JP2009128184A - Co2 sensor - Google Patents

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JP2009128184A
JP2009128184A JP2007303396A JP2007303396A JP2009128184A JP 2009128184 A JP2009128184 A JP 2009128184A JP 2007303396 A JP2007303396 A JP 2007303396A JP 2007303396 A JP2007303396 A JP 2007303396A JP 2009128184 A JP2009128184 A JP 2009128184A
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alkali metal
zirconate
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JP4936467B2 (en
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Yoshihiro Yamamoto
吉弘 山本
Masakazu Sai
正和 佐井
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Figaro Engineering Inc
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Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem wherein the electromotive force of conventional CO<SB>2</SB>sensors, the detection electrodes of which are made of alkali metal carbonate, such as, lithium carbonate is significantly shifted, when left standing under a high-humidity condition, and to improve the sensor in moisture resistance. <P>SOLUTION: The CO<SB>2</SB>sensor is configured, such that a counter electrode and the detection electrode contact with an alkali ion conductor, and a heater for heating them is disposed thereon. The detection electrode of the sensor is made up of noble metal and alkali metal zirconate. Since the amount of migration in the alkali metal zirconate due to dew condensation is small, activity of alkali metal ions, such as lithium ions, can be kept constant, and an electrode reaction with CO<SB>2</SB>can be carried out reversibly, thereby improving the CO<SB>2</SB>sensor in moisture resistance. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

この発明はアルカリ金属イオン伝導体を用いたCO2センサに関し、特にその耐湿性の改善に関する。 The present invention relates to a CO 2 sensor using an alkali metal ion conductor, and more particularly to improvement of its moisture resistance.

ナシコン（Na1+xZr2P3-xSixO12）等のアルカリ金属伝導体と、炭酸Li等のアルカリ金属炭酸塩を用いた検知極とを用いたCO2センサは、高湿中への放置により起電力が著しくシフトするとの問題がある。このことは、結露などにより検知極の炭酸Liがマイグレーションすることや、センサの起電力に関与するLiイオンの活量が一定ではないことと関係するものと推定されている。そこでCO2センサに関して、高湿雰囲気への非加熱放置に伴う、起電力の変化を抑制する必要がある。 CO 2 sensors using alkali metal conductors such as NASICON (Na 1 + x Zr 2 P 3-x Si x O 12 ) and sensing electrodes using alkali metal carbonates such as Li carbonate are highly humid. There is a problem that the electromotive force significantly shifts due to leaving it in the room. This is presumed to be related to the migration of Li carbonate at the detection electrode due to condensation or the like, and the activity of Li ions involved in the electromotive force of the sensor being not constant. Therefore, regarding the CO 2 sensor, it is necessary to suppress the change in electromotive force that is caused by leaving it unheated in a high humidity atmosphere.

ここでCO2センサについて、関連する先行技術を示す。特許文献１：特許２８３４６７９はナシコン（Na1+xZr2P3-xSixO12）と検知極の炭酸Li等の間に、ジルコニアリッチの層を設けることを記載している。
また特許文献２：特開２００４−２３９８３１は、SnO2等の金属酸化物半導体と炭酸Li等の金属炭酸塩との混合物からなる検知極を提案している。
特許２８３４６７９ 特開２００４−２３９８３１ Here, the CO 2 sensor, illustrating a relevant prior art. Patent Document 1: Japanese Patent No. 28346679 describes that a zirconia-rich layer is provided between NASICON (Na 1 + x Zr 2 P 3-x Si x O 12 ) and Li carbonate or the like of the detection electrode.
Japanese Patent Application Laid-Open No. 2004-239831 proposes a detection electrode made of a mixture of a metal oxide semiconductor such as SnO 2 and a metal carbonate such as Li carbonate.
Patent 28346679 JP 2004-239831 A

この発明の課題は、CO2センサの耐湿性を向上することにある。 An object of the present invention is to improve the moisture resistance of a CO 2 sensor.

