KR100767347B1 - P-type Co3O4-SnO2 composite having superior selectivity to CO over H2, and thick film and gas sensor prepared therefrom - Google Patents
P-type Co3O4-SnO2 composite having superior selectivity to CO over H2, and thick film and gas sensor prepared therefrom Download PDFInfo
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- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B17/00—Layered products essentially comprising sheet glass, or glass, slag, or like fibres
- B32B17/06—Layered products essentially comprising sheet glass, or glass, slag, or like fibres comprising glass as the main or only constituent of a layer, next to another layer of a specific material
- B32B17/10—Layered products essentially comprising sheet glass, or glass, slag, or like fibres comprising glass as the main or only constituent of a layer, next to another layer of a specific material of synthetic resin
- B32B17/10005—Layered products essentially comprising sheet glass, or glass, slag, or like fibres comprising glass as the main or only constituent of a layer, next to another layer of a specific material of synthetic resin laminated safety glass or glazing
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- B32B17/10174—Coatings of a metallic or dielectric material on a constituent layer of glass or polymer
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- G01N33/0004—Gaseous mixtures, e.g. polluted air
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Abstract
본 발명은 p-타입 Co3O4-SnO2 복합체에 관한 것이며, 구체적으로는 (i) 40-95.5 중량%의 Co3O4, (ii) 선택적으로 0.01-0.7 중량%의 Au, (iii) 나머지 함량의 SnO2를 포함하는 CO 감지용 p-타입 Co3O4-SnO2를 포함시킴으로써 H2에 대한 CO의 선택도가 매우 우수한 p-타입 Co3O4-SnO2 복합체 및 이를 이용하여 제조된 후막 및 기체센서에 관한 것이다.The present invention relates to a p-type Co 3 O 4 -SnO 2 complex, specifically (i) 40-95.5% by weight of Co 3 O 4 , (ii) optionally 0.01-0.7% by weight of Au, (iii P-type Co 3 O 4 -SnO 2 composite having excellent CO selectivity for H 2 by including p-type Co 3 O 4 -SnO 2 for CO sensing including the remaining amount of SnO 2 , and using the same It relates to a thick film and a gas sensor manufactured by.
ｐ-타입 Ｃｏ3Ｏ4-ＳｎＯ2 복합체, 후막, 기체센서 ｐ-type CO3O4-SnO2 composite, thick film, gas sensor
Description
도1은 본 발명의 여러 구현예에 따른 복합체의 입도 및 비표면적을 도시한 그래프이다.1 is a graph showing the particle size and specific surface area of a composite according to various embodiments of the present invention.
도2는 본 발명의 여러 구현예에 따른 복합체 또는 센서의 공기 중 저항 및 CO 중 저항을 도시한 그래프이다.2 is a graph illustrating resistance in air and resistance in CO of a composite or sensor according to various embodiments of the present disclosure.
도3은 본 발명의 여러 구현예에 따른 복합체 또는 센서의 Co3O4 함량에 따른 CO에 대한 센서응답을 나타낸 그래프이다.Figure 3 is a graph showing the sensor response to the CO according to the Co 3 O 4 content of the composite or sensor according to various embodiments of the present invention.
도4는 본 발명의 여러 구현예에 따른 복합체 또는 센서의 Co3O4 함량에 따른 H2에 대한 센서응답을 나타낸 그래프이다.Figure 4 is a graph showing the sensor response to H 2 according to the Co 3 O 4 content of the composite or sensor according to various embodiments of the present invention.
도5는 본 발명의 구현예에 따른 복합체 및 후막에 대한 다양한 CO 농도에서의 센서응답을 나타낸 그래프이다.Figure 5 is a graph showing the sensor response at various CO concentrations for the composite and thick film according to an embodiment of the present invention.
도6 및 도7은 CO 또는 H2의 감지물성을 나타낸 그래프이다.6 and 7 are graphs showing sensing properties of CO or H 2 .
도8은 CO에 대한 응답 과도특성을 나타낸 그래프이다.8 is a graph showing the response transient characteristics for CO.
종래 SnO2, WO3, ZnO, TiO2와 같은 금속산화물은 특정 기체를 감지하는 센서에 사용되어 왔다. 특히 SnO2 계열의 센서는 저온의 작동온도에서 비교적 높은 감응성(sensitivity)을 보이는 것으로 알려져 있으며, 산화성 기체(reducing gas)를 감지하는데 널리 사용되어 왔다.Conventionally, metal oxides such as SnO 2 , WO 3 , ZnO, TiO 2 have been used in sensors for detecting specific gases. In particular, SnO 2 series sensors are known to exhibit relatively high sensitivity at low operating temperatures, and have been widely used to detect oxidizing gases.
