DE10011164A1 - Process for determining the hydrogen concentration in fluid media comprises using a sensor consisting of a supported hydrogen activated metal and a hydrogen storing support material provided with two connecting electrodes - Google Patents
Process for determining the hydrogen concentration in fluid media comprises using a sensor consisting of a supported hydrogen activated metal and a hydrogen storing support material provided with two connecting electrodesInfo
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- DE10011164A1 DE10011164A1 DE2000111164 DE10011164A DE10011164A1 DE 10011164 A1 DE10011164 A1 DE 10011164A1 DE 2000111164 DE2000111164 DE 2000111164 DE 10011164 A DE10011164 A DE 10011164A DE 10011164 A1 DE10011164 A1 DE 10011164A1
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- hydrogen
- sensor
- supported
- determining
- concentration
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Links
- 239000001257 hydrogen Substances 0.000 title claims abstract description 44
- 229910052739 hydrogen Inorganic materials 0.000 title claims abstract description 44
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 title claims abstract description 41
- 238000000034 method Methods 0.000 title claims abstract description 24
- 239000000463 material Substances 0.000 title claims abstract description 16
- 239000002184 metal Substances 0.000 title claims abstract description 15
- 229910052751 metal Inorganic materials 0.000 title claims abstract description 15
- 239000012530 fluid Substances 0.000 title claims abstract description 13
- 230000008569 process Effects 0.000 title abstract description 5
- 239000010457 zeolite Substances 0.000 claims abstract description 16
- 229910021536 Zeolite Inorganic materials 0.000 claims abstract description 11
- HNPSIPDUKPIQMN-UHFFFAOYSA-N dioxosilane;oxo(oxoalumanyloxy)alumane Chemical compound O=[Si]=O.O=[Al]O[Al]=O HNPSIPDUKPIQMN-UHFFFAOYSA-N 0.000 claims abstract description 11
- 238000002847 impedance measurement Methods 0.000 claims abstract description 10
- 238000001566 impedance spectroscopy Methods 0.000 claims abstract description 6
- 238000005259 measurement Methods 0.000 claims description 13
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 claims description 12
- 239000012876 carrier material Substances 0.000 claims description 7
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 6
- 230000003213 activating effect Effects 0.000 claims description 6
- 150000001875 compounds Chemical class 0.000 claims description 4
- 229910052697 platinum Inorganic materials 0.000 claims description 4
- PNEYBMLMFCGWSK-UHFFFAOYSA-N Alumina Chemical class [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 claims description 3
- BPQQTUXANYXVAA-UHFFFAOYSA-N Orthosilicate Chemical compound [O-][Si]([O-])([O-])[O-] BPQQTUXANYXVAA-UHFFFAOYSA-N 0.000 claims description 2
- 238000012986 modification Methods 0.000 claims description 2
- 230000004048 modification Effects 0.000 claims description 2
- 235000012239 silicon dioxide Nutrition 0.000 claims description 2
- 239000000377 silicon dioxide Substances 0.000 claims description 2
- 230000003197 catalytic effect Effects 0.000 claims 1
- 239000012229 microporous material Substances 0.000 claims 1
- 239000011232 storage material Substances 0.000 claims 1
- 238000001514 detection method Methods 0.000 abstract description 3
- 238000000465 moulding Methods 0.000 abstract 1
- 239000007789 gas Substances 0.000 description 11
- 150000002500 ions Chemical class 0.000 description 4
- 239000003570 air Substances 0.000 description 3
- 239000003990 capacitor Substances 0.000 description 3
- 150000002431 hydrogen Chemical class 0.000 description 3
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 2
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- KDLHZDBZIXYQEI-UHFFFAOYSA-N Palladium Chemical compound [Pd] KDLHZDBZIXYQEI-UHFFFAOYSA-N 0.000 description 2
- 230000008901 benefit Effects 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 239000002800 charge carrier Substances 0.000 description 2
- 230000001419 dependent effect Effects 0.000 description 2
- 238000003958 fumigation Methods 0.000 description 2
- 238000005342 ion exchange Methods 0.000 description 2
- 238000000691 measurement method Methods 0.000 description 2
- 239000012071 phase Substances 0.000 description 2
- 239000007787 solid Substances 0.000 description 2
