JPH0322584B2 - - Google Patents
Info
- Publication number
- JPH0322584B2 JPH0322584B2 JP18017383A JP18017383A JPH0322584B2 JP H0322584 B2 JPH0322584 B2 JP H0322584B2 JP 18017383 A JP18017383 A JP 18017383A JP 18017383 A JP18017383 A JP 18017383A JP H0322584 B2 JPH0322584 B2 JP H0322584B2
- Authority
- JP
- Japan
- Prior art keywords
- gas
- catalyst
- sensitive
- sensitive element
- sensitivity
- 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
Links
- 239000003054 catalyst Substances 0.000 claims description 47
- 239000004065 semiconductor Substances 0.000 claims description 21
- 238000004519 manufacturing process Methods 0.000 claims description 11
- 239000000758 substrate Substances 0.000 claims description 8
- 238000010304 firing Methods 0.000 claims description 7
- 229910052763 palladium Inorganic materials 0.000 claims description 7
- 229910052697 platinum Inorganic materials 0.000 claims description 7
- 229910018072 Al 2 O 3 Inorganic materials 0.000 claims description 6
- 229910004298 SiO 2 Inorganic materials 0.000 claims description 6
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 claims description 5
- 239000002994 raw material Substances 0.000 claims description 4
- 239000002002 slurry Substances 0.000 claims description 4
- 239000007789 gas Substances 0.000 description 58
- 230000035945 sensitivity Effects 0.000 description 18
- 238000000034 method Methods 0.000 description 7
- 230000007774 longterm Effects 0.000 description 4
- -1 SiO 2 Chemical class 0.000 description 3
- GEIAQOFPUVMAGM-UHFFFAOYSA-N ZrO Inorganic materials [Zr]=O GEIAQOFPUVMAGM-UHFFFAOYSA-N 0.000 description 3
- 238000007084 catalytic combustion reaction Methods 0.000 description 3
- 150000001805 chlorine compounds Chemical class 0.000 description 3
- 230000007423 decrease Effects 0.000 description 3
- 238000001514 detection method Methods 0.000 description 3
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- 229910006404 SnO 2 Inorganic materials 0.000 description 2
- MCMNRKCIXSYSNV-UHFFFAOYSA-N Zirconium dioxide Chemical compound O=[Zr]=O MCMNRKCIXSYSNV-UHFFFAOYSA-N 0.000 description 2
- 230000032683 aging Effects 0.000 description 2
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 2
- 239000000567 combustion gas Substances 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 230000001747 exhibiting effect Effects 0.000 description 2
- NNPPMTNAJDCUHE-UHFFFAOYSA-N isobutane Chemical compound CC(C)C NNPPMTNAJDCUHE-UHFFFAOYSA-N 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 229910052863 mullite Inorganic materials 0.000 description 2
- 239000000843 powder Substances 0.000 description 2
- 239000002904 solvent Substances 0.000 description 2
- 230000002378 acidificating effect Effects 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 238000009413 insulation Methods 0.000 description 1
- 239000001282 iso-butane Substances 0.000 description 1
- WABPQHHGFIMREM-UHFFFAOYSA-N lead(0) Chemical compound [Pb] WABPQHHGFIMREM-UHFFFAOYSA-N 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 230000001590 oxidative effect Effects 0.000 description 1
- 239000011148 porous material Substances 0.000 description 1
- 238000010298 pulverizing process Methods 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
- 230000002123 temporal effect Effects 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
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
Landscapes
- 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)
Description
［発明の技術分野］
本発明は感ガス素子の製造方法に係り、特に感
度及び選択性に優れた半導体式の感ガス素子の製
造方法に関する。
［発明の技術分野的背景とその問題点］
従来感ガス素子として接触燃焼式や半導体式の
感ガス素子がよく知られている。
この内、接触燃焼式のものは、Ptなどのフイ
