Sensing Characteristics of YSZ-Based Mixed-Potential-Type Planar NO[sub x] Sensors Using NiO Sensing Electrodes Sintered at Different Temperatures

Abstract

The correlation between the sintering temperature and the NO 2 sensing performances of the planar mixed-potential-type yttriastabilized zirconia ͑YSZ͒-based NO x sensor attached with NiO sensing electrode ͑SE͒ was studied by materials characterization techniques, such as impedance analysis, polarization analysis, scanning electron microscopy, and transmission electron microscopy. The sensing properties of the planar YSZ-based NO x sensors were investigated in the operating temperature range of 700-900°C. The NO 2 sensitivity of the present sensor was found to be modulated by changing the sintering temperature of NiO-SE. Rather large sensitivity ͑43 mV͒ to 100 ppm NO 2 was obtained even at 800°C for the sensor using the NiO-SE sintered at 1400°C. A sensing mechanism that involves mixed potential at SE as well as catalysis in gas-phase reaction was discussed based on the results obtained.

A Stable Sensing-Electrode Material in Reducing Atmosphere at High Temperature for Zirconia-Based Amperometric NOx Sensor

“…Precursor solutions were made from La(NO 3 sonically misted and introduced to a tubular furnace kept at 800°C under a flowing air. The obtained powder was subsequently calcined at 1200°C for 2 h in air.…”

The NO₂ Response of Solid Electrolyte Sensors Made Using ZnFe₂O₄ Electrodes

“…During the diffusion in the ZnFe 2 O 4 layer, reaction (3) occurs. 8) As grains became larger, NO 2 gas makes fewer contacts with the surface of the ZnFe 2 O 4 grains during operations when it diffuses through the pores, where surface of the grains act as a catalyst for the gas-phase reaction (3). Thus, NO 2 can reach the YSZ/SE interface without serious decomposition to NO.…”

“…6) Many researches put a lot on ZnFe 2 O 4 electrodes which are nanometer and small micrometer size at present. 7,8) For example, in Serge Zhuiykov's research, the size of ZnFe 2 O 4 particle is smaller than 1 µm. And the values of EMF are 42 and 28 mVat 650 and 700°C respectively.…”

Hierarchical Nanoceramics for Industrial Process Sensors

“…The mixed-potential results in a deviation from the Nernst predicted EMF. Gas phase reactions over catalytic electrodes have also been considered to influence sensor EMF [Fleming 1977, Hibino 1999, Elumalai 2005, Elumalai 2009]. In addition, the semiconducting nature associated with the adsorption and desorption of gas species on select metal-oxide electrodes can alter the EMF [Wachsman 2001, Di Bartolomeo JAmCeramSoc 2004, Di Bartolomeo JElectroChemSoc 2004.…”