Planar Pellistors : An application of electrodeposited mesoporous palladium films for the detection of combustible gases
Planar Pellistors : An application of electrodeposited mesoporous palladium films for the detection of combustible gases
The development of micromachining technologies over the past decade has led to an increasing amount of work in the field of gas sensors; for several years attempts have been made to develop a new type of catalytic gas sensor: the planar pellistor. Recently high surface area mesoporous metal films have been produced electrochemically by using lyotropic liquid crystalline phases as templating agents. Their possible use as gas sensor catalyst material has led to the present thesis.
Mesoporous palladium films were deposited electrochemically from an aqueous solution containing ammonium tetrachloropalladate and octaethyleneglycol monohexadecyl ether on various gold substrates. TEM pictures have given evidence for the existence of a mesoporous structure. Cyclic voltammetry in sulfuric acid was found to be vital in order to obtain the maximum surface area. The mesoporous palladium films were found to have an electroactive surface area between 20 and 30 m2 g-1. EQCM measurements were performed during the deposition and the treatment in sulfuric acid. A faradaic efficiency of 97% was found for the deposition and an overall loss of palladium was witnessed during cyclic voltammetry.
A micromachined planar substrate fitted with a top gold electrode to allow electrodeposition was used in combination with the mesoporous palladium films to produce the planar pellistors. Methane was used to test our sensors. Results obtained showed that the planar pellistors made with mesoporous palladium and treated in sulfuric acid responded well to the presence of methane. The response was found to be linearly proportional to the concentration of methane in air between 0 and 2.5%. The response was found to be stable and reproducible for each sensor. However reproducibility from sensor to sensor was not achieved. Response times and power consumption were found to be similar to that of commercially available pellistors. Long time exposure to air at high temperatures (ca. 500 °C) was found to dramatically affect the performances of the sensors. Bulk palladium oxide is believed to be responsible for the loss of sensitivity.
University of Southampton
1999
Guerin, Samual
(1999)
Planar Pellistors : An application of electrodeposited mesoporous palladium films for the detection of combustible gases.
University of Southampton, Doctoral Thesis.
Record type:
Thesis
(Doctoral)
Abstract
The development of micromachining technologies over the past decade has led to an increasing amount of work in the field of gas sensors; for several years attempts have been made to develop a new type of catalytic gas sensor: the planar pellistor. Recently high surface area mesoporous metal films have been produced electrochemically by using lyotropic liquid crystalline phases as templating agents. Their possible use as gas sensor catalyst material has led to the present thesis.
Mesoporous palladium films were deposited electrochemically from an aqueous solution containing ammonium tetrachloropalladate and octaethyleneglycol monohexadecyl ether on various gold substrates. TEM pictures have given evidence for the existence of a mesoporous structure. Cyclic voltammetry in sulfuric acid was found to be vital in order to obtain the maximum surface area. The mesoporous palladium films were found to have an electroactive surface area between 20 and 30 m2 g-1. EQCM measurements were performed during the deposition and the treatment in sulfuric acid. A faradaic efficiency of 97% was found for the deposition and an overall loss of palladium was witnessed during cyclic voltammetry.
A micromachined planar substrate fitted with a top gold electrode to allow electrodeposition was used in combination with the mesoporous palladium films to produce the planar pellistors. Methane was used to test our sensors. Results obtained showed that the planar pellistors made with mesoporous palladium and treated in sulfuric acid responded well to the presence of methane. The response was found to be linearly proportional to the concentration of methane in air between 0 and 2.5%. The response was found to be stable and reproducible for each sensor. However reproducibility from sensor to sensor was not achieved. Response times and power consumption were found to be similar to that of commercially available pellistors. Long time exposure to air at high temperatures (ca. 500 °C) was found to dramatically affect the performances of the sensors. Bulk palladium oxide is believed to be responsible for the loss of sensitivity.
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Published date: 1999
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Local EPrints ID: 464073
URI: http://eprints.soton.ac.uk/id/eprint/464073
PURE UUID: c41c6218-6392-46c9-9b1d-2e6b947314e6
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Date deposited: 04 Jul 2022 21:02
Last modified: 04 Jul 2022 21:02
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Author:
Samual Guerin
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