ラメント線が燃焼ガス（検出ガス）により高温と
なり、この時のフイラメント線の電気抵抗を測定
することにより、燃焼ガスを検出するというもの
である。しかしながらこのような接触燃焼式によ
るものでは、高温条件下において長時間フイラメ
ントが加熱されるため、フイラメント線表面か
ら、金属が蒸発し、フイラメント線の電気抵抗が
増加するなど、検出精度を落とす原因となつてい
た。そこで上記欠点を改良するために前記フイラ
メント線をアルミナ、シリカ等の耐熱酸化物中に
埋設し、さらに前記耐熱性酸化物表面に酸化用触
媒としてのPt、Pdを設ける如き構造の感ガス素
子も開発されているが、検出ガスの選択性が悪い
こと、感度が低いこと、長期の使用に対する安定
性が充分でないことなどの欠点を有していた。
また半導体式の感ガス素子は酸化物半導体表面
にガスが接触すると、酸化物半導体の表面の非抵
抗が変化する事を利用したものである。例えばＮ
型半導性を示すZnO、SnO2、Fe2O3等に還元性ガ
スが接触すると、抵抗値は減少し、また酸化性ガ
スが接触すると抵抗値は増加する。またＰ型半導
性を示す酸化物半導体においては抵抗値の増減が
逆の関係となる。上記の如き酸化物半導体におい
て、各種ガスと反応制すなわち選択性は半導体表
面温度、表面電子レベルの構造、気孔率及び気孔
の大きさ等により決まるが、一般には酸化物半導
体のみでは感ガス素子として感度が小さく、選択
性にも乏しいものであつた。そこで酸化物半導体
に触媒を添加含有せしめ感度を上げる事が試みら
れているが、以下の如く欠点を有していた。つま
り主成分である酸化物半導体と触媒とは、それぞ
れ最適の焼成温度が異なるため、両者の特徴を充
分発揮する焼成温度をつかむ事がきわめて難しか
つた。さらに製造工程における焼成段階あるいは
感ガス素子として高温条件下で使用する際（感ガ
ス素子は感度を上げるため内部ヒーターを設け、
酸化物半導体表面を数百℃に保つて使用する事が
好ましい）、触媒が酸化物半導体中に固溶し、感
度の低下、経時変化の増大などの要因となつてい
た。
［発明の目的］
本発明は以上の点を考慮してなされたもので、
感度及びガスの選択性に優れ、かつ長時間の使用
による経時変化の少ない半導体式の感ガス素子を
提供する事を目的とする。
［発明の概要］
本発明は、絶縁性基体表面に一対の電極をもつ
て形成された酸化物半導体からなるガス感応体層
上に、Pt又はPdの塩化物を含む触媒と、Al2O3、
SiO2及びZrO2から選ばれた少なくとも一種から
成る担体を少なくとも含みスラリー化された触媒
原料を塗布焼成して触媒層を形成することを特徴
とする感ガス素子の製造方法である。
つまり本発明は、ZnO系、SnO2系、Fe2O3系等
の酸化物半導体からなるガス感応体層と、触媒層
とを分離して設け、触媒層の形成方法として、
Pt又はPdの塩化物を含む触媒と、Al2O3、SiO2
及びZrO2から選ばれた少なくとも一種から成る
担体を少なくとも含みスラリー化された触媒原料
を塗布焼成するという製法を用いることにより、
触媒を均一に分散し、担体に均一に保持させるこ
とができるため、長時間の使用に際しても触媒の
ガス感応体への拡散を防止することにより感ガス
素子としての経時変化を抑制し、また感度を著し
く向上させるものである。
本発明では、水等の適当の溶媒でスラリー化し
た触媒原料をガス感応体層上に塗布し、その後焼
成して触媒層を形成する。一旦スラリー化するこ
とにより、均一な触媒層を形成することができ
る。
また、本発明においては触媒層として担体に触
媒を担持させることにより、さらに経時変化を抑
制している。
このように担体を備えた触媒層を用いた感ガス
素子の経時変化率が小さいのは次のような理由に
よるものと考えられる。
まず、ガス感応体と触媒層とを分離した２層構
造により、例えば触媒のPtCl2がガス感応体の中
に固溶しないため、触媒の能力の劣化が起らない
ためと考えられる、また、担体に触媒が担持され
ているため、触媒の粒成長が防止され、表面積の
大きい状態で維持されるためと考えられる。特に
耐熱性のあるシリカ・アルミナ系化合物、すなわ
ちSiO2、Al2O3及びZrO2などに担持されている
と、表面積の大きい状態で維持される効果は大で
ある。
またPt、Pdの塩化物は、Pt、Pd又はその酸化
物に比べ粒成長がおこりにくいため、このような
塩化物を触媒として用いるとさらに効果的であ
る。
また、本発明に係る感ガス素子では、使用目的
によりガス感応体、触媒層の組合せを適宜選択す
ることにより、選択性、感度などを容易に選択す
ることができるという製造上における大きな利点
を有する。
本発明により得られる感ガス素子は、例えば絶
縁性基体表面に形成された一対の電極と、前記電
極を被覆する如く設けられた酸化物半導体からな
るガス感応体層と、担体を備え前記ガス感応体層
を覆う如く設けられた触媒層と、前記ガス感応体
を加熱するヒーターとを具備した構成をとる。
このような構成をとることにより、経時変化特
性、選択感度に優れた感ガス素子が得られる。
以下本発明に係る感ガス素子を用いる際の構成
例を第１図に断面的に示す。円筒状の絶縁基体１
外表面に一対の電極２を有し、前記円筒状の絶縁
基体１及び電極２を被覆するようにZnO系酸化物
半導体から成るガス感応体層３が設けられてい
る。さらに前記ガス感応体層３表面には触媒層４
が設けられている。また前記のように構成された
感ガス素子は例えば第２図に斜視的に示す如くピ
ン足上に組立てられる。なお図中５はリード線
を、６は絶縁板を、７はヒーターを示す。ヒータ
ー７はガス感応体の感度を向上させるために設け
られたものであり、必要に応じ適宜脱着が可能と
なつている。ヒーター７を円筒状の絶縁基体１の
中空部に嵌挿することにより、ヒーター７からの
熱は円筒状絶縁基体１の中空部における空気層、
および絶縁記載１を介してガス感応体に伝達され
るためガス感応体の温度分布が均一となり、さら
に長時間高温条件下での使用に際してもガス感応
体層、触媒層はほとんど劣化しない。また、例え
ば平板状の絶縁基体を用い、基体を介して裏面に
形成されたヒーターにより加熱することによつて
も同様に均一な温度分布を得ることができること
はいうまでもない。
［発明の効果］
以上説明したように本発明によれば、感度およ
びガス選択性に優れ、かつ長時間の使用による経
時変化の少ない感ガス素子を得ることができる感
ガス素子の製造方法が提供される。
［発明の実施例］
本発明に係る感ガス素子は以下の如く製造され
る。
まず本発明に用いる触媒層の担体は例えば
SiO2とAl2O3とを重量比で２：３の割合で充分混
合した後、1000〜1800℃の安易で仮焼結しムライ
ト化合物とする。さらに前記ムライト化合物をた
とえば遊星ミル・ポツトミル等の粉砕機で粉砕
し、微粉末とする。次にこの微粉末を一定量秤量
し、H2PtCl6・6H2O等の溶液と混合し、マグネ
ツトスタチ等で粉砕し、300〜1100℃で焼成し、
さらに粉砕工程を施し触媒を得る。この触媒にお
いてはSiO2−Al2O3自身が酸性触媒であり、かつ
耐熱性を有しているため、触媒としての補助作用
と担体との両方の働きをする。そこでガス感応体
３として、例えばZnO系の酸化物半導体を、第１
図に示す如く一対の電極２を設けた絶縁基体１に
塗布し乾燥後焼成しガス感応体層を形成する。し
かる後先に述べた触媒を適当な溶媒を用いてスラ
リー化し、ガス感応体３表面に塗布乾燥し、さら
に300〜1000℃で焼成し触媒層を形成して感ガス
素子を得る。
前述のような方法で製造した本発明に係る実施
例について諸特性を測定し、比較例と併せて第１
表に示す。なお第１表中Roは空気中における抵
抗値を、Rgは0.2％ガス濃度中における抵抗値を
示す。またカツコ中はRo／Rgで表される感度を
示し、経時変化は1000時間通電後の抵抗値の変化
率を示す。
