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Bashkirov, L. A.; Chebotar, O.A.; Zharskii, I. M.; Shishkin, N.Y.; Petrov, G. S.; Nekrashevich, E. M.; Solovykh, T. K.; Akimov, A. I.

doi:10.1023/a:1015174409964

Cited by 2 publications

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“…Applications of PTCR effect include self-controlling heaters, current limiters, TV degausses and oxygen and temperature sensors. La 3+ doped BaTiO 3 ceramics sintered in air or oxidizing atmosphere show PTCR effect and are useful as CO gas sensors [22]. Compositions in the system BaTi 1−x Sn x O 3 are solid solution of barium titanate and barium stannate.…”

Section: Introductionmentioning

confidence: 99%

Structural and relaxor behavior of (Ba1−xLax)(Ti0.85Sn0.15)O3 ceramics obtained by solid state reaction

Singh

Kumar

2010

Journal of Alloys and Compounds

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Section: Introductionmentioning

confidence: 99%

Structural and relaxor behavior of (Ba1−xLax)(Ti0.85Sn0.15)O3 ceramics obtained by solid state reaction

Singh

Kumar

2010

Journal of Alloys and Compounds

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“…Therefore, much research has been conducted to enhance not only the sensitivity but also the selectivity of CO gas sensors based on semiconducting oxides and solid electrolytes. [1][2][3][4][5][6][7][8][9][10][11][12][13] However, a more serious problem, which various types of the CO gas sensors have so far suffered from, is the lack of longterm stability of these gas-sensing properties, e.g., a long-term drift in the sensor resistance for a constant concentration of CO. It usually takes at least a few hundred days to recognize such an undesirable phenomenon, 14 thus this situation makes it difficult to develop the best way to resolve this problem.…”

mentioning

confidence: 99%

Effects of Thiourea Treatment on the Sensing Properties and Stability of SnO[sub 2]-Based CO Gas Sensors

Ozaki

Suzuki

Morimitsu

et al. 2000

J. Electrochem. Soc.

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The need for a sensor to detect highly poisonous carbon monoxide, which can build up by the incomplete combustion of inflammable gases such as methane, has recently increased in order to prevent CO gas poisoning accidents in confined spaces of not only domestic and industrial premises but also recreational vehicles. The sensor for this purpose is required to detect low-level concentrations of CO in the presence of interfering gases such as H 2 which are also generated by incomplete combustion. Therefore, much research has been conducted to enhance not only the sensitivity but also the selectivity of CO gas sensors based on semiconducting oxides and solid electrolytes. 1-13 However, a more serious problem, which various types of the CO gas sensors have so far suffered from, is the lack of longterm stability of these gas-sensing properties, e.g., a long-term drift in the sensor resistance for a constant concentration of CO. It usually takes at least a few hundred days to recognize such an undesirable phenomenon, 14 thus this situation makes it difficult to develop the best way to resolve this problem.In the course of developing highly stable CO gas sensors, we have investigated a SnO 2 -based semiconductor sensor, giving special attention to the surface modification of the sintered ceramic by impregnation methods using various kinds of aqueous solutions, i.e., simple acidic media such as sulfuric acid and those dissolving sulfates, nitrates, and S-containing or N-containing organic compounds. As a consequence, it has been revealed that the sintered SnO 2 sensor element treated with a thiourea solution has an excellent gas-sensing stability for long-term operation. This paper reports these findings along with the dependence of the sensing properties on the thiourea concentration.Experimental A SnO 2 powder containing 2 wt % Pd was prepared in the same manner as previously described. 15 The powders were mixed with the same amount of alpha-alumina particles (99.9% purity, 10 m avg diam), and then a small amount of water was added to the mixture to make a paste. A sensor element was fabricated from the paste using two Ir-Pd alloy coils, then air dried for 24 h, and heated at 600ЊC for 5 min. The configuration of the sensor element was the same as that shown before. 16 The coils functioned as both heaters and electrodes. The thiourea treatment was carried out by dipping the sensor element in a thiourea solution for 2 s, drying for 3 min, and heating at 600ЊC for 5 min. The concentration of the thiourea solution was varied within 0.020-0.80 mol dm Ϫ3 .The sensor element was placed in a stainless steel vessel (600 dm 3 ) which was equipped with a gas inlet and outlet and the terminals connected to the two coils of the sensor element inside. A pulsed voltage was applied between the two coils so as to switch the element temperature between 80 (90 s) and 280ЊC (60 s). This pulsed mode of operation is effective for enhancing the selectivity to CO vs. H 2 . 17,18 Fresh air controlled at 20ЊC and 65% relative humidity (RH) cont...

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Cited by 2 publications

References 0 publications

Structural and relaxor behavior of (Ba1−xLax)(Ti0.85Sn0.15)O3 ceramics obtained by solid state reaction

Structural and relaxor behavior of (Ba1−xLax)(Ti0.85Sn0.15)O3 ceramics obtained by solid state reaction

Effects of Thiourea Treatment on the Sensing Properties and Stability of SnO[sub 2]-Based CO Gas Sensors

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