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Potentiometric NO2 Sensors Based on Thin Stabilized Zirconia Electrolytes and Asymmetric (La0.8Sr0.2)0.95MnO3 Electrodes.

Zou J, Zheng Y, Li J, Zhan Z, Jian J - Sensors (Basel) (2015)

Bottom Line: Measurements of their sensing characteristics show that reducing the porosity of the supporting LSM95 reference electrodes can increase the response voltages.The best linear coefficient can be as high as 0.99 with a sensitivity value of 52 mV/decade as obtained at 500 °C.Analysis of the sensing mechanism suggests that the gas phase reactions within the porous LSM95 layers are critically important in determining the response voltages.

View Article: PubMed Central - PubMed

Affiliation: Gas Sensors & Sensing Technology Laboratory, College of Information Science and Engineering, Ningbo University, Ningbo 315211, China. ljl2005@mail.sic.ac.cn.

ABSTRACT
Here we report on a new architecture for potentiometric NO2 sensors that features thin 8YSZ electrolytes sandwiched between two porous (La0.8Sr0.2)0.95MnO3 (LSM95) layers-one thick and the other thin-fabricated by the tape casting and co-firing techniques. Measurements of their sensing characteristics show that reducing the porosity of the supporting LSM95 reference electrodes can increase the response voltages. In the meanwhile, thin LSM95 layers perform better than Pt as the sensing electrode since the former can provide higher response voltages and better linear relationship between the sensitivities and the NO2 concentrations over 40-1000 ppm. The best linear coefficient can be as high as 0.99 with a sensitivity value of 52 mV/decade as obtained at 500 °C. Analysis of the sensing mechanism suggests that the gas phase reactions within the porous LSM95 layers are critically important in determining the response voltages.

No MeSH data available.


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SEM micrographs of sensors, (a) Low magnification view of fractured S-LSM95; (b) High magnification view of S-LSM95; and (c) High magnification view of S-Pt.
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sensors-15-17558-f008: SEM micrographs of sensors, (a) Low magnification view of fractured S-LSM95; (b) High magnification view of S-LSM95; and (c) High magnification view of S-Pt.

Mentions: Figure 8a shows a representative cross-sectional SEM micrograph of the new S-15LSM95 sensors with thin LSM95 layers as SEs, where the thick LSM95 layers as REs are ≈580 μm thick. By the way, all sensors have similar thickness of REs. Higher-magnification view (Figure 8b) shows that both LSM95 layers display similar porous microstructures with high enough porosity to facilitate the gas transport. Note that the 8YSZ electrolytes are fully dense after firing at 1225 °C, which is 100–200 °C lower than the commonly required sintering temperature. Such observations can be explained by the large shrinkage (>23%) of the thick LSM95 layers at lower sintering temperatures, which is conducive to the densification of thin YSZ electrolytes [23]. Figure 8b also shows that the thickness is 14 μm for thin LSM95 layers and 23 μm for YSZ electrolytes. For the NO2 sensors S-Pt with thin Pt layers as SEs, the microstructure of the supporting LSM95 substrates (Figure 8c) are largely the same as observed for S-LSM95. The Pt layers are ≈5 μm thick and contained relatively large pores due to the excessive sintering during the co-firing process.


Potentiometric NO2 Sensors Based on Thin Stabilized Zirconia Electrolytes and Asymmetric (La0.8Sr0.2)0.95MnO3 Electrodes.

Zou J, Zheng Y, Li J, Zhan Z, Jian J - Sensors (Basel) (2015)

SEM micrographs of sensors, (a) Low magnification view of fractured S-LSM95; (b) High magnification view of S-LSM95; and (c) High magnification view of S-Pt.
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Related In: Results  -  Collection

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sensors-15-17558-f008: SEM micrographs of sensors, (a) Low magnification view of fractured S-LSM95; (b) High magnification view of S-LSM95; and (c) High magnification view of S-Pt.
Mentions: Figure 8a shows a representative cross-sectional SEM micrograph of the new S-15LSM95 sensors with thin LSM95 layers as SEs, where the thick LSM95 layers as REs are ≈580 μm thick. By the way, all sensors have similar thickness of REs. Higher-magnification view (Figure 8b) shows that both LSM95 layers display similar porous microstructures with high enough porosity to facilitate the gas transport. Note that the 8YSZ electrolytes are fully dense after firing at 1225 °C, which is 100–200 °C lower than the commonly required sintering temperature. Such observations can be explained by the large shrinkage (>23%) of the thick LSM95 layers at lower sintering temperatures, which is conducive to the densification of thin YSZ electrolytes [23]. Figure 8b also shows that the thickness is 14 μm for thin LSM95 layers and 23 μm for YSZ electrolytes. For the NO2 sensors S-Pt with thin Pt layers as SEs, the microstructure of the supporting LSM95 substrates (Figure 8c) are largely the same as observed for S-LSM95. The Pt layers are ≈5 μm thick and contained relatively large pores due to the excessive sintering during the co-firing process.

Bottom Line: Measurements of their sensing characteristics show that reducing the porosity of the supporting LSM95 reference electrodes can increase the response voltages.The best linear coefficient can be as high as 0.99 with a sensitivity value of 52 mV/decade as obtained at 500 °C.Analysis of the sensing mechanism suggests that the gas phase reactions within the porous LSM95 layers are critically important in determining the response voltages.

View Article: PubMed Central - PubMed

Affiliation: Gas Sensors & Sensing Technology Laboratory, College of Information Science and Engineering, Ningbo University, Ningbo 315211, China. ljl2005@mail.sic.ac.cn.

ABSTRACT
Here we report on a new architecture for potentiometric NO2 sensors that features thin 8YSZ electrolytes sandwiched between two porous (La0.8Sr0.2)0.95MnO3 (LSM95) layers-one thick and the other thin-fabricated by the tape casting and co-firing techniques. Measurements of their sensing characteristics show that reducing the porosity of the supporting LSM95 reference electrodes can increase the response voltages. In the meanwhile, thin LSM95 layers perform better than Pt as the sensing electrode since the former can provide higher response voltages and better linear relationship between the sensitivities and the NO2 concentrations over 40-1000 ppm. The best linear coefficient can be as high as 0.99 with a sensitivity value of 52 mV/decade as obtained at 500 °C. Analysis of the sensing mechanism suggests that the gas phase reactions within the porous LSM95 layers are critically important in determining the response voltages.

No MeSH data available.


Related in: MedlinePlus