그러나 기체에 대한 낮은 선택도(selectivity)가 일반적으로 문제가 되어, SnO2, In2O3 등 다양한 금속산화물 계열 기체 센서에 소량의 부가물을 첨가하여 센서의 민감도뿐만 아니라 선택도를 높이려는 시도들이 있어왔다.However, low selectivity to gases is generally a problem, and there have been attempts to increase the selectivity as well as the sensitivity of the sensor by adding small amounts of additives to various metal oxide based gas sensors such as SnO 2 and In 2 O 3. .
특히 각 성분의 물성을 유지하면서 전체적인 감지특성을 향상시키기 위해서 벌크 및 표면의 전기적 구조를 변화시키는 노력으로 복합체 산화물이 시도되어 왔다. 그 중에서도 CO에 대한 선택성을 증가시키기 위하여 반도체 산화물의 다양한 이종계면(heterogeneous interfaces)이 다음과 같이 제시되어 왔다.In particular, complex oxides have been tried in an effort to change bulk and surface electrical structures in order to improve overall sensing characteristics while maintaining physical properties of each component. Among them, various heterogeneous interfaces of semiconductor oxides have been proposed as follows to increase the selectivity to CO.
W. Y. Chung 등[Thin Solid Films, 221 (1992) 304-310]과 M. Zakrzewska 등[Thin Solid Films, 310 (1997) 161-166]은 SnO2-TiO2를 제시하였으며; J. L. Solis 등[Sens. Actuators B, 24/25 (1995) 591; Physica Scripta, T69 (197) 281] 은 SnO2-WO3를 제시하였으며; P. Nelli 등[Sens. Actuators B, 31 (1996) 89-91]과 L. E. Depero 등[Sens. Actuators B, 35/36 (1996) 381-383]은 TiO2-WO3를 제시하였으며; K. Zakrzewska 등[Thin Solid Films, 391 (2001) 29-238]은 ZnO-SnO2을 제시하였으며; X. Zhou 등[Mat. Sci. Eng., B99 (2003) 44-47]은 CuO-SnO2를 제시하였고; S. T. Jun 등[Sens. Actuators B, 17 (1986) 413-416]은 CuO-ZnO를 제시하였다.WY Chung et al. [Thin Solid Films, 221 (1992) 304-310] and M. Zakrzewska et al. [Thin Solid Films, 310 (1997) 161-166] presented SnO 2 -TiO 2 ; JL Solis et al. [Sens. Actuators B, 24/25 (1995) 591; Physica Scripta, T69 (197) 281 presented SnO 2 -WO 3 ; P. Nelli et al. [Sens. Actuators B, 31 (1996) 89-91 and LE Depero et al. [Sens. Actuators B, 35/36 (1996) 381-383, present TiO 2 -WO 3 ; K. Zakrzewska et al. [Thin Solid Films, 391 (2001) 29-238] presented ZnO-SnO 2 ; X. Zhou et al. [Mat. Sci. Eng., B99 (2003) 44-47, present CuO-SnO 2 ; ST Jun et al. Actuators B, 17 (1986) 413-416, present CuO-ZnO.
이 중에서 SnO2 및 TiO2는 n-타입 반도체로서 비슷한 원자구조 및 전자구조를 보인다. 혼합 산화물 SnO2-TiO2 시스템은 구조적 유사성 및 기체 감지물성을 조사하기 위해서 사용되었다.Among them, SnO 2 and TiO 2 are n-type semiconductors, which show similar atomic and electronic structures. Mixed oxide SnO 2 -TiO 2 systems were used to investigate structural similarity and gas sensing properties.
기타 종래의 금속 산화물 기체 센서는 다음의 표1에 나타낸 바와 같다.Other conventional metal oxide gas sensors are shown in Table 1 below.
그러나 이러한 종래의 시도들에도 불구하고 센서의 민감도 및 선택도 향상효과에 있어 그리 만족할 만한 결과를 보이지 못하였다.However, despite these previous attempts, the sensor did not show satisfactory results in improving sensitivity and selectivity.