この発明は、アルカリイオン伝導体に接続した対極と検知極と、該アルカリイオン伝導体を加熱するヒータとを設けたCO2センサにおいて、前記検知極が貴金属とアルカリ金属のジルコン酸塩とからなることを特徴とする。
アルカリ金属のジルコン酸塩はK塩やRb塩、Cs塩などでも良いが、好ましくはNaもしくLiのジルコン酸塩とし、例えばLi2ZrO3、Li6Zr2O7、Na2ZrO3、Na6Zr2O7とする。
特に好ましくはジルコン酸塩はLi2ZrO3もしくはLi6Zr2O7で、最も好ましくはLi2ZrO3である。 The present invention provides a CO 2 sensor provided with a counter electrode connected to an alkali ion conductor, a detection electrode, and a heater for heating the alkali ion conductor, wherein the detection electrode is composed of a noble metal and an alkali metal zirconate. It is characterized by that.
The alkali metal zirconate may be K salt, Rb salt, Cs salt, etc., but preferably Na or Li zirconate, for example, Li 2 ZrO 3 , Li 6 Zr 2 O 7 , Na 2 ZrO 3, Na 6 Zr 2 O 7
Particularly preferably the zirconate is Li 2 ZrO 3 or Li 6 Zr 2 O 7 , most preferably Li 2 ZrO 3 .

CO2センサの耐湿性が低い原因として、検知極中のアルカリ金属の炭酸塩が結露によりマイグレーションすることや、CO2との直接の反応を担うLiイオンの活量が一定ではないこと、が考えられる。アルカリ金属のジルコン酸塩は一般に水溶性ではないので、結露によるマイグレーションは問題にならない。次に、アルカリ金属のジルコン酸塩はアルカリイオン伝導体であり、例えばNa2ZrO3やNa6Zr2O7はNaイオンの、Li2ZrO3やLi6Zr2O7はLiイオンの伝導体で、電極反応に必要なNaイオンやLiイオンを供給する。言い換えるとアルカリ金属のジルコン酸塩はアルカリ金属イオンのバッファとして作用し、アルカリ金属イオンの活量を一定に保つ。さらに、アルカリ金属のジルコン酸塩はCO2と可逆的に反応する。例えばLi2ZrO3の場合、400℃付近から Li2ZrO3＋CO2＝Li2CO3＋ZrO2 の反応を行い、このことはNa2ZrO3等のようにアルカリ金属の種類を変えても同様で、またLi6Zr2O7のようにアルカリ金属とZrとの比を変えても同様である。このことはLi2ZrO3等のアルカリ金属のジルコン酸塩を加熱すると、CO2との反応が容易に生じることを意味する。即ち、
2Li＋(electrode)＋2e-(electrode)+CO2(gas)+1/2O2(gas)＝Li2CO3
の電極反応がLi2ZrO3等の表面で容易に進行することを意味する。このことは他のアルカリ金属ジルコン酸塩でも同様と考えられ、また上記の電極反応は可逆である。 Possible reasons for the low humidity resistance of the CO 2 sensor are that the alkali metal carbonate in the sensing electrode migrates due to condensation and that the activity of Li ions responsible for direct reaction with CO 2 is not constant. It is done. Alkali metal zirconates are generally not water soluble, so migration due to condensation is not a problem. Next, alkali metal zirconate is an alkali ion conductor, for example, Na 2 ZrO 3 and Na 6 Zr 2 O 7 are Na ions, Li 2 ZrO 3 and Li 6 Zr 2 O 7 are Li ion conductors. The body supplies Na ions and Li ions necessary for electrode reactions. In other words, the alkali metal zirconate acts as a buffer for alkali metal ions and keeps the activity of the alkali metal ions constant. In addition, alkali metal zirconates react reversibly with CO 2 . For example, in the case of Li 2 ZrO 3 , a reaction of Li 2 ZrO 3 + CO 2 = Li 2 CO 3 + ZrO 2 is carried out from around 400 ° C. This is the same even if the type of alkali metal is changed, such as Na 2 ZrO 3 The same is true if the ratio of alkali metal to Zr is changed as in Li 6 Zr 2 O 7 . This means that when an alkali metal zirconate such as Li 2 ZrO 3 is heated, a reaction with CO 2 occurs easily. That is,
2Li + (electrode) + 2e - (electrode) + CO 2 (gas) + 1 / 2O 2 (gas) = Li 2 CO 3
This means that the electrode reaction proceeds easily on the surface of Li 2 ZrO 3 or the like. This is considered to be the same for other alkali metal zirconates, and the above electrode reaction is reversible.

