Direct thermoelectric gas sensors: Design aspects and first gas sensors

Rettig, Frank; Moos, Ralf

doi:10.1016/j.snb.2006.09.002

Cited by 54 publications

(53 citation statements)

References 26 publications

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“…Details of such equipotential planes and the necessity for it for self-heated gas sensors with small sensor output signals have been shown previously in Ref. [31].…”

Section: Methodsmentioning

confidence: 99%

Selective mixed potential ammonia exhaust gas sensor

Schönauer

Wiesner

Fleischer

et al. 2009

Sensors and Actuators B: Chemical

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111

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“…Details of such equipotential planes and the necessity for it for self-heated gas sensors with small sensor output signals have been shown previously in Ref. [31].…”

Section: Methodsmentioning

confidence: 99%

Selective mixed potential ammonia exhaust gas sensor

Schönauer

Wiesner

Fleischer

et al. 2009

Sensors and Actuators B: Chemical

Self Cite

111

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“…It has to be corrected by the known Seebeck coefficient of platinum, S Pt . Details of the evaluation of S can be found in [49]

S = S_{P t} - \frac{U_{m e a s}}{Δ T}

…”

Section: Methodsmentioning

confidence: 99%

Influence of Oxygen Partial Pressure during Processing on the Thermoelectric Properties of Aerosol-Deposited CuFeO2

et al. 2016

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In the field of thermoelectric energy conversion, oxide materials show promising potential due to their good stability in oxidizing environments. Hence, the influence of oxygen partial pressure during synthesis on the thermoelectric properties of Cu-Delafossites at high temperatures was investigated in this study. For these purposes, CuFeO2 powders were synthetized using a conventional mixed-oxide technique. X-ray diffraction (XRD) studies were conducted to determine the crystal structures of the delafossites associated with the oxygen content during the synthesis. Out of these powders, films with a thickness of about 25 µm were prepared by the relatively new aerosol-deposition (AD) coating technique. It is based on a room temperature impact consolidation process (RTIC) to deposit dense solid films of ceramic materials on various substrates without using a high-temperature step during the coating process. On these dense CuFeO2 films deposited on alumina substrates with electrode structures, the Seebeck coefficient and the electrical conductivity were measured as a function of temperature and oxygen partial pressure. We compared the thermoelectric properties of both standard processed and aerosol deposited CuFeO2 up to 900 °C and investigated the influence of oxygen partial pressure on the electrical conductivity, on the Seebeck coefficient and on the high temperature stability of CuFeO2. These studies may not only help to improve the thermoelectric material in the high-temperature case, but may also serve as an initial basis to establish a defect chemical model.

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“…Possibly, an even improved model may help to develop to a system where the flow dependency can be neglected. This would be an important step forward for applications of thermoelectric sensors in transient conditions, for instance, in combustion engine exhausts as suggested by Rettig and Moos (2007) or Wu and Micheli (2004) and breath analysis (Nishibori et al, 2009;Shin et al, 2011) or wood combustion (Ojha et al, 2017).…”

Section: Discussionmentioning

confidence: 99%

“…Thermoelectric gas sensors are based on the principle that a temperature difference forms over thermopiles caused by exothermic reactions at a gas-sensitive area of the device (Park et al, 2014;Rettig and Moos, 2007). For example, the Cross section of the sensor device.…”

Section: Sensing Principlementioning

confidence: 99%

Simulation of a thermoelectric gas sensor that determines hydrocarbon concentrations in exhausts and the light-off temperature of catalyst materials

Ritter

Wiegärtner

Hagen

et al. 2017

J. Sens. Sens. Syst.

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Abstract. Catalyst materials can be characterized with a thermoelectric gas sensor. Screen-printed thermopiles measure the temperature difference between an inert part of the planar sensor and a part that is coated with the catalyst material to be analyzed. If the overall sensor temperature is modulated, the catalytic activity of the material can be varied. Exothermic reactions that occur at the catalyst layer cause a temperature increase that can then be measured as a sensor voltage due to the Seebeck coefficient of the thermopiles. This mechanism can also be employed at stationary conditions at constant sensor temperature to measure gas concentrations. Then, the sensor signal changes linearly with the analyte concentration. Many variables influence the sensing performance, for example, the offset voltage due to asymmetric inflow and the resulting inhomogeneous temperature distributions are an issue. For even better understanding of the whole sensing principle, it is simulated in this study by a 3-D finite element model. By coupling all influencing physical effects (fluid flow, gas diffusion, heat transfer, chemical reactions, and electrical properties) a model was set up that is able to mirror the sensor behavior precisely, as the comparison with experimental data shows. A challenging task was to mesh the geometry due to scaling problems regarding the resolution of the thin catalyst layer in the much larger gas tube. Therefore, a coupling of a 3-D and a 1-D geometry is shown. This enables to calculate the overall temperature distribution, fluid flow, and gas concentration distribution in the 3-D model, while a very accurate calculation of the chemical reactions is possible in a 1-D dimension. This work does not only give insight into the results at stationary conditions for varying feed gas concentrations and used substrate materials but shows also how various exhaust gas species behave under transient temperature modulation.

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Direct thermoelectric gas sensors: Design aspects and first gas sensors

Cited by 54 publications

References 26 publications

Selective mixed potential ammonia exhaust gas sensor

Selective mixed potential ammonia exhaust gas sensor

Influence of Oxygen Partial Pressure during Processing on the Thermoelectric Properties of Aerosol-Deposited CuFeO2

Simulation of a thermoelectric gas sensor that determines hydrocarbon concentrations in exhausts and the light-off temperature of catalyst materials

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