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Author Tuttle, Bruce ♦ Clive, R. ♦ Viehl, Dwight ♦ Miura, N. ♦ Wang, J. ♦ Nakatou, M. ♦ Elumalai, P. ♦ Zhuiykov, S. ♦ Terada, D. ♦ Ono, T.
Source CiteSeerX
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Subject Domain (in DDC) Computer science, information & general works ♦ Data processing & computer science
Subject Keyword Co Vriahto2005 ♦ Yttria-stabilized Zirconia ♦ Oxygen Concentration ♦ High Temperature ♦ Impedancemetric Sensor ♦ Nox Sensor ♦ Nonelectrochemical Reaction ♦ High Sensitivity ♦ Impedancemeteric Nox Sensor ♦ High Temperature Range ♦ Low-cost Solid-state Sensor ♦ Co-existing Combustible Gas ♦ Nox Sensitivity ♦ Annual Average ♦ Air Quality Regulation ♦ Dry Sample Gas ♦ Concentration Range ♦ Solid-state Electrochemical Sensor ♦ Different Application ♦ Various Single-oxide S ♦ Hourly Maximum ♦ Water Vapor ♦ Nox Detection ♦ Catalytic Activity ♦ Linear Dependence ♦ Exhaust Gas ♦ Nitrogen Oxide ♦ Zncrzodje Exhibit Good Sensing Characteristic ♦ Mixed-potential-type Nox Sensor ♦ Oxide Sensing Electrode ♦ Strong Recent Legislation ♦ Planar Laminated-type Structure ♦ Recovery Transient
Abstract Solid-state electrochemical sensors using yttria-stabilized zirconia (YSZ) and oxide sensing electrode (SE) were fabricated and examined for NOx detection at high temperatures. Among various single-oxide SEs examined, NiQSE for the mixed-potential-type NOx sensor was found to exhibit rather high sensitivity to N @ even in the high temperature range of 800-900°C. This sensor showed quicker response and recovery transients in the presence of water vapor, compared with that in the dry sample gas. The sensing mechanism of this type of sensor was discussed on the basis of the catalytic activities to the electrochemical and nonelectrochemical reactions. It was also shown that the new-type complex-impedance-based (impedancemetric) NOx sensor attached with ZnCrzOdjE exhibit good sensing characteristics to NOx at 70OOC. Furthermore. the sensitivity to NO was almost equal to that to NO2 in the concentration range from 0 to ca. 200 ppm at 700°C. A linear dependence was observed between the sensitivity of the impedancemetric sensor and the concentration of NOx even in the presence of 8 vol. % H20 and 15 vol. % C02. The planar laminated-type structure for the impedancemeteric NOx sensor was proposed for protecting NOx sensitivity from the influences of the co-existing combustible gases as well as the change in oxygen concentration in exhaust gas. lNTRODUCTION Recently, the demand for reliable, compact, low-cost solid-state sensors, which are capable of detecting nitrogen oxides (NOx) in different application, has been enhanced substantially. This demand has been driven by strong recent legislation in EU, USA and Japan. For example, in UK under Air Quality Regulations (1997) for NOx, standards of 150 ppb (hourly maximum) and 21 ppb (annual average) must be achieved by the end of 2005. ' On the
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