또한, 기체 센서의 제조방법에 대해서도 많은 시도들이 있어왔는데, 감지물성을 향상시키기 위해서 박막, 후막, 졸-겔법과 같은 방법들이 보고 되어왔다 [Kane 등, J. Electrochem. Soc., 123 (1976) 270; R.D. Tarey 등, Thin Solid Films, 128 (1985) 181-189; D. W. Lane 등, Thin Solid Films, 221 (1992) 262; J. C. Manifacier, Mater. Res. Bull., 24 (1979) 163); M. Miki-Yoshida 등, Thin Solid Films, 224 (1993) 97-96; A. K. Kukarni 등, Thin Solid Films, 220 (1992) 321; T. Karasawa 등, Thin Solid Films, 223 (1993) 135-139; P. T. Moseley, Sens. Actuators B, 3 (1991) 167-174].In addition, many attempts have been made on the method of manufacturing a gas sensor, and methods such as a thin film, a thick film, and a sol-gel method have been reported to improve sensing properties [Kane et al., J. Electrochem. Soc., 123 (1976) 270; R.D. Tarey et al., Thin Solid Films, 128 (1985) 181-189; D. W. Lane et al., Thin Solid Films, 221 (1992) 262; J. C. Manifacier, Mater. Res. Bull., 24 (1979) 163); M. Miki-Yoshida et al., Thin Solid Films, 224 (1993) 97-96; A. K. Kukarni et al., Thin Solid Films, 220 (1992) 321; T. Karasawa et al., Thin Solid Films, 223 (1993) 135-139; P. T. Moseley, Sens. Actuators B, 3 (1991) 167-174.
그 중에서도 박막 센서는 CVD, r.f. 스퍼터링, 딥코팅, 스핀코팅과 같은 건식법 또는 습식법에 의해서 제조된다. 또한, 후막 센서는 센서 물질의 페이스트를 기재 위에 스크린 프린팅하여 제조되는데, 이러한 방법은 반응성 및 분산성을 정밀학 조절할 수 있는 단점이 있으나 상이한 물질을 적층하는데 적당하지 않은 단점이 있다.Among them, the thin film sensor is CVD, r.f. It is manufactured by dry or wet methods such as sputtering, dip coating and spin coating. In addition, the thick film sensor is manufactured by screen printing a paste of the sensor material on a substrate. This method has a disadvantage in that the reactivity and dispersibility can be precisely controlled, but is not suitable for laminating different materials.
따라서 본 발명은 종래 기술의 문제점을 해결하기 위하여, SnO2-Co3O4의 복합체를 구성함으로써 CO 또는 H2에 대한 민감도 및 선택도가 크게 향상된 SnO2-Co3O4 복합체 및 이를 이용한 후막 및 기체센서를 제공한다.Thus, the present invention is to solve the problems of the prior art, SnO 2 by forming a complex of -Co 3 O 4, the sensitivity and selectivity of the CO or H 2 is also significantly improved SnO 2 -Co 3 O 4, and the composite thick film using the same. And a gas sensor.
본 발명이 일 측면은 (i) 40-95.5 중량%의 Co3O4, 및 (ii) 나머지 함량의 SnO2를 포함하는 CO 감지용 p-타입 Co3O4-SnO2 복합체에 관한 것이다.One aspect of the present invention relates to a p-type Co 3 O 4 -SnO 2 complex for CO sensing comprising (i) 40-95.5% by weight of Co 3 O 4 , and (ii) the remaining content of SnO 2 .
n-타입 센서응답은 환원성 기체에 노출되었을 때의 전기저항(Rg)의 값이 공기 중 저항(Ra)에 비하여 감소하는 경향을 보이는 반면, p-타입 센서응답은 Ra에 비하여 Rg의 값이 오히려 증가하는 경향을 보이게 된다.The n-type sensor response tends to decrease the value of the electrical resistance (R g ) when exposed to reducing gas compared to the resistance in air (R a ), whereas the p-type sensor response is R g compared to R a . R value tends to increase.
본 발명의 바람직한 일 측면은 (i) 45-55 중량%의 Co3O4, 및 (ii) 나머지 함량의 SnO2를 포함하는 CO 감지용 p-타입 Co3O4-SnO2 복합체에 관한 것이며, 더욱 바람직한 일 측면은 (i) 50 중량%의 Co3O4, 및 (ii) 나머지 함량의 SnO2를 포함하는 CO 감지용 p-타입 Co3O4-SnO2 복합체이다.One preferred aspect of the invention relates to a p-type Co 3 O 4 -SnO 2 composite for CO sensing comprising (i) 45-55 wt.% Co 3 O 4 , and (ii) the remaining content of SnO 2 . , A more preferred aspect is a p-type Co 3 O 4 -SnO 2 composite for CO sensing comprising (i) 50 wt% Co 3 O 4 , and (ii) the remaining content of SnO 2 .
