Papers by Keyword: NOx Sensor

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Authors: Youichi Shimizu, Satoko Takase, Daisuke Koba
Abstract: A new solid-electrolyte impedance-metric NOx sensor device composed of a lithium ionic solid electrolyte: Li1.5Al0.5Ti1.5(PO4)3 (LATP) as a transducer and ceramic oxides (perovskite-type oxides, TiO2, SnO2, etc) as a receptor, respectively, have been systematically investigated for the detection of NOx (NO and NO2 ) in the range 10 – 200 ppm at 400 - 500°C. Responses of the sensors were able to divide component between resistance and capacitance, and it was found that the device was applicable to the selective detection of NO or NO2 concentration in each ingredient. Especially, those using TiO2, SnO2 (n-type semiconductor) and perovskite-type oxides (LaCoO3, LaNiO3 and LaCrO3) based receptors gave good responses to NO and NO2. It was also found that the responses were different between n-type or p-type semiconductors, in which we tried to elucidate the sensing mechanism
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Authors: Chang Tian Huan, Dan Yu Jiang, Ge Ming Liu, Qiang Li
Abstract: There are many bonding methods of the ceramic sintered body, such as diffusion bonding, glass bonding, and reports in this regard are not difficult to see. But the solid electrolyte zirconia ceramic bonding in NOx sensor is rarely reported. Here we use zirconia and aluminum-silicon glass together to bond zirconia ceramic sintered body, and tested the electrochemical performance with AC (alternating current) impedance spectroscopy, EMF (electromotive force) of the adhesive layer. The results indicates that the the electrochemical performance is good.
376
Authors: Piotr Kurek, S. Thiemann-Handler, M. Marzantowicz, M. Wasiucionek
Abstract: Growing awareness of dangers related to NOX emission by industry and road transportation has resulted in increasing demand for sensors detecting NOX. An important class of these sensors use Pt-based electrodes applied on yttria-stabilized zirconia (YSZ) substrates. Performance of such sensors depends on redox reactions occurring at electrodes in the tested atmospheres. Impedance spectra and j-U curves of PtRh electrodes were measured in a 3-electrode mode, using Pt metal pads as counter and reference electrodes. The data were collected in a 10mHz- 100kHz frequency range at temperatures from 450 to 750°C. Each series of measurements was carried out in a gas mixture with different oxygen content ranging from 0 to 21 vol%. It was found out that the low-frequency part of the impedance spectra (characterizing electrode processes) was sensitive to the oxygen content in the gas mixtures.
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Authors: Hai Qin Huang, Guang Yuan Xie, Yun Ming Gao, Ying Jun Pan
Abstract: A thick film ZrO2-based NOx sensor feasible for diesel and gasoline engine applications has three diffusion paths, the size of paths has a great influence on sensor signal output. This paper studies the relationship between the pump current signal and the size of paths, the manufacture of NOx sensors of varied path sizes by the method of filling organics and then sintering at a high temperature to form a stable path, and detections of the sensors in a standard gas chamber. Then matching sizes of three paths are obtained.
2181
Authors: Tao Feng, Jin Feng Xia, Hong Qiang Nian, De Xin Huang, Hai Fang Xu, Yu Lin Li, Bing Xu, Dang Yu Jiang
Abstract: Mixed-potential-type NO2 sensor based on yttria-stabilized zirconia(YSZ) with NiO sensing electrode was prepared by the screen-printing technique and its physical characteristics were studied by the X-ray diffraction and scanning electron microscope. The response of electromotive force (EMF) and complex impedance of the sensor were tested under different NO2 concentrations and temperatures. The results show that, at the range of 550–750 °C, the EMF values are negative and almost linear to the logarithm of NO2 concentration. But the sensitivity of the sensor and the amplitude of the EMF response to NO2 concentration both obviously decrease with the increase of the work temperature. In addition, the semicircular arcs of the complex impedance spectra shrink regularly with a raise of NO2 concentration at 600 °C.
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Authors: Yin Lin Wu, Hai Yan Zhao, Ling Wang
Abstract: Electrochemical sensors based on tubular yttria-stabilized zerconia (YSZ) with the perovskite-type oxide as a sensing-electrode (SE), which is prepared by sol-gel method, were fabricated and examined for NO2 detection in the temperature range 400~700°C. The results show that La0.75Sr0.25Cr0.5Mn0.5O3(LSCM), shows extreme sensitivity to NO2. The EMF varies linearly as a function of the concentration of NO2 (0 ~ 463 ppm) at 500 °C.
109
Authors: Yin Lin Wu, Hai Yan Zhao, Qing Hui Wang, Ling Wang
Abstract: Electrochemical sensors based on tubular yttria-stabilized zerconia (YSZ) with the spinel-type oxide as a sensing-electrode (SE), which is prepared by sol-gel method, were fabricated and examined for NO2 detection in the temperature range 450~500°C. The results show that ZnFe2O4, shows extreme sensitivity to NO2. The EMF varies linearly as a function of the concentration of NO2 (0 ~ 463 ppm) at 500 °C.
253
Authors: Li Hong Zhou, Hai Yan Wu, Quan Yuan, Xiang Dong Li, Pei Wei Xu, Rong Wang, Feng Xia, Jian Zhong Xiao
Abstract: The powder of (La0.8Sr0.2)2FeNiO6-δ (LSFN) oxide with double-perovskite structure was synthesized by polymeric precursor method. Then the YSZ-based NO sensors with LSFN sintered at different temperatures (1000, 1100, 1200 and 1300 °C) as sensitive electrode (SE) were fabricated. All samples were characterized by XRD. The morphologies of the LSFN-SEs were observed with ESEM. The NO sensing properties of the sensors were investigated in the operating temperature range of 350-650 °C in 10 vol. % O2. Results demonstrated that the sensor with LSFN-SE sintered at 1300 °C exhibited highest response to 500 ppm NO at 400 °C, which was about 85 mV. A linear relationship was obtained between the emf and the logarithm of NO concentration from 500 to 800 ppm at 400 and 500 °C. Moreover, both magnitude and slope to NO response decreased as operating temperature increased. And both the response time and recovery time shortened as temperature increased. But the recovery rate was slower than the response rate, especially at and below 450 °C. The optimal sensor response was obtained at 500-550 °C.
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