Perovskite-type oxides sensors

Oxygen Sensor Using Perovskite-Type Oxides... 

Grilli, M.L., Di Bartolomeo, E. and Traversa, E. (2001) Electrochemical NOx sensors based on interfacing nanosized LaFeOj perovskite-type oxide and ionic conductors. J. Electrochem. Soc., 148 (9), H98-102. 

Shimizu Y etal 1989 The sensing mechanism in a semiconducting humidity sensor with platinum electrodes J. Electrochem. Soc. 136 3868-71 Lukaszewicz J P 1991 Diode-type humidity sensor using perovskite-type oxides operable at room temperature Sensors Actuators B 4 227-32 Anderson RC etal 1990 Investigations of porous silicon for vapor sensing Sensors Actuators A 23 835-9... 

When water molecules are adsorbed on semiconducting oxides, the conductivity increases or decreases according to whether the oxides are n- or p-type. In response to demands for operation at elevated temperatures, semiconductor humidity sensors using metal oxides, such as perovskite-type oxide, have been proposed as shown in Table 20-2. 

Yu C., Shimizu Y., and Arai H., Investigations on a lean-bum sensor using perovskite type oxides, Chem. Lett., 14, 563-566, 1986. 

Kida,T.,Kishi,S.,Yuasa,M.,Shimanoe,K. and Yamazoe,N. (2008),Planar NASICON-based COj sensor using BiCuVOx/Perovskite-type oxide as a solid-reference electrode, Journal of the Electrochemical Society, 155, J117-21. 

Santhosh P, Manesh KM, Gopalan A, Lee K-P (2007) Novel amperometric carbon monoxide sensor based on multi-wedl carbon nanotubes grafted with polydiphenylamine-fabrication and performance. Sens Actuators B 125 92-99 Shai K, Wagner J (1982) Enhanced ionic conduction in dispersed solid electrolyte systems (DSES) and/or multiphase systems Agl-Al Oj, Agl-SiO, Agl-Ely ash, and Agl-AgBr. J Sohd State Chem 42 107-119 Shimizu Y, Yamashita N (2000) Solid electrolyte CO sensor using NASICON and perovskite-type oxide electrode. Sens Actuators B 64 102-106... 

Inoue T, Seki N, Eguchi K, Arai H (1990) Low-temperature operation of solid electrolyte oxygtai sensors using perovskite-type oxide electrodes and cathodic reaction kinetics. J Electrochem Soc 137(8) 2523-2527... 

One type of humidity sensor utilizes porous perovskite-type ceramic materials. Perovskite-type metal oxides are good candidates because their surfaces can be easily modified in order to obtain water adsorptive properties by choosing an appropriate cation in the oxides. In addition, the perovskite-type oxides do not require thermal treatment. Also, no influence is expected in sample gases from coexisting CO2. As the metals in perovskite... 

Humidity sensors which use ionic oxides operate at around room temperature. The output of such a humidity sensor changes gradually with time. However, humidity sensors of the semiconductor type work well at elevated temperatures and maintain a stable output although there is interference from reducing gas, particularly ethanol. When the water vapor content increases, interference from reducing gases becomes smaller. The rare earth lanthanum also plays an important role in the perovskite-type humidity sensor. The rare earth enhances the interaction between the adsorbed species and the oxides at the surface (Shimizu et al. 1985). 

A protonic conductor such as CaZro 9lno.i Os- , can be applied to sense hydrocarbon gases. In this case, two different electrodes were used. One is silver metal which is a material inert to hydrocarbons and the other is a perovskite-type oxide (Lao.6Bao.4Co03) which contains rare earth and accelerates the combustion of hydrocarbons. The chemical reaction occurring in the sensor is shown in fig. 69 (Hibino and Iwahara 1994). Hydrocarbons in the ambient atmosphere do not react on the Ag electrode. On the contrary, hydrocarbons react with oxygen and form water vapor and carbon dioxide on the oxide electrode surface. 

Aral, H., S. Ezaki, Y. Shimizu, 0. Shippo and T. Seiyama, 1983, Semiconductive humidity sensor of perovskite-type oxides, in Proc. Int. Meeting on Chemical Sensors, eds T. Seiyama, K. Fueki, J. Shoikawa and S. Suzuki (Kodansha/Elsevier) pp. 393-398. 

The more researches on lanthanum-containg composite oxides are the perovskite-type oxides. They possess a imique crystal structure, especially the crystal defect. They are widely used in various fields, such as solid oxide fuel cells, solid electrolytes, sensors, solid resistors, and especially are used as redox catalysts to replace precious metals, which has an extensive prospect in heterogeneous catalysis. 

Materials with high proton or oxide ion conductivity are widely studied for their potential application as electrolytes in fuel cells, electrolysers, batteries, sensors, ete. [1-5], Acceptor doped perovskite-type oxides ABO3.5 where A is Sr, Ba and B is Ce, Zr are well-known high temperature proton conductors in wet atmosphere. It was found that the main factor responsible for the appearance of protons in the structure was the presence of oxygen vacancies. Upon hydration by equilibration with water vapor the oxygen vacancies may be filled by oxygen from water and, in accordance with dissociative mechanism of water dissolution, the hydroxide ions are formed. In this case the dissolution of water may be written [6] ... 

Thin films, to attain enough sensitivity and response time, of oxide materials normally deposited on a substrate are typically used as gas sensors, owing to their surface conductivity variation following surface chemisorption [183,184], Surface adsorption on a Sn02 film deposited on alumina produces a sensitive and selective H2S gas sensor [185]. In addition, a number of perovskite-type compounds are being used as gas sensor materials because of their thermal and chemical stabilities. BaTi03, for example, is used as sensor for C02 [183],... 

The pyroelectric response of ferroelectrics may be exploited to detect tem-peratnre changes with extremely high sensitivity. The most common devices are nncooled infrared (IR) detectors, which may be used for spectroscopic analysis as well as imaging apphcations. Pyroelectric thin films based on perovskite-type complex oxides, including Pb(Sc,Ta)03 have been deposited by CSD for intruder alarms, gas sensors, and IR cameras. It is anticipated that these thin-film devices will be substantially less expensive to manufacture than existing bulk polycrystaUine devices, which require labor-intensive manufacturing procedures. 

Ishihara T (ed) (2009) Perovskite oxide for solid oxide fuel cells. Springer, Dordrecht Ishihara T, Matsubara S (1998) Capacitive type gas sensors. J Electroceram 2(4) 215-228... 

Wagner T, Hennemann J, Kohl C-D, Tiemann N (2011) Photocatalytic ozone sensor based on mesoporous indium oxide influence of the relative humidity on the sensing performance. Thin Sohd Films 520 918-921 Wakamura K (2005) Empirical relationships for ion conduction based on vibration amplitude in perovskite-type proton and superionic conductors. J Phys Chem Solids 66 133-142 Wang W, Virkar AV (2005) Ionic and electron-hole conduction in BaZr, Y j,03 d by 4-probe DC measurements. J Power Sources 142(1-2) 1-9... 

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