以上のように、アルカリ金属ジルコン酸塩は、結露によるマイグレーションが少なく、Liイオンなどのアルカリ金属イオンの活量を一定に保つことができ、しかもCO2との電極反応を可逆に行うことができる、電極材料と考えられる。発明者は、CO2センサの耐湿性を改善するため種々の電極材料を探索し、Li2ZrO3により著しく耐湿性を改善し得ることを発見した。そして耐湿性の改善がLi2ZrO3に限らず、Na2ZrO3等でも得られることを確認し、これらの電極反応の機構を推定した。以下に実施例を示す。 As described above, alkali metal zirconate has little migration due to condensation, can keep the activity of alkali metal ions such as Li ions constant, and can reversibly perform electrode reaction with CO 2. It is considered as an electrode material. The inventors have searched for various electrode materials to improve the moisture resistance of the CO 2 sensor and have found that the moisture resistance can be significantly improved by Li 2 ZrO 3 . And it was confirmed that the improvement of moisture resistance is not limited to Li 2 ZrO 3 but also Na 2 ZrO 3 , and the mechanism of these electrode reactions was estimated. Examples are shown below.

以下に本発明を実施するための最適実施例を示す。   In the following, an optimum embodiment for carrying out the present invention will be shown.

図１〜図７に、実施例のCO2センサとその特性を示し、図８，図９に比較例のCO2センサ（Li2ZrO3とLi2CO3の等モルの混合物）の特性を示す。図において、２はCO2センサで、ディスク上のナシコン焼結体４を備え、その組成は Na1+xZr2P3-xSixO12 で、xは0〜3で、通常は2程度である。なおナシコン中のNaイオンをLiイオンに変えたリシコンなどを用いてもよく、アルカリ金属イオン伝導体の組成は任意である。６は作用極で、例えばLi2ZrO3とAu等の貴金属との重量比で1:1の混合物からなり、８はAu等の貴金属からなる対極である。１０はヒータ基板で、ここではアルミナであり、１２はヒータで、ここではPt膜であり、他のヒータ膜でも良く、１４〜１６はリードである。１８は封止ガラスで、対極８を雰囲気から遮断するために用いる。 FIGS. 1 to 7 show the CO 2 sensor of the example and its characteristics, and FIGS. 8 and 9 show the characteristics of the CO 2 sensor of the comparative example (an equimolar mixture of Li 2 ZrO 3 and Li 2 CO 3 ). Show. In the figure, 2 is a CO 2 sensor, which has a NASICON sintered body 4 on a disk, the composition of which is Na 1 + x Zr 2 P 3-x Si x O 12 , x is 0 to 3, usually 2 Degree. Note that ricicon or the like in which Na ions in NASICON are changed to Li ions may be used, and the composition of the alkali metal ion conductor is arbitrary. 6 is a working electrode, for example, a mixture of 1: 1 by weight ratio between Li 2 ZrO 3 and a noble metal such as Au, and 8 is a counter electrode made of a noble metal such as Au. Reference numeral 10 denotes a heater substrate, which is alumina here, 12 is a heater, here is a Pt film, and may be another heater film, and 14 to 16 are leads. Reference numeral 18 denotes a sealing glass, which is used to shield the counter electrode 8 from the atmosphere.

