JP2958452B2 - Method for producing composite porous sensor - Google Patents
Method for producing composite porous sensorInfo
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- JP2958452B2 JP2958452B2 JP10064271A JP6427198A JP2958452B2 JP 2958452 B2 JP2958452 B2 JP 2958452B2 JP 10064271 A JP10064271 A JP 10064271A JP 6427198 A JP6427198 A JP 6427198A JP 2958452 B2 JP2958452 B2 JP 2958452B2
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- Prior art keywords
- particles
- gas sensor
- sensor element
- gas
- semiconductor
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Description
【発明の詳細な説明】DETAILED DESCRIPTION OF THE INVENTION
【０００１】[0001]
【発明の属する技術分野】本発明は新規な半導体ガスセ
ンサー素子、さらに詳しく言えば、半導体ガスセンサー
材料粒子の表面上に局所的に制御して、ガスセンサー材
料の機能を増幅する触媒機能を有する金属粒子を分散さ
せた複合粒子を、気孔率の高い多孔性の状態で堆積させ
た半導体ガスセンサー素子に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel semiconductor gas sensor element, and more particularly, to a catalytic function for amplifying the function of a gas sensor material by locally controlling the surface of semiconductor gas sensor material particles. The present invention relates to a semiconductor gas sensor element in which composite particles in which metal particles are dispersed are deposited in a porous state having a high porosity.
【０００２】[0002]
【従来の技術】ガスセンサーは水素やエタノールなどの
可燃性ガスの漏洩検知に広く使用されるとともに、近年
では食品や環境関連分野での芳香成分や毒性ガスの検知
などにも利用されるようになっている。そのため対象ガ
スのより微量成分の検知や、ガス選択性の向上、検知ガ
ス種の拡大などが求められていた。2. Description of the Related Art Gas sensors have been widely used for detecting leaks of flammable gases such as hydrogen and ethanol, and in recent years have been used for detecting aroma components and toxic gases in food and environment-related fields. Has become. Therefore, there has been a demand for detection of a trace component of the target gas, improvement of gas selectivity, expansion of detection gas types, and the like.
【０００３】ガスセンサーはガスとの接触により電気抵
抗が急変するが、より微量のガスでも抵抗変化を生じさ
せるために、ガスセンサー材料とガスとの反応性を増幅
させるための触媒粒子（金属や酸化物など）を添加する
方法が有効である。現在までの触媒粒子の添加方法は金
属塩を用いた液相法（含浸法）が一般的で、その微細な
粒子径のために凝集しやすい触媒粒子を必ずしもガスセ
ンサー材料粒子の表面のみに分散できているわけではな
かった。簡便な方法で制御性よく触媒粒子をガスセンサ
ー材料粒子の表面に分散させるために、触媒粒子の添加
方法には改良の余地が指摘されていた（山添昇、玉置
純：“半導体ガスセンサにおける金属微粒子の役割”、
表面、ｖｏｌ．２７、Ｎｏ．６、４９９−５０７（１９
８９））。[0003] In a gas sensor, the electrical resistance changes suddenly due to contact with a gas. However, in order to cause a change in the resistance even with a smaller amount of gas, catalyst particles (metal or metal) for amplifying the reactivity between the gas sensor material and the gas are used. Is effective. Up to now, the method of adding catalyst particles is generally a liquid phase method (impregnation method) using a metal salt, and due to the fine particle diameter, easily agglomerated catalyst particles are necessarily dispersed only on the surface of the gas sensor material particles. It was not done. It was pointed out that there was room for improvement in the method of adding the catalyst particles in order to disperse the catalyst particles on the surface of the gas sensor material particles in a simple manner with good controllability (Noboru Yamazoe, Jun Tamaki: "Metal fine particles in semiconductor gas sensors" Role of, "
Surface, vol. 27, no. 6, 499-507 (19
89)).