- 239000002253 acid Substances 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 239000012190 activator Substances 0.000 description 1
- 150000004645 aluminates Chemical class 0.000 description 1
- 239000007864 aqueous solution Substances 0.000 description 1
- 229910052786 argon Inorganic materials 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 238000004364 calculation method Methods 0.000 description 1
- 238000011088 calibration curve Methods 0.000 description 1
- 230000015556 catabolic process Effects 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 239000000084 colloidal system Substances 0.000 description 1
- 230000002596 correlated effect Effects 0.000 description 1
- 230000000875 corresponding effect Effects 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- ZINJLDJMHCUBIP-UHFFFAOYSA-N ethametsulfuron-methyl Chemical compound CCOC1=NC(NC)=NC(NC(=O)NS(=O)(=O)C=2C(=CC=CC=2)C(=O)OC)=N1 ZINJLDJMHCUBIP-UHFFFAOYSA-N 0.000 description 1
- 230000005284 excitation Effects 0.000 description 1
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 description 1
- 239000010931 gold Substances 0.000 description 1
- 229910052737 gold Inorganic materials 0.000 description 1
- 238000005470 impregnation Methods 0.000 description 1
- 238000010978 in-process monitoring Methods 0.000 description 1
- 230000003993 interaction Effects 0.000 description 1
- 239000010416 ion conductor Substances 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 239000007791 liquid phase Substances 0.000 description 1
- 230000028161 membrane depolarization Effects 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 229910052763 palladium Inorganic materials 0.000 description 1
- 235000011837 pasties Nutrition 0.000 description 1
- 230000010287 polarization Effects 0.000 description 1
- 239000010970 precious metal Substances 0.000 description 1
- 230000001681 protective effect Effects 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 238000005316 response function Methods 0.000 description 1
- 230000002441 reversible effect Effects 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
- 150000004760 silicates Chemical class 0.000 description 1
- 229910052665 sodalite Inorganic materials 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
- 230000003595 spectral effect Effects 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 230000036962 time dependent Effects 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
- G01N33/0004—Gaseous mixtures, e.g. polluted air
- G01N33/0009—General constructional details of gas analysers, e.g. portable test equipment
- G01N33/0027—General constructional details of gas analysers, e.g. portable test equipment concerning the detector
- G01N33/0036—General constructional details of gas analysers, e.g. portable test equipment concerning the detector specially adapted to detect a particular component
- G01N33/005—H2
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
- G01N27/02—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance
- G01N27/04—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance
- G01N27/12—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance of a solid body in dependence upon absorption of a fluid; of a solid body in dependence upon reaction with a fluid, for detecting components in the fluid
Landscapes
- Chemical & Material Sciences (AREA)
- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- General Health & Medical Sciences (AREA)
- Immunology (AREA)
- Engineering & Computer Science (AREA)
- Analytical Chemistry (AREA)
- Biochemistry (AREA)
- Pathology (AREA)
- General Physics & Mathematics (AREA)
- Physics & Mathematics (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- Combustion & Propulsion (AREA)
- Food Science & Technology (AREA)
- Medicinal Chemistry (AREA)
- Investigating Or Analyzing Materials By The Use Of Electric Means (AREA)
- Investigating Or Analyzing Materials By The Use Of Fluid Adsorption Or Reactions (AREA)
Abstract
Description
Die Erfindung betrifft ein hochselektives Verfahren zum Nachweis von Wasserstoff und zur Bestimmung der Wasserstoffkonzentration in fluiden Medien, das insbesondere in der Prozeßüberwachung, z. B. in der chemischen Industrie, Anwendung finden kann.The invention relates to a highly selective method for Detection of hydrogen and determination of Hydrogen concentration in fluid media, that especially in process monitoring, e.g. B. in the chemical industry.