作用極６はLi2ZrO3等とAuとの混合物からなるが、Li6Zr3O7やNa2ZrO3などと貴金属の混合物を用いてもよい。図２に作用極６を拡大して示し、作用極６はLi2ZrO3等とAuとのほぼ均一な混合物で、後述の７００℃焼成ではLi2ZrO3等はほとんど焼結しないので、通気性がある。実施例では作用極を１相で構成したが、図３のようにLi2ZrO3層上にAuなどの貴金属層２１を積層して、例えば２相で構成しても良い。作用極６中のLi2ZrO3は、Liイオンの例えば10mol%以下をNaイオンやKイオンなどの他のアルカリ金属イオンで置換しても良く、Li2ZrO3とLi2CO3との合計量を100mol%とした際に、例えば5mol%以下、好ましくは2mol%以下の割合でLi2CO3を含んでいても良い。Li2ZrO3は例えば400℃以上でCO2と可逆的に反応してLi2CO3を生成するので、Li2ZrO3の一部がLi2CO3に変化していることがある。作用極６に添加する貴金属の種類は任意である。またLi2ZrO3の分解に伴って、Li2CO3の他にZrO2を含んでいることも有り得る。 The working electrode 6 is made of a mixture of Li 2 ZrO 3 or the like and Au, but a mixture of Li 6 Zr 3 O 7 or Na 2 ZrO 3 or the like and a noble metal may be used. FIG. 2 shows the working electrode 6 in an enlarged manner. The working electrode 6 is a substantially uniform mixture of Li 2 ZrO 3 etc. and Au, and Li 2 ZrO 3 etc. hardly sinters at 700 ° C., which will be described later. There is sex. In the embodiment, the working electrode is constituted by one phase, but a noble metal layer 21 such as Au may be laminated on the Li 2 ZrO 3 layer as shown in FIG. Li 2 ZrO 3 in the working electrode 6 may replace, for example, 10 mol% or less of Li ions with other alkali metal ions such as Na ions and K ions, and the total of Li 2 ZrO 3 and Li 2 CO 3 When the amount is 100 mol%, Li 2 CO 3 may be contained, for example, in a proportion of 5 mol% or less, preferably 2 mol% or less. Li 2 ZrO 3 reacts reversibly with CO 2 at, for example, 400 ° C. or higher to produce Li 2 CO 3 , so that part of Li 2 ZrO 3 may be changed to Li 2 CO 3 . The kind of noble metal added to the working electrode 6 is arbitrary. In addition to the decomposition of Li 2 ZrO 3 , ZrO 2 may be included in addition to Li 2 CO 3 .

CO2センサ２の製造方法を説明する。作用極材料として、Li2ZrO3とAuペーストとを混合する。同様に対極材料としてAuペーストを用意し、ナシコン焼結体４を焼結する。次にヒータ１２を設けたヒータ基板１０に、対極８のAuペーストを塗布し、ナシコン焼結体４をセットし、その上部に作用極６のペーストを塗布する。次いでこれらを例えば空気中700℃で1時間焼成し、熱圧着などによりリード１４〜１６を取り付ける。その後、封止ガラス１８を塗布し、再度600℃で30分間空気中で焼成して封止する。 A method for manufacturing the CO 2 sensor 2 will be described. Li 2 ZrO 3 and Au paste are mixed as a working electrode material. Similarly, an Au paste is prepared as a counter electrode material, and the NASICON sintered body 4 is sintered. Next, the Au paste of the counter electrode 8 is applied to the heater substrate 10 provided with the heater 12, the NASICON sintered body 4 is set, and the paste of the working electrode 6 is applied thereon. Next, these are fired at 700 ° C. in air for 1 hour, and the leads 14 to 16 are attached by thermocompression bonding or the like. Thereafter, the sealing glass 18 is applied, and again baked in air at 600 ° C. for 30 minutes for sealing.

作用極６のアルカリ金属ジルコン酸塩として、Li2ZrO3を用いたもの（実施例１）、Li6Zr2O7（実施例２）を用いたもの、Na2ZrO3（実施例３）を用いたものの３種類を調製した。またこれ以外に、Li2ZrO3とLi2CO3のモル比を98:2としたもの（実施例４）、95:5としたもの（実施例５）、1:1としたもの（比較例）を調製した。またLi2ZrO3に代えてLi2CO3を用いたもの（従来例）を調製した。 As the alkali metal zirconate of working electrode 6, one using Li 2 ZrO 3 (Example 1), one using Li 6 Zr 2 O 7 (Example 2), Na 2 ZrO 3 (Example 3) Three types were prepared using those. In addition, the molar ratio of Li 2 ZrO 3 and Li 2 CO 3 was 98: 2 (Example 4), 95: 5 (Example 5), and 1: 1 (comparison) Example) was prepared. Also those using Li 2 CO 3 in place of Li 2 ZrO 3 was prepared (a conventional example).