【０００４】またガスセンサーは内部電極型厚膜素子と
して用いられることが多く、素子全体が緻密になると対
象ガスの厚膜内部への拡散透過性が悪くなり、素子の応
答性が低下する。そのためガスセンサー素子の気孔率を
制御し、多孔性の素子構造とする必要性が指摘されてい
た（安藤正美、土田敬之、三浦則雄、山添昇：“二酸化
スズ膜を用いたセンサー素子の硫化水素検知特性に対す
る微細構造の影響”、日本化学会誌、Ｎｏ．４、３４８
−３５３（１９９６））。A gas sensor is often used as an internal electrode type thick film element. If the whole element becomes dense, the diffusion permeability of a target gas into the inside of the thick film deteriorates, and the response of the element decreases. Therefore, it was pointed out that it was necessary to control the porosity of the gas sensor element to make it a porous element structure. Influence of Microstructure on Detection Characteristics ", Journal of the Chemical Society of Japan, No. 4, 348
-353 (1996)).
【０００５】[0005]
【発明が解決しようとする課題】本発明は、このような
従来のガスセンサー素子が持つ欠点を克服し、ガスセン
サー材料とガスとの反応性を増幅させるための触媒粒子
を、センサー材料粒子の表面上に局所的に制御して分散
させるとともに、同時に気孔率の高い多孔性のセンサー
素子を与えることができる半導体−金属複合粒子ガスセ
ンサー素子の製造方法を提供するものであり、例えば、
ＳｎＯ2 、ＺｎＯ、ＴｉＯ2 などのガスセンサー材料と
Ｐｄ、Ｐｔ、Ａｕ、Ｒｕなどの触媒粒子が複合された半
導体ガスセンサー素子として好適な、ガスセンサー粒子
の表面上に局所的に制御して、触媒粒子を分散させた複
合粒子から成る、多孔性のガスセンサー素子を提供する
ことを目的として開発されたものである。SUMMARY OF THE INVENTION The present invention overcomes the above-mentioned drawbacks of the conventional gas sensor element and replaces the catalyst particles for amplifying the reactivity between the gas sensor material and the gas with the sensor material particles. It is intended to provide a method for producing a semiconductor-metal composite particle gas sensor element capable of locally controlling and dispersing on a surface and simultaneously providing a porous sensor element having a high porosity.
A gas sensor material such as SnO 2 , ZnO, and TiO 2 and a catalyst particle such as Pd, Pt, Au, and Ru are suitably combined as a semiconductor gas sensor element, which is locally controlled on the surface of the gas sensor particles. The present invention has been developed for the purpose of providing a porous gas sensor element composed of composite particles in which catalyst particles are dispersed.
【０００６】[0006]
【課題を解決するための手段】本発明者らは、ガスセン
サー粒子の表面上に局所的に制御して触媒粒子を分散さ
せた複合粒子から成る、多孔性のガスセンサー素子を開
発すべく鋭意研究を重ねた結果、ガスセンサー材料粒子
と触媒粒子に対し、一方に正の静電気を、他方に負の静
電気をそれぞれ荷電したのち、両者を混合することによ
り、ガスセンサー材料粒子の表面上に局所的に制御して
触媒粒子を分散できることを見出した。さらに得られた
ガスセンサー材料粒子と触媒粒子の複合粒子に対し、正
または負の静電気を荷電したのち、あらかじめ内部電極
を取り付けたセンサー基板を複合粒子と反対極性に荷電
または接地し、複合粒子を基板上に堆積することで、数
珠玉形成力（Ｐｅａｒｌ Ｃｈａｉｎ Ｆｏｒｍｉｎｇ
Ｆｏｒｃｅ）により気孔率の高い多孔性の状態で複合
粒子を堆積可能なことを見出した。本発明はかかる知見
に基づいて完成したものである。Means for Solving the Problems The present inventors have been keen to develop a porous gas sensor element comprising composite particles in which catalyst particles are locally controlled on the surface of gas sensor particles. As a result of repeated research, the gas sensor material particles and the catalyst particles were charged with positive static electricity on one side and negative static electricity on the other, and then mixed together to form a localized charge on the surface of the gas sensor material particles. It has been found that the catalyst particles can be dispersed under controlled conditions. Further, after charging the obtained composite particles of the gas sensor material particles and the catalyst particles with positive or negative static electricity, the sensor substrate on which the internal electrodes are previously attached is charged or grounded to the opposite polarity to the composite particles, and the composite particles are discharged. By depositing on a substrate, a Pearl Chain Forming
Force) to deposit composite particles in a porous state with high porosity. The present invention has been completed based on such findings.