Gegenstand der Erfindung ist auch ein Sensor zur Anwendung im erfindungsgemäßen Verfahren. Als fluide Medien werden im Sinne der Erfindung Gase wie z. B. wasserstoffhaltige Prozeßgase, und Flüssigkeiten ver standen.The invention also relates to a sensor for Use in the method according to the invention. As fluid Media are in the sense of the invention gases such. B. process gases containing hydrogen, and liquids ver stood.
Es ist bekannt, die Konzentrationsmessung von redu zierenden Gasen, wie z. B. Wasserstoff, in fluiden Medien über die elektronische Leitfähigkeit von Metall- Halbleiter-Systemen durchzuführen (vgl. US 3,631,436). Dabei wird entsprechend einer Kalibrierkurve ein gemessener Widerstandswert mit der Konzentration des reduzierenden Gases (z. B. Wasserstoff) korreliert. It is known to measure the concentration of redu ornamental gases, such as B. hydrogen in fluids Media about the electronic conductivity of metal Perform semiconductor systems (see. US 3,631,436). In doing so, a corresponding to a calibration curve measured resistance value with the concentration of the reducing gas (e.g. hydrogen) correlated.
In der Regel wird die Wirkung der reduzierenden Gase in Luft dabei über die Konzentration des chemisorbierten Sauerstoffs, die wiederum die Elektronenkonzentration beeinflußt, bestimmt. Diese Interpretation des Wirkprinzips (s. Mc Aleer et al., J. Chem. Soc., Faraday Trans. 1987, 83, 1323) dürfte auch auf das o. g. Patent zutreffen. Der Nachteil dieser Methode besteht darin, daß der Sensor auf eine Vielzahl von weiteren reduzierenden Gasen neben Wasserstoff anspricht (Querempfindlichkeit).As a rule, the effect of the reducing gases in air is determined via the concentration of the chemisorbed oxygen, which in turn influences the electron concentration. This interpretation of the principle of action (see Mc Aleer et al., J. Chem. Soc., Faraday Trans. 1987, 83 , 1323) should also apply to the above-mentioned patent. The disadvantage of this method is that the sensor responds to a large number of other reducing gases in addition to hydrogen (cross-sensitivity).
Eine weitere bekannte Möglichkeit zur Messung der Konzentration von reduzierenden Gasen in Luft besteht in der Messung bei der Oxidation des reduzierenden Gases entstehenden Wärme (s. z. B. Göpel, Techn. Messen, 1983, 52, 47 und 92). Diese Meßmethode liefert jedoch kein für die Art des oxidierten Gases spezifisches Meßsignal.Another known possibility for measuring the concentration of reducing gases in air is to measure the heat generated during the oxidation of the reducing gas (see, for example, Göpel, Techn. Messen, 1983, 52 , 47 and 92). However, this measurement method does not provide a measurement signal specific to the type of oxidized gas.
Aufgabe der vorliegenden Erfindung war es, ein selektives Verfahren zur Detektion von Wasserstoff und zur Bestimmung der Wasserstoffkonzentration in fluiden Medien bereitzustellen.The object of the present invention was to selective method for the detection of hydrogen and to determine the hydrogen concentration in fluids To provide media.
Erfindungsgemäß wird ein Verfahren bereitgestellt, das es erlaubt, die protonenbasierte Leitfähigkeit zu messen und das nicht auf der Messung der elektronischen Leitfähigkeit basiert wie die meisten bisher bekannten Verfahren des Standes der Technik. According to the invention, a method is provided that it allows the proton based conductivity to measure and not on the measurement of electronic Conductivity is based like most previously known State of the art methods.