[Technical Field of the Invention] The present invention relates to a method for manufacturing a gas-sensitive element, and more particularly to a method for manufacturing a semiconductor-type gas-sensitive element with excellent sensitivity and selectivity. [Technical background of the invention and its problems] Catalytic combustion type and semiconductor type gas sensing elements are well known as conventional gas sensing elements. Among these, in the catalytic combustion type, a filament wire such as Pt becomes hot due to combustion gas (detection gas), and the combustion gas is detected by measuring the electrical resistance of the filament wire at this time. However, with this type of catalytic combustion method, the filament is heated for a long time under high temperature conditions, which causes metal to evaporate from the surface of the filament wire, increasing the electrical resistance of the filament wire and causing a drop in detection accuracy. I was getting used to it. Therefore, in order to improve the above-mentioned drawbacks, a gas-sensitive element with a structure in which the filament wire is embedded in a heat-resistant oxide such as alumina or silica, and Pt or Pd as an oxidation catalyst is provided on the surface of the heat-resistant oxide is also proposed. Although it has been developed, it has drawbacks such as poor selectivity of detection gas, low sensitivity, and insufficient stability for long-term use. Further, a semiconductor type gas-sensitive element utilizes the fact that when a gas comes into contact with the surface of an oxide semiconductor, the non-resistance of the surface of the oxide semiconductor changes. For example, N
When a reducing gas comes into contact with ZnO, SnO 2 , Fe 2 O 3 , etc., which exhibit type semiconductivity, the resistance value decreases, and when an oxidizing gas comes into contact with it, the resistance value increases. In addition, in an oxide semiconductor exhibiting P-type semiconductivity, the relationship between increase and decrease in resistance is reversed. In the above-mentioned oxide semiconductors, the reaction rate with various gases, that is, the selectivity, is determined by the semiconductor surface temperature, surface electron level structure, porosity, pore size, etc., but in general, oxide semiconductors alone cannot be used as gas-sensitive elements. The sensitivity was low and the selectivity was poor. Therefore, attempts have been made to increase the sensitivity by adding a catalyst to the oxide semiconductor, but this method has the following drawbacks. In other words, the oxide semiconductor and catalyst, which are the main components, have different optimal firing temperatures, so it has been extremely difficult to find a firing temperature that fully brings out the characteristics of both. Furthermore, during the firing stage of the manufacturing process or when used as a gas-sensitive element under high-temperature conditions (gas-sensitive elements are equipped with an internal heater to increase sensitivity,
(It is preferable to maintain the surface of the oxide semiconductor at a temperature of several hundred degrees Celsius), the catalyst is dissolved in the oxide semiconductor, causing a decrease in sensitivity and an increase in changes over time. [Object of the invention] The present invention has been made in consideration of the above points, and
It is an object of the present invention to provide a semiconductor type gas-sensitive element that has excellent sensitivity and gas selectivity, and exhibits little change over time due to long-term use. [Summary of the Invention] The present invention provides a gas sensitive layer made of an oxide semiconductor formed with a pair of electrodes on the surface of an insulating substrate, a catalyst containing a chloride of Pt or Pd, and Al 2 O 3 . ,