【０００７】すなわち本発明は、第１にガスセンサー材
料粒子と触媒粒子に対し、一方に正の静電気を、他方に
負の静電気をそれぞれ荷電したのち、両者を静電気的に
結合すること、第２に得られたガスセンサー材料粒子と
触媒粒子の複合粒子を静電気的にセンサー基板上に堆積
することを特徴とするガスセンサー素子を提供するもの
である。That is, the present invention firstly charges a gas sensor material particle and a catalyst particle with a positive static electricity on one side and a negative static electricity on the other, and then electrostatically couples both. And a composite particle of the gas sensor material particles and the catalyst particles obtained above is electrostatically deposited on a sensor substrate.
【０００８】上記課題を解決するために、本発明では以
下のような構成が採用される。 （１）１μｍ以下の半導体ガスセンサー粒子の表面上に
制御して、センサー機能を増幅する能力を有する１００
ｎｍ以下の金属粒子を分散させた半導体−金属複合粒子
を、気孔率の高い多孔性の状態で堆積させることを特徴
とする、半導体ガスセンサー素子の製造方法。 （２）上記半導体−金属複合粒子を静電凝集法で合成
し、当該半導体−金属複合粒子を静電沈着により粒子が
数珠玉状に連なった状態で堆積した多孔性の厚膜構造と
することを特徴とする前記（１）記載の半導体ガスセン
サー素子の製造方法。 （３）上記半導体がＳｎＯ2 、ＺｎＯ又はＴｉＯ2 であ
り、金属粒子がＰｄ、Ｐｔ、Ａｕ又はＲｕである前記
（１）又は（２）記載の半導体ガスセンサー素子の製造
方法。In order to solve the above problems, the present invention employs the following configuration. (1) 100 having the ability to control on the surface of semiconductor gas sensor particles of 1 μm or less to amplify the sensor function
A method for producing a semiconductor gas sensor element, comprising depositing semiconductor-metal composite particles in which metal particles having a diameter of not more than nm are dispersed in a porous state having a high porosity. (2) The above-mentioned semiconductor-metal composite particles are synthesized by an electrostatic aggregation method, and the semiconductor-metal composite particles are formed into a porous thick film structure in which the particles are deposited in a state of beads by electrostatic deposition. The method for manufacturing a semiconductor gas sensor element according to the above (1), which is characterized in that: (3) The method for producing a semiconductor gas sensor element according to (1) or (2), wherein the semiconductor is SnO 2 , ZnO or TiO 2 , and the metal particles are Pd, Pt, Au or Ru.
【０００９】[0009]
【発明の実施の形態】次に、本発明についてさらに詳細
に説明する。本発明方法においては、まずガスセンサー
材料粒子と触媒粒子をＣＶＤ法などの方法により合成す
る。このさいのガスセンサー材料粒子については例えば
ＳｎＯ2 、ＺｎＯ、ＴｉＯ2 などの半導体粒子が、触媒
粒子についてはＰｄ、Ｐｔ、Ａｕ、Ｒｕなどの金属粒子
が例示されるが、特に制限はない。Next, the present invention will be described in more detail. In the method of the present invention, first, gas sensor material particles and catalyst particles are synthesized by a method such as a CVD method. At this time, the gas sensor material particles include, for example, semiconductor particles such as SnO 2 , ZnO, and TiO 2 , and the catalyst particles include metal particles such as Pd, Pt, Au, and Ru, but are not particularly limited.
【００１０】次に得られたガスセンサー材料粒子と触媒
粒子に任意の大きさおよび極性の静電気をそれぞれ荷電
し、両者を混合することで、反対極性に荷電された粒子
同士に働く静電凝集力により、ガスセンサー材料粒子の
表面に触媒粒子が付着した複合粒子が合成される。この
さいの粒子の荷電方法については、例えば双方向衝突荷
電法などが例示されるが、特に制限はない。Next, the obtained gas sensor material particles and catalyst particles are charged with static electricity of an arbitrary size and polarity, respectively, and the two are mixed to form an electrostatic cohesive force acting on the oppositely charged particles. Thereby, composite particles having catalyst particles adhered to the surfaces of the gas sensor material particles are synthesized. The method of charging the particles at this time is exemplified by, for example, a two-way collision charging method, but is not particularly limited.
