependence of the sensor, and relative sensitivity and gas concentration dependence are small compared to plain Pd catalysts and Pt-Rh-Ir-free catalysts. Results comparable to Pd catalysts can be obtained.
【0014】ここではSnO2ガス感応体4にはPd−
Ir複合触媒を用いたが、Pt−Ir複合触媒やRh−
Ir複合触媒、あるいはPt−Rh−Ir複合触媒でも
良い。また酸化触媒層6にはPt−Rh−Ir複合触媒
を用いたが、Pd−Ir複合触媒やPt−Ir複合触媒
、Rh−Ir複合触媒でも良い。Here, the SnO2 gas sensitive body 4 contains Pd-
Although an Ir composite catalyst was used, Pt-Ir composite catalyst or Rh-
An Ir composite catalyst or a Pt-Rh-Ir composite catalyst may be used. Further, although a Pt-Rh-Ir composite catalyst is used for the oxidation catalyst layer 6, a Pd-Ir composite catalyst, a Pt-Ir composite catalyst, or a Rh-Ir composite catalyst may be used.
【図1】実施例のガスセンサの断面図である。FIG. 1 is a sectional view of a gas sensor according to an example.
【図2】実施例のガスセンサの断面図である。FIG. 2 is a sectional view of the gas sensor of the example.
【図3】実施例のガスセンサの断面図である。FIG. 3 is a cross-sectional view of the gas sensor of the example.
2 基板 4 SnO2層 6 酸化触媒層 8 電極 14 SnO2層 2 Board 4 SnO2 layer 6 Oxidation catalyst layer 8 Electrode 14 SnO2 layer
Claims (2)
る群の少なくとも一員の元素を用いたSnO2系ガスセ
ンサにおいて、前記の触媒を、Pt,Pd,Rhからな
る群の少なくとも一員の元素と、Ir元素との複合触媒
としたことを特徴とする、ガスセンサ。1. A SnO2-based gas sensor using at least one member of the group consisting of Pt, Pd, and Rh as a catalyst, wherein the catalyst is composed of at least one element of the group consisting of Pt, Pd, and Rh, and Ir. A gas sensor characterized by a composite catalyst with elements.
少なくとも一員の元素とIr元素との複合触媒により、
SnO2ガス感応体表面を被覆したことを特徴とする、
請求項1に記載のガスセンサ。2. A composite catalyst of at least one member of the group consisting of Pt, Pd, and Rh and an Ir element,
characterized by coating the surface of the SnO2 gas sensitive body,
The gas sensor according to claim 1.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
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JP3068782A JP2980290B2 (en) | 1991-03-08 | 1991-03-08 | Gas detection method and gas sensor used therefor |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP3068782A JP2980290B2 (en) | 1991-03-08 | 1991-03-08 | Gas detection method and gas sensor used therefor |
Publications (2)
Publication Number | Publication Date |
---|---|
JPH04279853A true JPH04279853A (en) | 1992-10-05 |
JP2980290B2 JP2980290B2 (en) | 1999-11-22 |
Family
ID=13383647
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Application Number | Title | Priority Date | Filing Date |
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JP3068782A Expired - Fee Related JP2980290B2 (en) | 1991-03-08 | 1991-03-08 | Gas detection method and gas sensor used therefor |
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JP (1) | JP2980290B2 (en) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6319473B1 (en) | 1998-06-16 | 2001-11-20 | Figaro Engineering, Inc. | Co sensor and its fabrication |
WO2009130884A1 (en) * | 2008-04-22 | 2009-10-29 | 日本特殊陶業株式会社 | Gas sensor |
JP2010002335A (en) * | 2008-06-20 | 2010-01-07 | New Cosmos Electric Corp | Gas detection element |
Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS5999343A (en) * | 1982-11-30 | 1984-06-08 | Toshiba Corp | Gas detecting element |
JPS5999342A (en) * | 1982-11-30 | 1984-06-08 | Toshiba Corp | Gas detecting element |
-
1991
- 1991-03-08 JP JP3068782A patent/JP2980290B2/en not_active Expired - Fee Related
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS5999343A (en) * | 1982-11-30 | 1984-06-08 | Toshiba Corp | Gas detecting element |
JPS5999342A (en) * | 1982-11-30 | 1984-06-08 | Toshiba Corp | Gas detecting element |
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6319473B1 (en) | 1998-06-16 | 2001-11-20 | Figaro Engineering, Inc. | Co sensor and its fabrication |
KR100582505B1 (en) * | 1998-06-16 | 2006-05-23 | 휘가로기켄 가부시키가이샤 | Co sensor and its fabrication |
WO2009130884A1 (en) * | 2008-04-22 | 2009-10-29 | 日本特殊陶業株式会社 | Gas sensor |
JP4921556B2 (en) * | 2008-04-22 | 2012-04-25 | 日本特殊陶業株式会社 | Gas sensor |
JP2010002335A (en) * | 2008-06-20 | 2010-01-07 | New Cosmos Electric Corp | Gas detection element |
Also Published As
Publication number | Publication date |
---|---|
JP2980290B2 (en) | 1999-11-22 |
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