본 발명의 다른 측면은 (i) 45-55 중량%의 Co3O4, (ii) 0.01-0.7 중량%의 Au, 및 (iii) 나머지 함량의 SnO2를 포함하는 CO 감지용 p-타입 Co3O4-SnO2 복합체에 관한 것이다.Another aspect of the invention is a p-type Co for CO sensing comprising (i) 45-55 wt.% Co 3 O 4 , (ii) 0.01-0.7 wt.% Au, and (iii) SnO 2 in the remainder. It relates to a 3 O 4 -SnO 2 complex.
본 발명의 바람직한 다른 측면은 (i) 45-55 중량%의 Co3O4, (ii) 0.045-0.55 중량%의 Au, 및 (iii) 나머지 함량의 SnO2를 포함하는 CO 감지용 p-타입 Co3O4-SnO2 복합체에 관한 것이다.Another preferred aspect of the present invention is a p-type for CO sensing comprising (i) 45-55 wt% Co 3 O 4 , (ii) 0.045-0.55 wt% Au, and (iii) SnO 2 in the remaining content. It relates to a Co 3 O 4 -SnO 2 complex.
위에서 Co3O4의 함량이 위의 범위를 벗어나는 경우에 각각 감도 및 선택성이 감소하는 경향이 발생할 수 있다. 또한 Au의 함량이 위의 범위를 벗어나는 경우에는 각각 감도 및 선택성이 감소하는 경향이 발생할 수 있다.When the content of Co 3 O 4 in the above is out of the above range may tend to decrease the sensitivity and selectivity, respectively. In addition, when the Au content is out of the above range, the sensitivity and selectivity may respectively decrease.
한편 본 발명은 위에서 제조한 Co3O4-SnO2 복합체를 이용하여 제조한 CO 감지용 p-타입 Co3O4-SnO2 복합체 후막에 관한 것이다.Meanwhile, the present invention relates to a p-type Co 3 O 4 -SnO 2 composite thick film for detecting CO prepared using the Co 3 O 4 -SnO 2 composite prepared above.
또한 본 발명은 위에서 제조한 Co3O4-SnO2 복합체를 포함하는 CO 감지용 p-타입 Co3O4-SnO2 복합체 센서에 관한 것이다.The present invention also relates to a p-type Co 3 O 4 -SnO 2 complex sensor for detecting CO, including the Co 3 O 4 -SnO 2 complex prepared above.
이하의 실시예 등은 본 발명을 보다 구체적으로 설명하기 위함이며, 본 발명은 이에 한정되지 않는다.The following examples and the like are intended to explain the present invention in more detail, but the present invention is not limited thereto.
실시예Example
본원에서 사용되는 'SCx'는 SnO2 및 Co3O4가 (100-x)중량% : x중량%로 혼합하여 제조된 복합체 또는 소결체를 의미한다.'SCx' as used herein refers to a composite or sintered body prepared by mixing SnO 2 and Co 3 O 4 at (100-x) wt%: x wt%.
실시예 I: CoExample I: Co 33 OO 44 첨가의 효과 관찰 Observe the effect of the addition
제조예1-2: SnO2 분말 및 Co3O4 분말의 제조 Preparation Example 1-2 Preparation of SnO 2 Powder and Co 3 O 4 Powder
KOJUNDO Chemicals의 시약등급인 SnCl4·xH2O에 암모니아 수용액 및 탈이온수를 현탁액의 pH가 7~9가 될 때까지 교반하면서 첨가하였다. 침전물을 실온에서 24시간 동안 보관한 후 여과하고 나서 탈이온수 및 에틸알코올로 세척하였다. 세척된 침전물을 120℃에서 건조한 후 제분하고 나서, 550-600℃에서 2 시간 동안 하소시킴으로써, SnO2 분말을 수득하였다.Aqueous ammonia and deionized water were added to SnCl 4 .xH 2 O, a reagent grade of KOJUNDO Chemicals, with stirring until the pH of the suspension reached 7-9. The precipitate was stored at room temperature for 24 hours and then filtered and washed with deionized water and ethyl alcohol. The washed precipitate was dried at 120 ° C. and then milled and then calcined at 550-600 ° C. for 2 hours to obtain SnO 2 powder.
또한 Co3O4에 대해서도 위와 동일한 방법으로 제조하되, SnCl4·xH2O 대신에 Co(NO3)2·6H2O을 이용함으로써 Co3O4 분말을 수득하였다.Co 3 O 4 was also prepared in the same manner as above, but Co 3 O 4 powder was obtained by using Co (NO 3) 2. 6H 2 O instead of SnCl 4 .xH 2 O.