Die erfindungsgemäße Methode der Bestimmung der Wasserstoffkonzentration bietet den Vorteil, daß sie gegenüber Wasserstoff und dessen Isotopen hoch selektiv ist.The method of determining the invention Hydrogen concentration has the advantage that it highly selective towards hydrogen and its isotopes is.
Das erfindungsgemäße Verfahren zur Bestimmung der Wasserstoffkonzentration ist dadurch gekennzeichnet, daß ein Sensor in Form einer Schicht oder eines kompakten Festkörpers oder Formlings mit Elektroden versehen wird, wobei der Sensor aus einem Wasserstoff speichernden Trägermaterial und aus einem geträgerten Wasserstoff aktivierenden Metall besteht, dann mit dem zu bestimmenden Wasserstoff enthaltenden fluiden Medium begast wird und mittels Impedanzmessung die Protonen konzentration bzw. -beweglichkeit an der Oberfläche des Sensors gemessen wird.The inventive method for determining the Hydrogen concentration is characterized by that a sensor in the form of a layer or a compact solid or molded article with electrodes is provided, the sensor being made of a hydrogen storing carrier material and from a carrier Hydrogen activating metal, then with the fluid medium to be determined containing hydrogen is fumigated and the protons by means of impedance measurement concentration or mobility on the surface of the Sensor is measured.
Zur Messung wird der Sensor mit einem wasserstoff haltigen fluiden Medium in Kontakt gebracht (z. B.. im nachfolgenden Anwendungsbeispiel 5% Wasserstoff in Argon) und dabei der komplexe Widerstand (Impedanz) Z*, vorzugsweise als Funktion der Frequenz, gemessen. Je nach Probenbeschaffenheit, -geometrie und Meßproblem kann sich die Darstellung der Meßdaten in einer anderen, impedanzverwandten Größe als zweckmäßig erwei sen. Dabei kann es sich um den komplexen Modulus M*, die komplexe Permittivität E* oder die komplexe Admit tanz Y*, gegebenenfalls in spektraler Darstellung, handeln. Die Umrechnung dieser Größen ineinander erfolgt nach den in der elektronischen Meßtechnik üblichen Formeln. Beim Begasen entstehen durch das Zusammenwirken von Metall und Träger H+-Ionen auf dem Träger. Dies führt zu einer Erhöhung der Leitfähigkeit, die auf der Beweglichkeit der H+-Ionen beruht.For the measurement, the sensor is brought into contact with a hydrogen-containing fluid medium (eg 5% hydrogen in argon in the following application example) and the complex resistance (impedance) Z *, preferably as a function of frequency, is measured. Depending on the nature of the sample, its geometry and the measurement problem, the representation of the measurement data in a different, impedance-related size may prove to be useful. This can be the complex modulus M *, the complex permittivity E * or the complex admittance Y *, possibly in a spectral representation. These quantities are converted into one another using the formulas customary in electronic measurement technology. During gassing, the interaction of metal and carrier creates H + ions on the carrier. This leads to an increase in conductivity based on the mobility of the H + ions.
Gemäß dem erfindungsgemäßen Verfahren erfolgt in einem Temperaturbereich bis zur thermischen Stabilitätsgrenze des Sensormaterials, vorzugsweise zwischen Raumtempera tur und 400°C, eine Meßwertaufnahme mittels Impedanz spektroskopie in einem Frequenzbereich zwischen 10-5 und 1011 Hz, vorzugsweise zwischen 10 und 107 Hz. Die dabei angewandten Meßspannungen sind durch die Durch bruchfeldstärke des Sensormaterials begrenzt, vorzugs weise werden Spannungen zwischen 10 mv und 1 V einge setzt. Die Begasungsdauer ist sensortyp- und prozeß abhängig, sie kann je nach Anwendungsfall zwischen einigen Sekunden und mehreren Stunden liegen.According to the inventive method takes place in a temperature range up to the thermal stability limit of the sensor material, preferably between room temperature and 400 ° C, a measured value recording by means of impedance spectroscopy in a frequency range between 10 -5 and 10 11 Hz, preferably between 10 and 10 7 Hz the applied measuring voltages are limited by the breakdown strength of the sensor material, preferably voltages between 10 mv and 1 V are used. The fumigation time depends on the type of sensor and the process. Depending on the application, it can be between a few seconds and several hours.