測定結果に付いて説明する。センサの起電力を10倍に増幅したものを出力とし、CO2 350ppm中と30000ppm中との出力の差を出力差とする。製造した各CO2センサを45℃相対湿度100%の雰囲気に非加熱放置し、時々雰囲気から取り出して30分間400℃に加熱した後、CO2 350ppm中と30000ppm中の起電力を測定した。図４〜図７に実施例の特性を、図８，図９に比較例の特性を示す。従来例の結果は図６，図７に示す。そして従来例での、フィールドテストの結果と、45℃相対湿度100%中での非加熱放置テストの結果との比較から、45℃相対湿度100%での非加熱放置は２日で、フィールドテストでの1年分程度の特性変化をもたらすことを確認した。従って45℃相対湿度100%の雰囲気で20日程度の非加熱放置に耐えることができれば、実用的には充分な耐湿性を備えていることになる。表１に、各試料の組成を示す。なお（Li2ZrO3＋Li2CO3 98:2）等は混合比をモル比で示し、AuはLi2ZrO3等と等重量添加した。試料の調製条件は共通である。 The measurement results will be described. The output obtained by amplifying the sensor's electromotive force by a factor of 10 is used as the output, and the difference in output between 350 ppm and 30000 ppm of CO 2 is the output difference. Each manufactured CO 2 sensor was left unheated in an atmosphere of 45 ° C. and 100% relative humidity, removed from the atmosphere from time to time and heated to 400 ° C. for 30 minutes, and then the electromotive force in 350 ppm of CO 2 and 30000 ppm was measured. 4 to 7 show the characteristics of the example, and FIGS. 8 and 9 show the characteristics of the comparative example. The results of the conventional example are shown in FIGS. And comparing the result of the field test in the conventional example with the result of the non-heated leaving test at 45 ° C and 100% relative humidity, the non-heated standing at 45 ° C and 100% relative humidity is 2 days. It was confirmed that the change in characteristics of about one year in Therefore, if it can withstand unheated standing for about 20 days in an atmosphere of 45 ° C. and a relative humidity of 100%, it has practically sufficient moisture resistance. Table 1 shows the composition of each sample. Note that (Li 2 ZrO 3 + Li 2 CO 3 98: 2) and the like indicate the mixing ratio in terms of molar ratio, and Au is added in an equal weight to Li 2 ZrO 3 and the like. Sample preparation conditions are common.

表 １
実施例 図 作用極の組成 サンプル数
実施例１ 図４〜図７ Li2ZrO3＋Au （1:1） ５
実施例２ 図６ Li6Zr２O7＋Au （1:1） ５
実施例３ 図６ Na6Zr２O7＋Au （1:1） ５
実施例４ 図７ （Li2ZrO3＋Li2CO3 98:2）＋Au （1:1） ５
実施例５ 図７ （Li2ZrO3＋Li2CO3 95:5）＋Au （1:1） ５

比較例 図８，図９ （Li2ZrO3＋Li2CO3 50:50）＋Au（1:1） ８
従来例 図６，図７ Li2CO3＋Au （1:1） ５ Table 1
Example Figure Working electrode composition Number of samples
Example 1 FIGS. 4 to 7 Li 2 ZrO 3 + Au (1: 1) 5
Example 2 FIG. 6 Li 6 Zr 2 O 7 + Au (1: 1) 5
Example 3 FIG. 6 Na 6 Zr 2 O 7 + Au (1: 1) 5
Example 4 FIG. 7 (Li 2 ZrO 3 + Li 2 CO 3 98: 2) + Au (1: 1) 5
Example 5 FIG. 7 (Li 2 ZrO 3 + Li 2 CO 3 95: 5) + Au (1: 1) 5

Comparative Example FIGS. 8 and 9 (Li 2 ZrO 3 + Li 2 CO 3 50:50) + Au (1: 1) 8
Conventional example Fig. 6 and Fig. 7 Li 2 CO 3 + Au (1: 1) 5