【００１１】つづいて得られたガスセンサー材料粒子と
触媒粒子の複合粒子に対し、正または負の静電気を荷電
したのち、あらかじめ内部電極を取り付けたセンサー基
板を複合粒子と反対極性に荷電または接地し、複合粒子
を基板上に静電気的に堆積することで、荷電された粒子
が基板上に堆積するときに働く数珠玉形成力により、気
孔率の高い多孔性の状態で複合粒子が堆積されたガスセ
ンサー素子が得られる。このさいの複合粒子の荷電方法
については例えば双方向衝突荷電法などが、基板の荷電
方法については直流高圧電源を利用する方法などが例示
されるが、特に制限されるものではない。Subsequently, positive or negative static electricity is charged to the obtained composite particles of the gas sensor material particles and the catalyst particles, and then the sensor substrate provided with the internal electrodes is charged or grounded to the opposite polarity to the composite particles. A gas sensor in which the composite particles are deposited in a porous state with a high porosity by the electrostatic deposition of the composite particles on the substrate, and the beads forming force acting when the charged particles deposit on the substrate An element is obtained. In this case, as a method of charging the composite particles, for example, a two-way collision charging method or the like is exemplified, and as a method of charging the substrate, a method using a DC high-voltage power supply is exemplified, but the method is not particularly limited.
【００１２】次に、本発明を添付図面にしたがって説明
する。図１は本発明によってＳｎＯ2 ガスセンサー材料
粒子とＰｄ触媒粒子の複合粒子から成るガスセンサー素
子を製造する場合の装置の１例、図２は図１の装置で得
られたガスセンサー素子の１例の説明図である。Next, the present invention will be described with reference to the accompanying drawings. FIG. 1 shows an example of an apparatus for producing a gas sensor element comprising composite particles of SnO 2 gas sensor material particles and Pd catalyst particles according to the present invention, and FIG. 2 shows one of the gas sensor elements obtained by the apparatus of FIG. It is explanatory drawing of an example.
【００１３】図１の方法では、蒸気発生装置１でテトラ
メチルスズＳｎ（ＣＨ3 ）4 を気化温度０℃に設定して
Ｓｎ（ＣＨ3 ）4 蒸気を発生させ、０．０１〜０．５ｌ
／ｍｉｎのＡｒをキャリアガス２としてＳｎ（ＣＨ3 ）
4 蒸気を５００〜８００℃に温度を保った反応器５へ送
り、同時に反応ガス３として０．１〜０．５ｌ／ｍｉｎ
のＯ2 とシースガス４としてＮ2 を０〜５ｌ／ｍｉｎで
供給して、反応器５中の化学反応でＳｎＯ2 ガスセンサ
ー材料粒子を合成する。In the method of FIG. 1, the vapor generator 1 sets the vaporization temperature of tetramethyltin Sn (CH 3 ) 4 to 0 ° C. to generate Sn (CH 3 ) 4 vapor, which is 0.01 to 0.5 l.
/ Min Ar as carrier gas 2 and Sn (CH 3 )
4 steam feed to the reactor 5 kept at a temperature of 500~800 ℃, 0.1~0.5l / min as the reaction gas 3 at the same time
O 2 and N 2 as the sheath gas 4 are supplied at 0 to 5 l / min to synthesize SnO 2 gas sensor material particles by a chemical reaction in the reactor 5.
【００１４】Ｐｄ触媒粒子はアルミナ管状炉などの反応
器５’中にＰｄ原料粉体６を置き、粒径最適化のため反
応器５’を１５００〜１７００℃に加熱して蒸気を発生
させ、Ｎ2 １〜５ｌ／ｍｉｎをキャリアガス２’、Ｎ2
（例えば、５ｌ／ｍｉｎ）をシ−スガス４’として供給
して、反応器５’中の蒸発−凝縮反応で合成する。For the Pd catalyst particles, the Pd raw material powder 6 is placed in a reactor 5 ′ such as an alumina tubular furnace, and the reactor 5 ′ is heated to 1500 to 1700 ° C. to optimize the particle size to generate steam, N 2 1~5l / min carrier gas 2 ', N 2
(E.g., 5 l / min) is supplied as a sheath gas 4 'and is synthesized by an evaporation-condensation reaction in the reactor 5'.