This method of manufacturing a gas-sensitive element is characterized in that a catalyst layer is formed by applying and firing a slurry-formed catalyst raw material containing at least one carrier selected from SiO 2 and ZrO 2 . In other words, the present invention provides a method for forming a catalyst layer in which a gas sensitive layer made of an oxide semiconductor such as ZnO-based, SnO 2 -based, Fe 2 O 3 -based, etc. and a catalyst layer are provided separately.
Catalyst containing Pt or Pd chloride, Al 2 O 3 , SiO 2
By using a manufacturing method of coating and firing a slurry catalyst raw material containing at least one carrier selected from ZrO 2 and ZrO2,
Since the catalyst can be uniformly dispersed and held uniformly on the carrier, even during long-term use, it prevents the catalyst from diffusing into the gas-sensitive element, suppressing changes over time as a gas-sensitive element, and improving sensitivity. This significantly improves the In the present invention, a catalyst raw material made into a slurry with a suitable solvent such as water is applied onto a gas sensitive layer, and then fired to form a catalyst layer. Once slurried, a uniform catalyst layer can be formed. Further, in the present invention, by supporting a catalyst on a carrier as a catalyst layer, changes over time are further suppressed. The reason why the rate of change over time of a gas-sensitive element using a catalyst layer provided with a carrier is small is considered to be as follows. First, it is thought that due to the two-layer structure in which the gas sensitive body and the catalyst layer are separated, for example, PtCl 2 of the catalyst does not dissolve solidly in the gas sensitive body, so that the catalyst performance does not deteriorate. This is thought to be because the catalyst is supported on the carrier, which prevents grain growth of the catalyst and maintains a large surface area. In particular, when supported on heat-resistant silica-alumina compounds, such as SiO 2 , Al 2 O 3 and ZrO 2 , the effect of maintaining a large surface area is significant. Furthermore, since grain growth is less likely to occur in chlorides of Pt and Pd than in Pt, Pd, or their oxides, the use of such chlorides as catalysts is even more effective. Furthermore, the gas-sensitive element according to the present invention has a great manufacturing advantage in that selectivity, sensitivity, etc. can be easily selected by appropriately selecting the combination of the gas-sensitive body and the catalyst layer depending on the purpose of use. . The gas-sensitive element obtained by the present invention includes, for example, a pair of electrodes formed on the surface of an insulating substrate, a gas-sensitive layer made of an oxide semiconductor provided to cover the electrodes, and a carrier. The structure includes a catalyst layer provided to cover the body layer and a heater that heats the gas sensitive body. By adopting such a configuration, a gas-sensitive element having excellent aging characteristics and selective sensitivity can be obtained. An example of the configuration when using the gas-sensitive element according to the present invention is shown in cross section in FIG. Cylindrical insulating base 1
A gas sensitive layer 3 made of a ZnO-based oxide semiconductor is provided to cover the cylindrical insulating substrate 1 and the electrodes 2, and has a pair of electrodes 2 on the outer surface. Furthermore, a catalyst layer 4 is provided on the surface of the gas sensitive layer 3.