Erfindungsgemäß wird also die Bildung beweglicher Ladungsträger (H+-Ionen) mit Hilfe der Impedanzspek troskopie direkt nachgewiesen. Das angewandte Impedanz meßprinzip liefert ein elektrisches Signal als wasser stoffkonzentrationsabhängige Meßgröße. Das Impedanzmeß prinzip umfaßt dabei alle Meßverfahren auf der Grund lage von Einzelfrequenzmessungen nach Betrag und Pha senwinkel von Strom und Spannung sowie Methoden zur Bestimmung des realen, imaginären bzw. des komplexen Wechselstromwiderstandes in einem Frequenzbereich zwischen 10-5 Hz und 1010 Hz sowie Methoden, die auf der Messung von Polarisations- oder Depolarisationsströmen beruhen (frequency-domain- und time-domain-Methoden). According to the invention, the formation of mobile charge carriers (H + ions) is detected directly with the aid of impedance spectroscopy. The applied impedance measurement principle delivers an electrical signal as a hydrogen-dependent measurement variable. The impedance measurement principle includes all measurement methods based on single frequency measurements according to the amount and phase angle of current and voltage, as well as methods for determining the real, imaginary or complex AC resistance in a frequency range between 10 -5 Hz and 10 10 Hz and methods, which are based on the measurement of polarization or depolarization currents (frequency domain and time domain methods).
All diese Methoden sind mit dem Sammelbegriff Impedanz spektroskopie erfaßt.All of these methods are collectively called impedance spectroscopy recorded.
Die Vorteile dieses Meßsystems sind auch darin begrün det, daß als Träger für den Wasserstoffaktivator oxidische Materialien verwendet werden, die zu der Gruppe der elektronischen Isolatoren gehören bzw. z. T. Ionenleiter sind.The advantages of this measuring system are also green det that as a carrier for the hydrogen activator oxidic materials are used, which lead to the Group of electronic isolators belong or z. T. Are ionic conductors.
Erfindungsgemäß wird als Wasserstoff speicherndes Trägermaterial vorzugsweise ein mikroporöses oder mesoporöses oxidisches Material eingesetzt. Als mikro poröses oxidisches Material kommen dabei silikatische oder alumosilikatische Verbindungen in Frage, insbe sondere Zeolithe. Als Zeolithe werden besonders bevor zugt Zeolithe des Typs ZSM-5, Y, X, A, Beta, Silikalit oder Sodalith eingesetzt. Auch zeolithverwandte Oxide mit Gerüststruktur wie Antimonate, Tantalate, Gallate, Aluminate oder Niobate können Verwendung finden, ebenso wie zeolithverwandte Oxide mit Schichtstruktur, wie beispielsweise Aluminiumoxide oder Schichtsilikate.According to the invention it is stored as hydrogen Carrier material preferably a microporous or Mesoporous oxidic material used. As a micro porous oxidic material come here silicate or alumosilicate compounds in question, esp special zeolites. As zeolites are especially before adds zeolites of the type ZSM-5, Y, X, A, Beta, silicalite or sodalite used. Also zeolite-related oxides with framework structure such as antimonates, tantalates, gallates, Aluminates or niobates can be used as well such as zeolite-related oxides with a layer structure, such as for example aluminum oxides or layered silicates.
Als mesoporöses oxidisches Trägermaterial werden erfin dungsgemäß siliatische, alumosilikatische oder borosi likatische Verbindungen eingesetzt, vorzugsweise Verbindungen des MCM-41-Strukturtyps, Aluminiumoxide oder Modifikationen des Siliziumdioxids.As a mesoporous oxidic carrier material are invented according to the siliatic, alumosilicate or borosi likatic compounds used, preferably MCM-41 structure type compounds, aluminum oxides or modifications of the silicon dioxide.