【００１５】次に熱拡散による壁面沈着防止のため、炉
内であらかじめ加熱したＮ2 をシース（Ｓｈｅａｔｈ）
状に供給し、得られたＳｎＯ2 ガスセンサー材料粒子を
荷電器（ボクサーチャージャー）７へ、Ｐｄ触媒粒子を
荷電器７’へそれぞれ輸送し、任意の大きさおよび極性
（例えばＳｎＯ2 に正、Ｐｄに負など）の静電気を荷電
する。つづいて両者を混合することで、反対極性に荷電
された粒子同士に働く静電凝集力により、ＳｎＯ2 ガス
センサー材料粒子の表面にＰｄ触媒粒子が付着した複合
粒子が合成される。Next, in order to prevent wall deposition due to thermal diffusion, N 2 preheated in a furnace is covered with a sheath (Shearth).
The resulting SnO 2 gas sensor material particles are transported to a charger (boxer charger) 7 and the Pd catalyst particles are transported to a charger 7 ′, and have any size and polarity (for example, positive or negative for SnO 2) . (Pd is negative). Subsequently, by mixing them, composite particles having Pd catalyst particles adhered to the surfaces of SnO 2 gas sensor material particles are synthesized by electrostatic cohesion acting on particles charged in opposite polarities.
【００１６】次にＳｎＯ2 −Ｐｄ複合粒子に対し、例え
ば負の静電気を荷電したのち、あらかじめ内部電極を取
り付けたセンサー基板を例えば接地して、複合粒子を基
板上に静電気的に堆積することで、荷電された粒子が基
板上に堆積するときに働く数珠玉形成力により、気孔率
の高い多孔性の状態で複合粒子が堆積された図２に示す
ようなＳｎＯ2 −Ｐｄガスセンサー素子が得られる。粒
子を輸送してきたガスなどはポンプ９で排気する。上記
方法により、例えば、５０〜１００ｎｍのＳｎＯ2 核粒
子表面をナノメーターオーダーのＰｄ粒子が均一に被覆
した複合粒子が得られることがわかった。また、ファラ
デーケージ電流計で粒子の帯電量を測定した結果、粒子
は荷電器によって単極性荷電の飽和帯電量まで荷電され
ていることが明らかとなった。一方、荷電を行わずにＳ
ｎＯ2 粒子とＰｄ粒子を混合した場合には、両者が別々
に補集されて複合粒子化していない部分が存在すること
があった。また、上記半導体−金属複合粒子を静電沈着
により粒子が数珠玉状に連なった状態で堆積した多孔性
の厚膜構造とすることができることがわかった。この多
孔構造はアニール後も維持された。上記厚膜構造の半導
体−金属複合粒子は、不燃性ガスに対する優れたセンサ
ー機能を有することがわかった。Next, after charging the SnO 2 -Pd composite particles with, for example, negative static electricity, the sensor substrate on which the internal electrodes are previously attached is grounded, for example, and the composite particles are electrostatically deposited on the substrate. The SnO 2 -Pd gas sensor element as shown in FIG. 2 in which the composite particles are deposited in a porous state having a high porosity is obtained by the beads forming force acting when the charged particles are deposited on the substrate. . The gas transporting the particles is exhausted by the pump 9. According to the above method, for example, it was found that composite particles in which the surface of SnO 2 core particles of 50 to 100 nm was uniformly coated with Pd particles of the order of nanometers were obtained. In addition, as a result of measuring the charge amount of the particles with a Faraday cage ammeter, it was found that the particles were charged by the charger to a saturated charge amount of unipolar charge. On the other hand, S
When the nO 2 particles and the Pd particles were mixed, there were cases where both were separately collected and there were portions that were not formed into composite particles. In addition, it was found that the semiconductor-metal composite particles can be formed into a porous thick film structure in which the particles are deposited in a state of a bead by electrostatic deposition. This porous structure was maintained after annealing. It was found that the semiconductor-metal composite particles having the thick film structure had an excellent sensor function for nonflammable gas.