is provided. Further, the gas-sensitive element constructed as described above is assembled on a pin leg, for example, as shown perspectively in FIG. In the figure, 5 indicates a lead wire, 6 indicates an insulating plate, and 7 indicates a heater. The heater 7 is provided to improve the sensitivity of the gas sensitive element, and can be attached and detached as needed. By inserting the heater 7 into the hollow part of the cylindrical insulating base 1, the heat from the heater 7 is transferred to an air layer in the hollow part of the cylindrical insulating base 1.
Since the temperature is transmitted to the gas sensitive body through insulation description 1, the temperature distribution of the gas sensitive body becomes uniform, and the gas sensitive body layer and catalyst layer hardly deteriorate even when used under high temperature conditions for a long time. It goes without saying that a uniform temperature distribution can also be obtained by using, for example, a flat insulating substrate and heating it with a heater formed on the back surface of the substrate through the substrate. [Effects of the Invention] As explained above, the present invention provides a method for manufacturing a gas-sensitive element that can obtain a gas-sensitive element that has excellent sensitivity and gas selectivity and that exhibits little change over time due to long-term use. be done. [Embodiments of the Invention] A gas-sensitive element according to the present invention is manufactured as follows. First, the carrier of the catalyst layer used in the present invention is, for example,
After sufficiently mixing SiO 2 and Al 2 O 3 at a weight ratio of 2:3, the mixture is briefly sintered at 1000 to 1800°C to form a mullite compound. Further, the mullite compound is ground into a fine powder using a grinder such as a planetary mill or a pot mill. Next, a certain amount of this fine powder is weighed, mixed with a solution such as H 2 PtCl 6 6H 2 O, crushed with a magnetostat, etc., and calcined at 300 to 1100°C.
A further pulverization step is performed to obtain a catalyst. In this catalyst, SiO 2 -Al 2 O 3 itself is an acidic catalyst and has heat resistance, so it functions both as an auxiliary catalyst and as a support. Therefore, as the gas sensitive body 3, for example, a ZnO-based oxide semiconductor is used as the first
As shown in the figure, it is coated on an insulating substrate 1 provided with a pair of electrodes 2, dried and fired to form a gas sensitive layer. Thereafter, the above-mentioned catalyst is made into a slurry using a suitable solvent, coated on the surface of the gas-sensitive member 3, dried, and further calcined at 300 to 1000°C to form a catalyst layer to obtain a gas-sensitive element. Various characteristics were measured for the examples according to the present invention manufactured by the method described above, and the first
Shown in the table. In Table 1, Ro indicates the resistance value in air, and Rg indicates the resistance value in 0.2% gas concentration. In addition, the sensitivity in the cutout is expressed as Ro/Rg, and the change over time indicates the rate of change in resistance value after 1000 hours of energization.
【表】【table】
【表】
第１表から明らかな如く、ZnO系酸化物半導体
から成るガス感応体表面にPtの塩化物を含む触
媒層を用いた場合はいずれもC4H10（イソブタン
ガス）に対して感度を示すが、比較例のようにガ
ス感応体と触媒との混合体もしくは含浸体では充
分な感度、選択性、経時変化特性を得る事ができ
なかつた。これに愛し本願発明に係る実施例で
は、感度、選択性、経時変化特性の全てに亘り優
れた特性を示している。
また本発明に係る感ガス素子において、触媒を
適宜選択する事により、各種ガスに対し優れた特
性を示す感ガス素子を得る事ができる。例えば上
記実施例と同様にしてPdの塩化物を含む触媒層
を用いた場合は第２表に示す如くC4H10には感応
せず、H2、Coに感応し優れた特性を示す。[Table] As is clear from Table 1, when a catalyst layer containing Pt chloride is used on the surface of a gas sensitive body made of a ZnO-based oxide semiconductor, the sensitivity to C 4 H 10 (isobutane gas) increases. However, as in the comparative example, it was not possible to obtain sufficient sensitivity, selectivity, and characteristics over time with a mixture or impregnated body of a gas sensitive material and a catalyst. In contrast, the embodiments according to the present invention exhibit excellent characteristics in all aspects of sensitivity, selectivity, and temporal change characteristics. Further, in the gas-sensitive element according to the present invention, by appropriately selecting a catalyst, it is possible to obtain a gas-sensitive element that exhibits excellent characteristics against various gases. For example, when a catalyst layer containing Pd chloride is used in the same manner as in the above example, it is not sensitive to C 4 H 10 but sensitive to H 2 and Co, exhibiting excellent properties as shown in Table 2.