図４〜図７に実施例や従来例の結果を示す。非加熱放置に対して起電力は安定で、起電力のドリフトは緩やかである。結果はLi2ZrO3を用いたものが最良で、Li6Zr２O7がこれに次ぎ、Na6Zr２O7はLi6Zr２O7よりも劣るが、従来例よりも充分に優れている。Li2ZrO3にLi2CO3を混合すると、2モル％程度までは影響が少なく、5モル％では影響があるものの、なお優れた特性が得られる。これに対してLi2ZrO3とLi2CO3との等モル混合物では従来例と大差のない結果となった。CO2 30000ppmと350ppm間の出力差は、実施例１では当初の10日程度増加し、その後ほぼ安定化し、実施例２〜５でも類似の結果が得られた。従って10日程度この雰囲気でエージングすれば、出力も出力差も安定したCO2センサが得られる。 4 to 7 show the results of Examples and Conventional Examples. The electromotive force is stable against non-heating and the electromotive force drift is gentle. The result is best using Li 2 ZrO 3 , followed by Li 6 Zr 2 O 7 , and Na 6 Zr 2 O 7 is inferior to Li 6 Zr 2 O 7 , but much better than the conventional example. ing. Upon mixing of Li 2 ZrO 3 to Li 2 CO 3, up to about 2 mol% effect is small, although there is influence in 5 mol%, even better characteristics can be obtained. On the other hand, an equimolar mixture of Li 2 ZrO 3 and Li 2 CO 3 showed no significant difference from the conventional example. The output difference between 30000 ppm and 350 ppm of CO 2 increased for about 10 days in Example 1 and then stabilized substantially, and similar results were obtained in Examples 2 to 5. Therefore, if it is aged in this atmosphere for about 10 days, a CO 2 sensor with stable output and output difference can be obtained.

この発明では、作用極にアルカリ金属のジルコン酸塩、好ましくはNaもしくはLiのジルコン酸塩、特に好ましくはLi2ZrO3もしくはLi6Zr2O7、最も好ましくはLi2ZrO3を用いることにより、CO2センサの耐湿性を向上させる。作用極はアルカリ金属のジルコン酸塩と貴金属などの金属のみからなることが好ましく、アルカリ金属ジルコン酸塩の一部がCO2との反応により分解することを考慮しても、アルカリ金属ジルコン酸塩とアルカリ金属炭酸塩の合計を100mol%とした場合に、炭酸Liなどのアルカリ金属炭酸塩の含有量は、Li2CO3等として5mol%以下、より好ましくは2mol%以下とする。 In this invention, by using an alkali metal zirconate as the working electrode, preferably Na or Li zirconate, particularly preferably Li 2 ZrO 3 or Li 6 Zr 2 O 7 , most preferably Li 2 ZrO 3 , Improve the moisture resistance of the CO 2 sensor. The working electrode is preferably composed only of an alkali metal zirconate and a metal such as a noble metal, and even if it is considered that a part of the alkali metal zirconate is decomposed by reaction with CO 2 , the alkali metal zirconate And the alkali metal carbonate is 100 mol%, the content of alkali metal carbonate such as Li carbonate is 5 mol% or less, more preferably 2 mol% or less as Li 2 CO 3 or the like.

CO2センサの構造自体は任意で、変形例のCO2センサ８２を図１０に示す。ヒータ基板１０の一面にヒータ１２を設け、他面にナシコン膜８４を設け、その表面に作用極６と対極８とを設け、対極８を封止ガラス１８で封止する。他の点では図１〜図５の実施例と同様で、ナシコン膜８４はヒータ基板１０への印刷と焼成により調製する。
The structure of the CO 2 sensor itself is arbitrary, and a modified CO 2 sensor 82 is shown in FIG. The heater 12 is provided on one surface of the heater substrate 10, the NASICON film 84 is provided on the other surface, the working electrode 6 and the counter electrode 8 are provided on the surface, and the counter electrode 8 is sealed with the sealing glass 18. The other points are the same as those of the embodiment of FIGS. 1 to 5, and the NASICON film 84 is prepared by printing on the heater substrate 10 and baking.