【００１７】[0017]
【実施例】次に実施例により本発明をさらに詳細に説明
するが、本発明はこの例によってなんら限定されるもの
ではない。Next, the present invention will be described in more detail by way of examples, which should not be construed as limiting the present invention.
【００１８】実施例１ 本実施例では、図１に示した装置及び方法によりＳｎＯ
2 ガスセンサー素子を作製した。 （１）方法 蒸気発生装置１でテトラメチルスズＳｎ（ＣＨ3 ）4 を
気化温度０℃に設定してＳｎ（ＣＨ3 ）4 蒸気を発生さ
せ、０．０１〜０．５ｌ／ｍｉｎのＡｒをキャリアガス
２としてＳｎ（ＣＨ3 ）4 蒸気を５００〜８００℃に温
度を保った反応器５へ送り、同時に反応ガス３として
０．１〜０．５ｌ／ｍｉｎのＯ2 とシースガス４として
Ｎ2 を０〜５ｌ／ｍｉｎで供給して、反応器５中の化学
反応でＳｎＯ2 ガスセンサー材料粒子を合成した。Embodiment 1 In this embodiment, SnO 2 is formed by the apparatus and method shown in FIG.
Two gas sensor elements were fabricated. (1) Method Tetramethyltin Sn (CH 3 ) 4 is set to a vaporization temperature of 0 ° C. by the steam generator 1 to generate Sn (CH 3 ) 4 vapor, and 0.01 to 0.5 l / min of Ar is generated. As a carrier gas 2, Sn (CH 3 ) 4 vapor is sent to a reactor 5 maintained at a temperature of 500 to 800 ° C., and at the same time, O 2 of 0.1 to 0.5 l / min as a reaction gas 3 and N 2 as a sheath gas 4 Was supplied at 0 to 5 l / min to synthesize SnO 2 gas sensor material particles by a chemical reaction in the reactor 5.
【００１９】Ｐｄ触媒粒子は還元ガス中の蒸発−凝縮法
で合成した。反応器５’中にＰｄ原料粉体６を置き、反
応器５’を１６００℃に加熱して蒸気を発生させ、Ｎ2
１ｌ／ｍｉｎをキャリアガス２’、Ｎ2 ５ｌ／ｍｉｎを
シ−スガス４’として供給して、反応器５’中の蒸発−
凝縮反応でＰｄ触媒粒子を合成した。The Pd catalyst particles were synthesized by an evaporation-condensation method in a reducing gas. The Pd raw material powder 6 is placed in the reactor 5 ′, and the reactor 5 ′ is heated to 1600 ° C. to generate steam, and N 2
1l / min carrier gas 2 ', the N 2 5l / min sheet - Sugasu 4' is supplied as the reactor 5 'evaporation during -
Pd catalyst particles were synthesized by a condensation reaction.
【００２０】次に、得られたＳｎＯ2 ガスセンサー材料
粒子を荷電器７へ、Ｐｄ触媒粒子を荷電器７’へそれぞ
れ輸送し、ＳｎＯ2 に正、Ｐｄに負の静電気を荷電し
た。つづいて荷電粒子を混合し、反対極性に荷電された
粒子同士に働く静電凝集力を利用して、ＳｎＯ2 ガスセ
ンサー材料粒子の表面にＰｄ触媒粒子が付着したＳｎＯ
2 −Ｐｄ複合粒子を合成した。Next, the obtained SnO 2 gas sensor material particles were transported to the charger 7, and the Pd catalyst particles were transported to the charger 7 ′, and the positive static electricity was charged to SnO 2 and the negative static electricity was charged to Pd. Subsequently, the charged particles are mixed, and the Pd catalyst particles adhere to the surfaces of the SnO 2 gas sensor material particles by utilizing the electrostatic cohesion acting on the particles charged in opposite polarities.
2- Pd composite particles were synthesized.
