Effect of Electrode Microstructure on the Sensitivity and Response Time of Potentiometric NO<sub><i>X</i></sub> Sensors

White, Briggs M.; Chatterjee, Suman; Macam, Eric R.; Wachsman, Eric D.

doi:10.1111/j.1551-2916.2008.02384.x

Cited by 29 publications

(18 citation statements)

References 26 publications

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“…In other words, it will be the algebraic sum of the magnitude of the negative and positive voltages, thereby enabling an even higher CO sensitivity to be achieved. Furthermore, because adsorption−desorption are thermally activated processes, the response and recovery time of the sensors depend on temperature 4,9,42 . In addition, changes of the chemical (surface coverage, chemical reaction), physical (geometry, morphology), and electrical (charge‐carrier concentration, Fermi energy) properties of the semiconducting oxides are temperature dependent, and thus result in different voltage responses with diverse sensing mechanisms 22 .…”

Section: Introductionmentioning

confidence: 99%

Titania‐Based Miniature Potentiometric Carbon Monoxide Gas Sensors with High Sensitivity

Park

Azad

Song

et al. 2010

Journal of the American Ceramic Society

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Miniature, potentiometric, solid-state, carbon monoxide (CO) sensors with semiconducting oxide electrodes were investigated over the temperature range 5001-7001C. The effects of the electrochemical properties of the semiconducting oxides, after the addition of a catalyst and an alkaline metal oxide were evaluated in terms of the improvement in selectivity and response time. A sensor with high sensitivity and reversibility was obtained using a combination of an n-(titania) and p-type (composite titania with yttria and palladium) electrode to form a difference in the electrode equilibria. The device was able to measure a wide range of CO concentrations (10-16 000 ppm) with a high sensitivity to CO. A low-cost, rugged device could be fabricated because the sensing and reference electrodes were exposed to the same gaseous atmosphere. The results presented herein were attributed to the differential electrode equilibria mechanism, which comprises both semiconducting response and heterogeneous electrocatalysis contributions to the potentiometric sensor response.

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Section: Introductionmentioning

confidence: 99%

Titania‐Based Miniature Potentiometric Carbon Monoxide Gas Sensors with High Sensitivity

Park

Azad

Song

et al. 2010

Journal of the American Ceramic Society

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show abstract

“…When both electrodes are exposed to the CO gas, a voltage difference is generated between the two electrodes because the Fermi level of electrons of a semiconducting oxide electrode will be different from the average energy of electrons in the metal electrode. That is, the electrical (i.e., semiconducting) response is generated by the increased number of electrons generated by the formation of defects through adsorption–desorption reactions of these gas species at high temperatures 6–8,24–26 . Furthermore, the potential generated therein can identify the presence of a specific gas in gaseous mixtures, thus enhancing the cross sensitivity of the potentiometric sensor.…”

Section: Introductionmentioning

confidence: 99%

Highly Sensitive/Selective Miniature Potentiometric Carbon Monoxide Gas Sensors with Titania‐Based Sensing Elements

Park

Song

Wachsman

2010

Journal of the American Ceramic Society

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Miniature, potentiometric, solid‐state CO sensors utilizing titania‐based semiconducting oxide electrodes are studied at the operating temperature of the optimal response, i.e., 500°C. To improve the selectivity, sensitivity, and response time, yttria and palladium were mixed into the titania electrodes. Excellent sensing performance was obtained using an assembly of titania on one side and composite titania cermet synthesized by adding yttria and palladium on the other. The use of platinum contacts instead of gold current collectors afforded a substantial improvement in voltage response. The device detected an extended range of CO concentration (1–1000 ppm) with a high sensitivity to CO, while being capable of detecting even 1 ppm variations at low CO concentration ranges and retaining considerable selectivity to CO against CO2, NO, and O2 gases. Additionally, the response to CO is barely influenced by the coexisting interference gases (100 ppm NO, 16% CO2, 3% O2, 3% H2O).

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“…Recently, La 2 CuO 4 [332][333][334] and (La,Sr) 2 CuO 4 [335] have shown promise as electrodes for NO x sensors. The response of La 2 CuO 4 is attributed to the effect of the adsorbed intermediate N-O ionic species on the Fermi level in the electrode.…”

Section: Electrocatalytic Electrodesmentioning

confidence: 99%

Electrochemical Sensors: Fundamentals, Key Materials, and Applications

Fergus

2009

Solid State Electrochemistry I

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Solid electrolytes are well suited for use in chemical sensors for high-temperature applications. The first such sensors followed from the use of solid electrolytes for thermodynamic measurements, and are based on galvanic cells, for which the open circuit voltage is related to the concentration of the mobile ionic species, or to another target species through equilibration at the electrode surface. However, sensors can also be based on nonequilibrium, but steady-state, potentials established between electrochemical reactions at the electrode. Another approach is to use the current passing through the electrolyte, rather than the voltage across the electrolyte, as the sensor signal. In this chapter we first describe the different methods for using solid electrolytes in chemical sensors, and then discuss some of the materials challenges and example applications. IntroductionMore than 50 years ago, Kiukkola and Wagner [1] demonstrated that solid electrolytes couldbeusedingalvaniccellstomeasurethethermodynamicpropertiesofoxides.Those pioneering studies subsequently led to the more practical application of solid electrolytes in chemical sensors. The ionic conduction in solid electrolytes is thermally activated and thus its rate increases with increasing temperature; consequently, solid electrolytes are well suited for high-temperature applications. On the other hand, such temperature dependencealsomeansthatsensorsbasedonsolidelectrolytescanrespondsluggishlyor may be inoperable at low temperatures. However, one of the advantages of solid-state devices, such as those based on solid electrolytes, is that they can be miniaturized [2,3]. Decreasingthedevicedimensionsreducesdiffusionlengths,whichinturndecreasesthe response time and thus also the minimum operating temperature.Ionic conducting solids can be used in a variety of different types of sensor [4][5][6][7][8][9][10][11][12]. Solids forwhichthe ionicconductivity is much largerthanthe electronic conductivity can Solid State Electrochemistry I: Fundamentals, Materials and their Applications. Edited by Vladislav V. Kharton

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Effect of Electrode Microstructure on the Sensitivity and Response Time of Potentiometric NO_X Sensors

Cited by 29 publications

References 26 publications

Titania‐Based Miniature Potentiometric Carbon Monoxide Gas Sensors with High Sensitivity

Titania‐Based Miniature Potentiometric Carbon Monoxide Gas Sensors with High Sensitivity

Highly Sensitive/Selective Miniature Potentiometric Carbon Monoxide Gas Sensors with Titania‐Based Sensing Elements

Electrochemical Sensors: Fundamentals, Key Materials, and Applications

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Effect of Electrode Microstructure on the Sensitivity and Response Time of Potentiometric NOX Sensors

Cited by 29 publications

References 26 publications

Titania‐Based Miniature Potentiometric Carbon Monoxide Gas Sensors with High Sensitivity

Titania‐Based Miniature Potentiometric Carbon Monoxide Gas Sensors with High Sensitivity

Highly Sensitive/Selective Miniature Potentiometric Carbon Monoxide Gas Sensors with Titania‐Based Sensing Elements

Electrochemical Sensors: Fundamentals, Key Materials, and Applications

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Product

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Effect of Electrode Microstructure on the Sensitivity and Response Time of Potentiometric NO_X Sensors