실시예1: SC50 복합체 및 SC50 후막의 제조 Example 1 Preparation of SC50 Complex and SC50 Thick Film
SnO2 분말 및 Co3O4 분말을 50중량% : 50중량% 비율로 혼합한 후, 24시간 동안 볼밀링을 수행하고 나서 120℃에서 12시간 동안 건조시킴으로써 SC0.5를 수득하였다. 제조된 SC0.5 복합체를 α-테르피네올(95%)-에틸셀룰로오스(5%) 분산액과 혼합하고 나서 interdegited Au 전극이 부착된 알루미나 기재(substrate)에 스크린 프린팅한 후, 700℃에서 3시간 동안 소결시킴으로써(sintering) SC50 복합체 후막(thick film)을 제조하였다.SC0.5 was obtained by mixing SnO 2 powder and Co 3 O 4 powder in a 50 wt%: 50 wt% ratio, followed by ball milling for 24 hours and drying at 120 ° C. for 12 hours. The prepared SC0.5 composite was mixed with α-terpineol (95%)-ethylcellulose (5%) dispersion and screen printed on an alumina substrate having an interdegited Au electrode attached thereto, followed by 3 hours at 700 ° C. SC50 composite thick film was prepared by sintering.
또한 실시예1과 동일한 방법으로 제조하되, 복합체의 전체 중량을 기준으로 Co3O4 분말의 중량을 1중량%, 3중량%, 5중량%로 혼합시킴으로써 각각 SC1, SC3, SC5 복합체를 수득하였다. 또한 이를 이용하여 실시예1과 동일한 방법으로 각각 SC1, SC3, SC5 복합체 후막을 제조하였다.Also prepared in the same manner as in Example 1, by mixing the weight of the Co 3 O 4 powder in 1% by weight, 3% by weight, 5% by weight based on the total weight of the composite to obtain a SC1, SC3, SC5 composite, respectively . In addition, by using the same method as in Example 1 SC1, SC3, SC5 composite thick film was prepared respectively.
실시예2: SC75 복합체 및 SC75 후막의 제조 Example 2 Preparation of SC75 Complex and SC75 Thick Film
실시예1과 동일한 방법으로 제조하되, SnO2 분말 및 Co3O4 분말을 25중량% : 75중량% 비율로 사용함으로써 SC75 복합체 및 SC75 복합체 후막을 제조하였다.Prepared in the same manner as in Example 1, by using a SnO 2 powder and Co 3 O 4 powder in a 25% by weight: 75% by weight ratio SC75 composite and SC75 composite thick film was prepared.
비교예1-6: p-타입 SCx 복합체 및 SCx 후막의 제조 Comparative Example 1-6 : Preparation of p-type SCx Complex and SCx Thick Film
실시예1과 동일한 방법으로 제조하되, Co3O4의 함량을 25중량%, 90중량%, 95중량%, 97중량%, 99중량%, 100중량%로 변화시켜 각각 SC25, SC90, SC95, SC97, SC99, SC100 복합체 또는 소결체를 얻었고, 이를 이용하여 이들의 후막을 제조하였다.Prepared in the same manner as in Example 1, by changing the content of Co 3 O 4 25%, 90%, 95%, 97%, 99%, 100% by weight of SC25, SC90, SC95, SC97, SC99, SC100 composites or sintered bodies were obtained, and their thick films were prepared using them.
비교예7-12: n-타입 SCx 복합체 및 SCx 후막의 제조 Comparative Example 7-12 Preparation of n-type SCx Complex and SCx Thick Film
실시예1과 동일한 방법으로 제조하되, Co3O4 분말의 함량을 0중량%, 0.5중량%, 1중량%, 3중량%, 5중량%, 10중량%로 변화시켜 각각 SC0, SC0.5, SC1, SC3, SC5, SC10 복합체 또는 소결체를 얻었고, 이를 이용하여 이들의 후막을 제조하였다.Manufactured in the same manner as in Example 1, except that the content of Co 3 O 4 powder was changed to 0 wt%, 0.5 wt%, 1 wt%, 3 wt%, 5 wt%, and 10 wt%, respectively, SC0 and SC0.5. , SC1, SC3, SC5, SC10 composites or sintered bodies were obtained, and their thick films were prepared using them.