【００２１】次に、ＳｎＯ2 −Ｐｄ複合粒子に対し、負
の静電気を荷電したのち、当該複合粒子を、あらかじめ
Ｐｄ電極を取り付けた石英製センサー基板上に静電沈着
させ、荷電された粒子が基板上に数珠玉状に連なった状
態で堆積した、気孔率の高い多孔性の厚膜構造の図２に
示すＳｎＯ2 −Ｐｄガスセンサー素子を得た。Next, after charging the SnO 2 -Pd composite particles with negative static electricity, the composite particles are electrostatically deposited on a quartz sensor substrate to which a Pd electrode is previously attached, and the charged particles are charged. The SnO 2 -Pd gas sensor element shown in FIG. 2 having a high porosity and a porous thick film structure, which was deposited on the substrate in a beaded state, was obtained.
【００２２】（２）結果 図３に本発明の方法で得られたＳｎＯ2 −Ｐｄ複合粒子
の電子顕微鏡写真を示す。この複合粒子は、１００ｎｍ
以下のＳｎＯ2 ガスセンサー材料粒子の表面に、１０ｎ
ｍ以下のＰｄ触媒粒子が均一に付着した構造であった。(2) Results FIG. 3 shows an electron micrograph of the SnO 2 -Pd composite particles obtained by the method of the present invention. This composite particle has a thickness of 100 nm.
On the surface of the following SnO 2 gas sensor material particles, 10 n
m or less Pd catalyst particles were uniformly attached.
【００２３】実施例２ 実施例１のＳｎＯ2 −Ｐｄ複合粒子を用いて、本発明の
方法で作製したガスセンサー素子表面の電子顕微鏡写真
を図４に示す。数珠玉形成作用により粒子が数珠玉上に
連なった状態で堆積した多孔性の厚膜構造となった。ま
た図５にはＳｎＯ2 −Ｐｄガスセンサー素子表面のＳｎ
成分とＰｄ成分の組成分布を示す。Ｓｎ成分とＰｄ成分
が同じ位置に分布しており、触媒粒子はガスセンサー材
料粒子の表面上に局所的に制御されて分散していた。Example 2 FIG. 4 shows an electron micrograph of the surface of a gas sensor element produced by the method of the present invention using the SnO 2 -Pd composite particles of Example 1. The beads formed a porous thick film structure in a state where the particles continued to form on the beads by the beads forming action. FIG. 5 shows the SnO 2 -Pd gas sensor element surface Sn
3 shows the composition distribution of the component and the Pd component. The Sn component and the Pd component were distributed at the same position, and the catalyst particles were locally controlled and dispersed on the surfaces of the gas sensor material particles.
【００２４】実施例３ 実施例２のＳｎＯ2 −Ｐｄガスセンサー素子を用いて、
いくつかの可燃性ガス（エタノールＣ2 Ｈ5 ＯＨ、水素
Ｈ2 、メタンＣＨ4 ）の検知に利用した結果を図６に示
す。各可燃性ガスのガス感度（Ｓｅｎｓｉｔｉｖｉｔ
ｙ）がガス濃度（Ｇａｓ Ｃｏｎｃｅｎｔｒａｔｉｏ
ｎ）に比例しており、また特に低ガス濃度側は５０ｐｐ
ｍ以下のガス検知も可能で、ＳｎＯ2 −Ｐｄガスセンサ
ー素子は可燃性ガスに対する高いセンサー機能を示し
た。Example 3 Using the SnO 2 -Pd gas sensor element of Example 2,
FIG. 6 shows the results of use for detecting some combustible gases (ethanol C 2 H 5 OH, hydrogen H 2 , methane CH 4 ). Sensitivity of each flammable gas
y) is the gas concentration (Gas Concentratio)
n), and especially 50 pp on the low gas concentration side.
m or less, and the SnO 2 -Pd gas sensor element exhibited a high sensor function for combustible gas.
