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Author |
Lenaerts, S.; Honoré, M.; Huyberechts, G.; Roggen, J.; Maes, G. |
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Title |
In situ infrared and electrical characterization of tin dioxide gas sensors in nitrogen/oxygen mixtures at temperatures up to 720 K |
Type |
A1 Journal article |
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Year |
1994 |
Publication |
Sensors and actuators : B : chemical |
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Volume |
19 |
Issue |
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Pages |
478-482 |
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Keywords |
A1 Journal article |
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Abstract |
FT-IR spectroscopy and impedance measurements of tin dioxide sensor materials at working temperatures up to 450 °C in atmospheres with varying O2/N2 ratio are used as an in situ probe to study the interactions at the surface of the semiconducting oxide. Every diminution in the oxygen content above the sample induces a broad IR absorption band (X-band) between 2300700 cm−1 with a few small peaks in the 1400850 cm−1 region of the spectrum superimposed on it. The X-band results from the enchanced electron concentration in the bulk of the tin dioxide domain. The fine structure is due to the absorption of several kinds of surface oxygen species associated vibration modes. The porous tin dioxide consists of domains were the outward shell is depleted of electrons by the formation of adsorbed O− species on oxygen surface sites, SO(O− species. In our proposed model for the impedance data this gives rise to a parallel RpCp circuit for the domain boundary characteristics and to an Rs parameter for the intradomain resistance. The evolution of these IR and impedance spectroscopic effects with temperature and oxygen content is used to set up, to confirm and refine a physicochemical operation model of tin dioxide gas sensor. This model consists of a sensitizing reaction sequence in the presence of oxygen and a gas-detection reaction sequence when a reducing gas is present. Based on this model, the principal disadvantages of this type of gas sensor become clear. Every factor that influences the concentration of SO(O−) species, causes a conductance modification. If we can control and direct the nature, the number and the arrangement of the tin dioxide domains, a directed development and improvement of the sensor characteristics is possible. |
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A1994NN90000040 |
Publication Date |
2002-07-25 |
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ISSN |
0925-4005 |
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UA library record; WoS full record; WoS citing articles |
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no |
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Call Number |
UA @ admin @ c:irua:82014 |
Serial |
5962 |
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Author |
Lenaerts, S.; Roggen, J.; Maes, G. |
![find record details (via OpenURL) openurl](img/xref.gif)
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Title |
FT-IR characterization of tin dioxide gas sensor materials under working conditions |
Type |
A1 Journal article |
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Year |
1995 |
Publication |
Spectrochimica acta: part A: molecular and biomolecular spectroscopy |
Abbreviated Journal |
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Volume |
51 |
Issue |
5 |
Pages |
883-894 |
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Keywords |
A1 Journal article |
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Abstract |
In this work self-supporting tin dioxide disks are characterized using FT-IR spectroscopy in the presence of a reducing gas in air, and in different O2/N2 mixtures at temperatures varying from room temperature up to 450°C. Every factor inducing a change in the oxygen content of the gas atmosphere above the tin dioxide, as for instance a temperature change, a surface reaction or adsorption of another species, induces a broad, intense IR absorption band with discrete weak bands superimposed on it. This broad absorption is assigned to the electronic transition from a native donor level, the oxygen vacancy in the bulk of the domain, to the conduction band of the tin dioxide material. For the interpretation of the narrow, superimposed absorptions, two hypotheses remain. The results demonstrate that FT-IR spectroscopy is an extremely suitable technique for the characterization of semiconducting metal oxide sensors, since it allows to follow in situ the processes in the bulk, at the surface and in the surrounding gas atmosphere of the sensor material at working temperature as well as in the presence of reducing gases in air. |
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Wos |
A1995RJ99900014 |
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2003-04-05 |
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ISSN |
1386-1425 |
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Additional Links ![sorted by Additional Links field, ascending order (up)](img/sort_asc.gif) |
UA library record; WoS full record; WoS citing articles; WoS full record; WoS citing articles |
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Call Number |
UA @ admin @ c:irua:82015 |
Serial |
5954 |
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Author |
Delabie, L.; Honoré, M.; Lenaerts, S.; Huyberechts, G.; Roggen, J.; Maes, G. |
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Title |
The effect of sintering and Pd-doping on the conversion of CO to CO2 on SnO2 gas sensor materials |
Type |
A1 Journal article |
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Year |
1997 |
Publication |
Sensors And Actuators B-Chemical |
Abbreviated Journal |
Sensor Actuat B-Chem |
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44 |
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Pages |
446-451 |
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A1 Journal article |
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Abstract |
The principal aim of this work is to study the effect of the processes of sintering and Pd doping of SnO2 gas sensor materials on the conversion of CO to CO2. For this purpose, the gas phase above screen printed sensor material is investigated using FTIR spectroscopy, while surface area, porosity and particle size measurements are performed on the SnO2 powders. During sintering, larger agglomerates of primary particles are formed, which results in a larger conversion degree of CO. The effect of Pd doping of the tin dioxide film on the CO conversion is more pronounced. The transformation of CO starts at a lower temperature and the conversion degree increases remarkably. |
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Wos |
000071717900035 |
Publication Date |
2002-07-25 |
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Series Issue |
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Edition |
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ISSN |
0925-4005 |
ISBN |
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Additional Links ![sorted by Additional Links field, ascending order (up)](img/sort_asc.gif) |
UA library record; WoS full record; WoS citing articles; WoS full record; WoS citing articles |
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Impact Factor |
5.401 |
Times cited |
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Open Access |
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Approved |
Most recent IF: 5.401; 1997 IF: 0.858 |
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Call Number |
UA @ admin @ c:irua:82017 |
Serial |
5947 |
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Permanent link to this record |