실험예1: D 및 SSA의 측정 Experimental Example 1 Measurement of D and SSA
실시예 및 비교예에서 제조한 SCx 복합체 또는 소결체에 대해서 X선회절분석을 수행하여 얻은 X선 회절 패턴의 SnO2(110) 피크 및 Co3O4(311) 피크로부터 반높이너비(full width at half maximum; 'FWHM')를 측정하여 이로부터 SnO2 및 Co3O4의 입도(grain size; 'D')를 구하였으며, 또한 각각에 대해서 BET법을 이용하여 각각의 복합체의 비표면적(specific surface area; 'SSA')을 측정하여, 도1와 같은 결과를 얻었다.Full width at half width from the SnO 2 (110) peak and the Co 3 O 4 (311) peak of the X-ray diffraction pattern obtained by performing X-ray diffraction analysis on the SCx composites or the sintered bodies prepared in Examples and Comparative Examples The half maximum ('FWHM') was measured to obtain the grain size (D) of SnO 2 and Co 3 O 4 , and the specific surface area of each composite was determined using the BET method. surface area ('SSA') was measured to obtain a result as shown in FIG.
Co3O4이 소량 함유된 n-타입 복합체의 경우에 Co3O4를 첨가함에 따라서 SnO2의 D값이 크게 감소하는 것과는 달리, Co3O4의 D는 SC50에서 SC100에 이르기까지 32-42nm로 안정적임을 알 수 있으며, 이는 SSA가 단순 감소하고 있는 경향과 부합하는 결과이다.Unlike Co 3 O 4, this D value of SnO 2 significantly decreased as the addition of Co 3 O 4 in the case of a small amount of a complex containing n- type, D of Co 3 O 4 is 32 at SC50 through to SC100 It can be seen that it is stable at 42nm, which is in line with the trend of simply decreasing SSA.
실험예2: 센서의 감지물성(sensing property) 측정 Experimental Example 2 Measurement of Sensing Properties of Sensors
(1) CO 중 Ra 및 Rg의 측정(1) Determination of R a and R g in CO
상기 실시예 및 비교예에서 제조한 SCx에 대해서 공기 중 저항(Ra) 및 1,000 ppm CO 중 저항 (Rg)을 여러 온도에서 각각 측정하여 도2에 나타내었다. 또한 1,000 ppm H2 중의 저항에 대해서도 위와 동일하게 측정하였다.For the SCx prepared in Examples and Comparative Examples, the resistance in air (R a ) and the resistance in 1,000 ppm CO (R g ) were measured at various temperatures, respectively, and are shown in FIG. 2. In addition, the resistance in 1,000 ppm H 2 was measured in the same manner as above.
Co3O4의 함량이 5중량% 미만인 복합체는 200℃ 이상의 온도에서, 환원성 기체에 노출되었을 때 전기저항(Rg)의 값이 공기 중 저항(Ra)에 비하여 감소하는 n-타입의 센서응답을 보이고 있음을 확인할 수 있다. 반면 p-타입의 센서응답은 Co3O4의 함량이 25중량% 이상인 복합체에 대해서 200℃ 미만의 온도에서 나타나고 있음을 알 수 있다.Composites with a Co 3 O 4 content of less than 5% by weight have an n-type sensor whose electrical resistance (R g ) decreases compared to the air resistance (R a ) when exposed to reducing gases at temperatures above 200 ° C. You can see that the response is showing. On the other hand, it can be seen that the p-type sensor response appears at a temperature of less than 200 ° C. for the composite having a Co 3 O 4 content of 25% by weight or more.
(2) Co3O4의 함량에 따른 센서응답 관찰(2) Observation of sensor response according to the content of Co 3 O 4
위에서 얻은 온도별 Ra 및 Rg의 데이터를 이용하여 특히 100℃ 및 250℃에서 1,000 ppm CO에 대한 센서응답('Ra/Rg' 또는 'Rg/Ra')을 구하여 Co3O4 함량에 따라서 도3에 도시하였다. 또한 1,000 ppm H2에 대해서도 100℃ 및 250℃에서의 센서응답을 Co3O4 함량에 따라서 도시하여 도4에 나타내었다. n-타입의 센서응답과는 달리 Co3O4의 함량에 따른 센서응답의 변화가 완만한 것을 확인할 수 있다.Using the temperature-dependent data of R a and R g obtained above, the sensor response ('R a / R g ' or 'R g / R a ') for 1,000 ppm CO, especially at 100 ° C and 250 ° C, is obtained and Co 3 O 4 is shown according to the content. Also, the sensor response at 100 ° C. and 250 ° C. for 1,000 ppm H 2 is shown in FIG. 4 according to the Co 3 O 4 content. Unlike the n-type sensor response, it can be seen that the change in the sensor response according to the content of Co 3 O 4 is gentle.