実施例のCO2センサの断面図Cross-sectional view of the CO 2 sensor of the example 作用極の拡大断面図Enlarged sectional view of the working electrode 変形例の作用極の拡大断面図Enlarged sectional view of the working electrode of the modification 実施例１のCO2センサを、45℃相対湿度100%雰囲気で40日間非加熱放置した際の、CO2350ppm中の起電力を示す特性図Characteristic diagram showing electromotive force in 350 ppm of CO 2 when the CO 2 sensor of Example 1 is left unheated for 40 days in an atmosphere of 45 ° C. and 100% relative humidity 図４の条件での、実施例１でのCO23%と350ppmとの間の起電力差を示す特性図FIG. 4 is a characteristic diagram showing the electromotive force difference between 3% CO 2 and 350 ppm in Example 1 under the conditions of FIG. 実施例１（Li2ZrO3）、実施例２（Li６Zr２O７）、実施例３（Na2ZrO3）、従来例（Li2CO3）の各CO2センサを、45℃相対湿度100%雰囲気で非加熱放置した際の、CO2350ppm中の起電力を示す特性図The CO 2 sensors of Example 1 (Li 2 ZrO 3 ) , Example 2 (Li 6 Zr 2 O 7 ), Example 3 (Na 2 ZrO 3 ), and the conventional example (Li 2 CO 3 ) Characteristic diagram showing electromotive force in 350 ppm CO 2 when left unheated in a 100% humidity atmosphere 実施例１（Li2ZrO3）、実施例４（Li６Zr２O７：Li2CO3＝98:2）、実施例５（Li６Zr２O７：Li2CO3＝95:5）、従来例（Li2CO3）の各CO2センサを、45℃相対湿度100%雰囲気で非加熱放置した際の、CO2350ppm中の起電力を示す特性図Example 1 (Li 2 ZrO 3 ) , Example 4 (Li 6 Zr 2 O 7 : Li 2 CO 3 = 98: 2), Example 5 (Li 6 Zr 2 O 7 : Li 2 CO 3 = 95: 5) ) Characteristic diagram showing the electromotive force in 350 ppm of CO 2 when each CO 2 sensor of the conventional example (Li 2 CO 3 ) is left unheated at 45 ° C and 100% relative humidity. 比較例のCO2センサ（Li2ZrO3とLi2CO3の等モルの混合物）を、45℃相対湿度100%雰囲気で40日間非加熱放置した際の、CO2350ppm中の起電力を示す特性図The electromotive force in 350 ppm of CO 2 when the CO 2 sensor of the comparative example (mixture of equimolar amounts of Li 2 ZrO 3 and Li 2 CO 3 ) is left unheated for 40 days at 45 ° C and 100% relative humidity is shown. Characteristics chart 図８の条件での、比較例でのCO23%と350ppmとの間の起電力差を示す特性図Characteristic diagram showing the electromotive force difference between 3% CO 2 and 350 ppm in the comparative example under the conditions of FIG. 変形例のCO2センサの断面図Cross-sectional view of a modified CO 2 sensor

符号の説明Explanation of symbols

２，８２ CO2センサ
４ ナシコン焼結体
６ 作用極
８ 対極
１０ ヒータ基板
１２ ヒータ
１４〜１６ リード
１８ 封止ガラス
２０ Li2ZrO3層
２１ 貴金属層
８４ ナシコン膜 2,82 CO 2 sensor 4 NASICON sintered body 6 Working electrode 8 Counter electrode 10 Heater substrate 12 Heater 14-16 Lead 18 Sealing glass 20 Li 2 ZrO 3 layer 21 Noble metal layer
84 NASICON membrane

Claims (4)

アルカリイオン伝導体に接続した対極と検知極と、該アルカリイオン伝導体を加熱するヒータとを設けたCO2センサにおいて、
前記検知極が貴金属とアルカリ金属のジルコン酸塩とからなることを特徴とするCO2センサ。 In the CO 2 sensor provided with a counter electrode connected to the alkali ion conductor, a detection electrode, and a heater for heating the alkali ion conductor,
A CO 2 sensor, wherein the detection electrode comprises a noble metal and an alkali metal zirconate. 前記ジルコン酸塩がNaもしくLiのジルコン酸塩であることを特徴とする、請求項１のCO2センサ。 The CO 2 sensor according to claim 1, wherein the zirconate is Na or Li zirconate. 前記ジルコン酸塩がLi2ZrO3もしくはLi6Zr2O7であることを特徴とする、請求項２のCO2センサ。 Wherein said zirconate is Li 2 ZrO 3 or Li 6 Zr 2 O 7, CO 2 sensor according to claim 2. 前記ジルコン酸塩がLi2ZrO3であることを特徴とする、請求項３のCO2センサ。 4. The CO 2 sensor according to claim 3 , wherein the zirconate is Li 2 ZrO 3 .
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JP7389420B2 (en) 2020-05-08 2023-11-30 国立大学法人 長崎大学 Porous solid electrolyte gas sensor

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JP6330961B1 (en) * 2017-08-24 2018-05-30 株式会社ナカヨ Wireless terminal and computer readable program
JP7389420B2 (en) 2020-05-08 2023-11-30 国立大学法人 長崎大学 Porous solid electrolyte gas sensor

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