NASICON sensor

Min, B.-K. and Choi, S.-D. (1995) SO2-sensing characteristics of Nasicon sensors with Na2SO4-BaSO4 auxiliary electrolytes. Sens. Actuators B, 95,209-15. 

Min B-K, Choi S-D (2003) SO -sensing characteristics of Nasicon sensors with Na SO -BaSO auxiliary electrolytes. Sens Actuators B 93 209-213... 

A similar device with Nasicon solid electrolyte Na3Sc(P04)3 is used when analyzing the concentration of nitrogen oxides in air. The electrochemical system in this sensor can be formnlated as... 

This is achieved in the electrochemical C02 sensor to be described now. The gas sensitive electrode in the emf sensors for C02 detection is based on an alkaline or alkaline earth carbonate.41"43 If Na2C03 is to be used, Na- (5" -alumina or Nasicon (Part I2) are suitable electrolytes. A thermodynamically well-defined sensor is obtained by using a mixture of a binary and a ternary oxide such as42 Na2C03, C02 Na+ -conductorj Na2M03, M02... 

Instead of the system silica/silicate also other systems such as titania/titanate, zirconia/zirconate can be used as a reference system [xiv]. The response time of freshly fabricated thick-film sensors based on thin-film /3-alumina is very short (about 15 ms at 650 °C). After several weeks of operating this time increases 10 times (150 ms) [xv]. Solid electrolyte C02 sensors using Ni/carbonate composite as measuring electrode are suited for measuring of C02 in equilibrated water gases [xiv]. Using semiconducting oxides and carbonates like ITO (indium tin oxide) Nasicon-based C02 sensors are able to measure at room temperature [xvi]. 

Damascene, O., Siebert, E., Khireddine, H., and Fabry, R, Ionic exchange and selectivity of NASICON sensitive membranes. Sensors Actuators B, 8, 245-248 (1992). 

Figure 13.7 Outputs of CO2 and SO2 sensors with NASICON/p alumina electrolyte chains [88-91],...

An additional electrolyte can also provide the auxiliary electrode function. For example, Na2CO3 can be used with NaP alumina [135-137], NASICON [138-146], or a sodium aluminosilicate glass [147] as the electrolyte for a CO2 sensor, in which case the Na2CO3 equilibrates with CO2 in the gas and Na in the electrolyte according to the following reaction ... 

Figure 13.10 Outputs of CO2 sensors based on NASICON or carbonate electrolytes at 400-405 °C [81, 148, 150, 151, 162].

In a similar way, Na2SO4 has been used as an auxiliary electrode with sodium ion conductors (Na P alumina [179] or NASICON [180]). As with carbonates for CO2 sensors, mixed sulfates (e.g., Na2SO4-BaSO4 [181]) can be used for the auxiliary electrode. At low oxygen partial pressures, sulfur maybe present as H2S, rather than as SOx, in which case sulfides can be used as auxiliary electrodes. For example, CaS has been used with a CaF2 electrolyte for measuring H2S gas concentrations [182]. 

Figure 13.13 Sensitivities of CO2 sensors based on NASICON electrolytes and mixed carbonate auxiliary electrodes [151, 160, 176],... 

The carbonate phase can also form from reaction between the cation in the electrolyte and CO2 from the atmosphere, in which case a carbonate phase need not be added. For example, a CO2 sensor with a NASICON electrolyte and an indium tin oxide (ITO) electrode relies on the in situ formation of Na2CO3 during sensor operation [205], Similarly, the formation of Li2CO3 allows LiLaGeO4 to be used as the electrolyte for a CO2 sensor [206]. 

The outputs of some mixed potential-type chemical sensors correlate with the type of electronic defect (i.e., n-type versus p-type), so the response has been attributed to the semiconducting behavior of the electrode material [314]. LaFeO3, which has been used as a semiconductor-type gas sensor ] 315, 316], has also been used as an electrode with YSZ [255, 263, 317] or NASICON ]317, 318] electrolytes for potentiometric NO, sensors. Strontium (i.e., (La,Sr)FeO3 ]255, 256, 284]) or strontium and cobalt (i.e., (La, Sr)(Co,Fe)O3 ]275, 280, 309]) have been added to LaFeO3 to improve electrode performance. (La,Ca)MnO3 doped with either cobalt or nickel on the manganese site has been used as the electrode for N O, sensors ]319]. The outputs of some NO, sensors with perovskite electrodes are shown in Figure 13.26 ]255, 256, 264, 275, 309, 312]. 

Wang, L. and Kumar, R.V. (2005) A SO2 gas sensor based upon composite Nasicon/Sr-p-AhOj bielectrolyte. Mater. Res. Bull., 40, 1802-15. 

K. and Yamazoe, N. (2008) Planar NASICON-based CO2 sensor using BiCuVOx/perovsldte-type oxide as a solid-reference electrode./. Electrochem. Soc., 155 (5), J117-21. 

Obata, K., Kumazawa, S., Shimanoe, K., Miura, N. and Yamazoe, N. (2001) Potentiometric sensor based on NASICON and In2O3 for detection of CO2 at room temperature - modification with foreign substances. Sens. Actuators B. 76, 639-43. 

Pasierb, P., Komornicki, S., Kozinski. S., Gajerski, R. and Rckas, M. (2004) Longterm stability of potentiometric CO2 sensors based on Nasicon as a solid... 

Zhu, Q., Qiu. F., Quan, Y., Sun, Y.. Liu. S. and Zou, Z. (2005) Solid-electrolyte NASICON thick film CO2 sensor prepared on small-volume ceramic tube substrate. Mater. Chem. Phys., 91 (2-3), 338-42. 

Sadaoka, Y. (2007) NASICON based CO2 gas sensor with an auxiliary electrode composed of LiCOj-metal oxide mixtures. Sens. Actuators B, 121. 194—9. 

Chen, S., Jeng, D.-Y., Hadano, H., Ishiguro, Y., Nakayama, M. and Watanabe, K. (2005) A Nasicon CO2 gas sensor with drift-detection electrode. IEEE Trans. Instrumentation and Measurement, 52 (5). 1494-500. 

Miyachi, Y., Sakai, G., Shimanoe, K. and Yamazoe, N. (2004) Stabilization of counter electrode for NASICON based potentiometric CO2 sensor. Ceram. Eng. Sci. Proc., 25 (5). 471-6. 

Bhoga. S.S. and Singh. K. (2005) Performance of electr ochemical CO2 gas sensor with NASICON dispersed in a binar y solid electrolyte system. Indian J. Phys.. 79 (7). 725-6. 

Yao, S., Hosohara, S.. Shimizu. Y. Miura. N., Futata, H. and Yamazoe, N. (1991) Solid electrolyte CO2 sensor using NASICON and Li-based binary carbonate electrode. Chem. l tt., 2069—72. 

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