실험예3: 민감도 및 선택도 관찰 Experimental Example 3 Observation of Sensitivity and Selectivity
(1) 민감도(sensitivity) 관찰(1) Sensitivity observation
특히 SC50에 대해서 다양한 CO 농도에서의 센서응답을 측정하였으며, 그 결과를 도5에 나타내었다. 10 ppm CO에 대해서 8.5의 센서를 보여 극히 낮은 농도 의 CO에 대해서도 감지할 수 있는 민감성을 지니고 있음을 확인할 수 있다.In particular, sensor responses at various CO concentrations were measured for SC50, and the results are shown in FIG. The 8.5 sensor for 10 ppm CO shows a sensitivity that can be detected even for very low concentrations of CO.
(2) 선택도(selectivity) 관찰(2) Observation of selectivity
또한, 다음의 표2에 1,000 ppm의 CO 및 1,000 ppm의 H2에 대한 감지특성을 나타내었다.In addition, Table 2 shows the detection characteristics for 1,000 ppm CO and 1,000 ppm H 2 .
위 표2에서 응답비(CO/H2)는 센서가 H2에 비해서 CO에 얼마나 민감하게 응답하는가를 보여주는 수치이다. 위에서 보는 바와 같이, SC50~SC95에서 매우 높은 CO에 대한 선택도를 나타냄을 확인할 수 있다. 특히 SC50의 경우 SC100에 비해 CO에 대한 선택도가 3.5배나 증가한 결과를 얻을 수 있었다.In the above Table 2, the response ratio (CO / H2) is a value that shows whether the sensor is sensitive to how the response to CO as compared to H 2. As seen above, it can be seen that the selectivity for very high CO in SC50 ~ SC95. In particular, in the case of SC50, the selectivity for CO was increased by 3.5 times compared to SC100.
실시예 II: Au 첨가의 효과 관찰Example II: Observation of the Effect of Au Addition
실시예3: SC50+Au(0.05%) 복합체, 후막의 제조 Example 3 Preparation of SC50 + Au (0.05%) Complex, Thick Film
사용된 Au 분산액은 Toda Kogyo 사의 Au 콜로이드 분산액(Au 함량: 2.0 mmol/L; Au 평균직경: ~ 9.6 nm)이다. 실시예1에서 얻은 SC50 복합체 2g을 탈이온수 200 cm3에 분산시키고, 0.05 중량%의 Au 콜로이드 분산액을 교반하면서 투입하였다. 2시간 동안 추가로 교반하고 나서 120℃에서 건조한 후 제분함으로써 SC50+Au(0.05%) 복합체를 수득하였다. 또한 이를 이용하여 실시예1과 동일한 방법으로 후막을 제조하였다.The Au dispersion used was an Au colloidal dispersion (Au content: 2.0 mmol / L; Au average diameter: 9.6 nm) from Toda Kogyo. 2 g of the SC50 composite obtained in Example 1 was dispersed in 200 cm 3 of deionized water, and 0.05 wt% Au colloidal dispersion was added with stirring. Further stirring for 2 hours followed by drying at 120 ° C. and milling yielded an SC50 + Au (0.05%) complex. In addition, a thick film was prepared in the same manner as in Example 1 using the same.
실시예4: SC50+Au(0.5%) 복합체, 후막의 제조 Example 4 Preparation of SC50 + Au (0.5%) Complex, Thick Film
Au 콜로이드 분산액을 0.05 중량% 사용하는 대신에 0.5 중량%를 사용하여 실시예3과 동일한 방법으로 SC50+Au(0.5%) 복합체를 얻고 난 후, 이를 이용하여 후막을 제조하였다.Instead of using 0.05 wt% of Au colloidal dispersion, 0.5 wt% was used to obtain the SC50 + Au (0.5%) complex in the same manner as in Example 3, and then a thick film was prepared using the same.
비교예7: SC50 복합체, 후막의 제조 Comparative Example 7 : Preparation of SC50 composite, thick film
Au 투입에 따른 정확한 비교를 위하여, 실시예3에서 Au 분산액을 투입하는 단계를 제외한 공정을 추가로 수행하여 SC50 복합체 및 이의 후막을 제조하였다.For accurate comparison according to the addition of Au, the SC50 complex and its thick film were prepared by further performing a process except adding the Au dispersion in Example 3.