【表】
なお上記においてPt、Pdの塩化物を含む触媒
層を一層のみ用いた場合を示したが、さらにその
表面に異種の触媒層を設けることもできる。
以上の如く本発明に係る感ガス素子は、感度、
選択性、経時変化特性に優れており、また製造上
においても、触媒層およびガス感応体を適宜選択
することにより、各種使用目的により選択性、感
度を調整することができる。さらに製造時におけ
る焼成温度調整が容易になるなど、実用上極めて
有効なものと言える。[Table] Although the case where only one catalyst layer containing Pt or Pd chlorides is used is shown above, it is also possible to further provide different types of catalyst layers on the surface. As described above, the gas-sensitive element according to the present invention has sensitivity,
It has excellent selectivity and aging characteristics, and during production, selectivity and sensitivity can be adjusted depending on various purposes of use by appropriately selecting the catalyst layer and gas receptor. Furthermore, it can be said that it is extremely effective in practice, as it makes it easier to adjust the firing temperature during manufacturing.
第１図は本発明の構成例を示す断面図、第２図
は本発明を用いる際の装置を示す斜視図である。
１……絶縁基体、２……電極、３……ガス感応
体層、４……触媒層。
FIG. 1 is a sectional view showing a configuration example of the present invention, and FIG. 2 is a perspective view showing an apparatus when using the present invention. 1... Insulating base, 2... Electrode, 3... Gas sensitive layer, 4... Catalyst layer.
Claims (1)
れた酸化物半導体からなるガス感応体層上に、
Pt又はPdの塩化物を含む触媒と、Al2O3、SiO2
及びZrO2から選ばれた少なくとも一種から成る
担体を少なくとも含みスラリー化された触媒原料
を塗布焼成して触媒層を形成することを特徴とす
る感ガス素子の製造方法。 ２ 特許請求の範囲第１項において、酸化物半導
体としてZnO系ガス感応体を用いたことを特徴と
する感ガス素子の製造方法。[Claims] 1. On a gas sensitive layer made of an oxide semiconductor formed with a pair of electrodes on the surface of an insulating substrate,
Catalyst containing Pt or Pd chloride, Al 2 O 3 , SiO 2
1. A method for producing a gas-sensitive element, comprising applying and firing a catalyst raw material slurry containing at least one carrier selected from ZrO 2 and ZrO 2 to form a catalyst layer. 2. A method for producing a gas-sensitive element according to claim 1, characterized in that a ZnO-based gas-sensitive element is used as the oxide semiconductor.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP18017383A JPS5981549A (en) | 1983-09-30 | 1983-09-30 | Preparation of gas sensitive element |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP18017383A JPS5981549A (en) | 1983-09-30 | 1983-09-30 | Preparation of gas sensitive element |
Related Parent Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP869877A Division JPS5395097A (en) | 1977-01-31 | 1977-01-31 | Gas-sensitive element |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5981549A JPS5981549A (en) | 1984-05-11 |
| JPH0322584B2 true JPH0322584B2 (en) | 1991-03-27 |
Family
ID=16078669
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP18017383A Granted JPS5981549A (en) | 1983-09-30 | 1983-09-30 | Preparation of gas sensitive element |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5981549A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1994015203A1 (en) * | 1992-12-23 | 1994-07-07 | Robert Bosch Gmbh | Sensor for the determination of gas components and/or gas concentrations of gas mixtures |
-
1983
- 1983-09-30 JP JP18017383A patent/JPS5981549A/en active Granted
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1994015203A1 (en) * | 1992-12-23 | 1994-07-07 | Robert Bosch Gmbh | Sensor for the determination of gas components and/or gas concentrations of gas mixtures |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5981549A (en) | 1984-05-11 |
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