【００２５】[0025]
【発明の効果】本発明の方法により、５０〜１００ｎｍ
のＳｎＯ2 等の核粒子表面をナノメーターオーダーのＰ
ｄ等の粒子が均一に被覆した複合粒子が得られる。本発
明によると、素子中でガスセンサー材料粒子の表面上に
局所的に制御して触媒粒子を分散することができ、さら
に粒子が数珠玉状に連なった状態で堆積した多孔性の厚
膜構造が得られる。すなわち本発明によると触媒粒子の
分散状態と厚膜構造を同時に制御した素子を容易に作製
することができ、この積層膜は、ガスセンサー素子とし
て好適である。According to the method of the present invention, 50 to 100 nm
Surface of nuclear particles such as SnO 2
Composite particles uniformly covered with particles such as d can be obtained. According to the present invention, the catalyst particles can be locally controlled on the surface of the gas sensor material particles in the element to disperse the catalyst particles, and further, a porous thick film structure in which the particles are deposited in a bead-like state is obtained. can get. That is, according to the present invention, an element in which the dispersion state of the catalyst particles and the thick film structure are simultaneously controlled can be easily produced, and this laminated film is suitable as a gas sensor element.
【図１】本発明を実施するための装置の１例の説明図で
ある。FIG. 1 is an explanatory diagram of an example of an apparatus for implementing the present invention.
【図２】本発明で得られたガスセンサー素子の１例の説
明図である。FIG. 2 is an explanatory diagram of one example of a gas sensor element obtained by the present invention.
【図３】本発明により得られたＳｎＯ2 ガスセンサー材
料粒子とＰｄ触媒粒子の複合粒子の１例の電子顕微鏡写
真である。FIG. 3 is an electron micrograph of an example of composite particles of SnO 2 gas sensor material particles and Pd catalyst particles obtained according to the present invention.
【図４】本発明で作製したＳｎＯ2 −Ｐｄ複合粒子から
成るガスセンサー素子の表面の電子顕微鏡写真である。FIG. 4 is an electron micrograph of the surface of a gas sensor element composed of SnO 2 -Pd composite particles produced according to the present invention.
【図５】本発明で作製したＳｎＯ2 −Ｐｄガスセンサー
素子の表面のＳｎ成分とＰｄ成分の組成分布図（ＦＰＭ
ＡによるＳｎＯ2 −Ｐｄ複合体組織の写真）である。FIG. 5 is a composition distribution diagram (FPM) of a Sn component and a Pd component on the surface of a SnO 2 -Pd gas sensor element manufactured according to the present invention.
A is a photograph of the SnO 2 -Pd composite structure).
【図６】本発明で作製したＳｎＯ2 −Ｐｄガスセンサー
素子の可燃性ガス（エタノールＣ2 Ｈ5 ＯＨ、水素
Ｈ2 、メタンＣＨ4 ）に対するガス感度図である。FIG. 6 is a gas sensitivity diagram for a combustible gas (ethanol C 2 H 5 OH, hydrogen H 2 , methane CH 4 ) of the SnO 2 -Pd gas sensor element manufactured in the present invention.
Claims (3)
スセンサー素子であって、半導体と触媒の複合粒子を、
静電気的に基板上に堆積して、気孔率の高い多孔性の厚
膜構造としたことを特徴とする、半導体ガスセンサー素
子。 1. A semiconductor gas having a gas detection catalyst dispersed and controlled.
Sensor element, a composite particle of semiconductor and catalyst ,
Electrostatically deposited on the substrate , high porosity porous thickness
Semiconductor gas sensor element characterized by having a film structure
Child.
を製造する方法であって、半導体と触媒の複合粒子を静
電凝集法で合成し、当該複合粒子を静電沈着により粒子
が数珠玉状に連なった状態で堆積した多孔性の厚膜構造
とすることを特徴とする半導体ガスセンサー素子の製造
方法。2. The semiconductor gas sensor element according to claim 1,
A method of manufacturing a semiconductor composite particles of the catalyst synthesized in electrostatic coalescence method, those plurality if particles particles by electrostatic deposition and is deposited in a state of continuous in Job's tears shaped porous thick film structures method of manufacturing a semi-conductor gas sensor element you characterized in that a.
る請求項２記載の半導体ガスセンサー素子の製造方法。3. The method for producing a semiconductor gas sensor element of the semi-conductor SnO 2, claim 2, wherein metallic particles Ru Oh <br/> at P d.
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|---|---|---|---|
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP10064271A JP2958452B2 (en) | 1998-02-26 | 1998-02-26 | Method for producing composite porous sensor |
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