비교예8: SC1+Au(0.1%) 복합체, 후막의 제조 Comparative Example 8 : Preparation of SC1 + Au (0.1%) complex, thick film
Au 콜로이드 분산액을 0.1 중량% 사용하여 실시예3과 동일한 방법으로 SC50+Au(0.1%) 복합체 및 후막을 제조하였다.SC50 + Au (0.1%) complex and thick film were prepared in the same manner as in Example 3, using 0.1 wt% of Au colloidal dispersion.
실험예4: CO 감지물성, H2 감지물성 측정 Experimental Example 4 Measurement of CO Sensitive Properties and H 2 Sensitive Properties
실시예3,4 및 비교예7,8에서 제조한 복합체 및 후막에 대해서 위 실험예와 동일한 방법으로 CO 감지물성 및 H2 감지물성을 측정하여 각각 도6 및 도7에 나타내었다.The composite materials and thick films prepared in Examples 3 and 4 and Comparative Examples 7 and 8 were measured in the same manner as in the above experimental example, and the CO and physical properties of H 2 were measured and shown in FIGS. 6 and 7, respectively.
CO 센서응답의 경우 Au가 0.05중량% 및 0.5중량% 포함됨에 따라서 증가하는 반면 0.1중량% 투입되는 경우 센서응답은 오히려 감소하는 것을 확인하였다. 또한 H2 센서응답의 경우에도 센서응답이 Au가 0.05중량% 및 0.5중량% 포함됨에 따라서 다소 증가하는 경향을 확인할 수 있었다.In the case of CO sensor response, Au was increased as 0.05 wt% and 0.5 wt% were included, whereas when 0.1 wt% was added, the sensor response was found to decrease. In addition, even in the case of the H 2 sensor response, the sensor response was found to increase slightly as 0.05 wt% and 0.5 wt% of Au were included.
실험예 5: 응답 과도특성(transient characteristics) 관찰 Experimental Example 5 Observation of Transient Characteristics
실시예3,4 및 비교예7,8에서 제조한 복합체 및 후막에 대해서 1,000 ppm의 CO에 대한 응답 과도특성을 100℃에서 관찰하여 그 결과를 도8에 나타내었다. Au가 0.05중량% 및 0.5중량% 포함되었을 때 응답 과도특성이 향상되는 결과를 확인할 수 있다.For the composites and thick films prepared in Examples 3 and 4 and Comparative Examples 7, 8, the response transient characteristics of 1,000 ppm of CO were observed at 100 ° C., and the results are shown in FIG. 8. When the Au content is 0.05% by weight and 0.5% by weight it can be confirmed that the response transient characteristics are improved.
위에서 살펴본 바와 같이 본 발명은 p-타입 Co3O4-SnO2 복합체 및 이를 이용 한 후막 및 기체센서에 관한 것으로서, 구체적으로는 (i) 40-95.5 중량%의 Co3O4, (ii) 선택적으로 0.01-0.7 중량%의 Au, (iii) 나머지 함량의 SnO2를 포함하는 CO 감지용 p-타입 Co3O4-SnO2를 포함시킴으로써 H2에 대한 CO의 민감도가 크게 향상된 결과를 확인할 수 있었다.As described above, the present invention relates to a p-type Co 3 O 4 -SnO 2 complex and a thick film and a gas sensor using the same, and specifically, (i) 40-95.5 wt% of Co 3 O 4 , (ii) As a result, the sensitivity of CO to H 2 was significantly improved by including p-type Co 3 O 4 -SnO 2 for CO detection, optionally including 0.01-0.7 wt% Au and (iii) the remaining amount of SnO 2 . Could.
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| JPS5822947A (en) | 1981-08-03 | 1983-02-10 | Yazaki Corp | Gas sensor using sno2 group |
| KR20020031439A (en) * | 2000-10-20 | 2002-05-02 | 정명식 | Gas sensor having good sensitivity and selectivity to carbon monoxide gas and process for the preparation thereof |
| KR20020037185A (en) * | 2000-11-13 | 2002-05-18 | 정명식 | Gas sensor having good sensitivity and selectivity and process for the preparation thereof |
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| JPS5822947A (en) | 1981-08-03 | 1983-02-10 | Yazaki Corp | Gas sensor using sno2 group |
| KR20020031439A (en) * | 2000-10-20 | 2002-05-02 | 정명식 | Gas sensor having good sensitivity and selectivity to carbon monoxide gas and process for the preparation thereof |
| KR20020037185A (en) * | 2000-11-13 | 2002-05-18 | 정명식 | Gas sensor having good sensitivity and selectivity and process for the preparation thereof |
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