Als Wasserstoff aktivierendes Metall, das auf dem oxi dischen Träger aufgebracht wird, wird vorzugsweise ein Element der 8. Nebengruppe, z. B. Platin oder Palla dium, eingesetzt. As a hydrogen activating metal that is on the oxi The carrier is applied, is preferably a Element of the 8th subgroup, e.g. B. platinum or palla dium, used.
Das Aufbringen des Metalls auf den oxidischen Träger kann in ionischer Form durch Ionenaustausch, Tränkim prägnierung oder Festkörperionenaustausch und an schließende Reduktion erfolgen.The application of the metal to the oxide carrier can be in ionic form by ion exchange, Tränkim impregnation or solid ion exchange and at closing reduction.
Es ist auch möglich, die Metalle auf den Träger in Form von Metallclustern oder Metallkolloiden aus der Gasphase oder der flüssigen Phase in an sich bekannter Art und Weise aufzubringen.It is also possible to shape the metals onto the carrier of metal clusters or metal colloids from the Gas phase or the liquid phase in known per se Way to muster.
Der so hergestellte Sensor wird dann in vorzugsweiser pastöser Form als Schicht auf die Edelmetallelektroden des Kondensators, vorzugsweise eines Interdigital kondensators, aufgebracht und ausgeheizt. Dann erfolgt die Impedanzmessung wie oben beschrieben.The sensor produced in this way is then preferred pasty form as a layer on the precious metal electrodes the capacitor, preferably an interdigital capacitor, applied and baked out. Then done the impedance measurement as described above.
Gegenstand der Erfindung ist auch der beschriebene Sensor und seine Verwendung zur Bestimmung der Wasserstoffkonzentration in fluiden Medien mittels Impedanzmessung.The invention also relates to the one described Sensor and its use to determine the Hydrogen concentration in fluid media using Impedance measurement.
2 g eines H-ZSM-5-Zeolithen wurden mit 20 mL einer wäßrigen Lösung von Hexachloroplatinsäure getränkt. Die Lösung wurde eingeengt und der platinbeladene Zeolith (Pt/ZSM-5) für 3 h bei 485 K getrocknet. Anschließend wurde der Pt/H-ZSM-5-Zeolith in einem Durchflußreaktor bei 723 K konsekutiv mit Luft, Stickstoff und Wasserstoff behandelt. Aus dem reduzierten Pt/H-ZSM-5- Zeolith wurden anschließend Dickfilm-Proben für die Impedanzmessung hergestellt, indem der Pt/H-ZSM-5 in Wasser dispergiert und die Paste auf die Goldelektroden eines Interdigitalkondensators gebracht wurde. Nach Trocknung der Schicht wurde der Sensor zunächst für 12 Stunden unter Schutzgas (Ar) auf 673 K erhitzt. Die Messung der komplexen Impedanz an den ausgeheizten Proben zeigt die für Zeolithe typische Antwortfunktion, die die Beweglichkeit der Ionen im Zeolithen mit den typischen Relaxationszeiten und Anregungsenergien wi derspiegelt. Durch Zugabe von Wasserstoff erhöht sich die Leitfähigkeit bei hohen Frequenzen, was bei spielsweise in der Darstellung der Impedanzmeßdaten als Imaginärteil des komplexen Modulus (M") versus Meß frequenz visualisiert werden kann (vgl. Abb. 1). Die Leitfähigkeitszunahme, die ihre Ursache nach dem heutigen Stand der Kenntnis in der Bildung mobiler Ladungsträger (Protonen) unter Begasung mit Wasserstoff hat, ist reversibel und konzentrationsabhängig.2 g of an H-ZSM-5 zeolite were impregnated with 20 ml of an aqueous solution of hexachloroplatinic acid. The solution was concentrated and the platinum-loaded zeolite (Pt / ZSM-5) was dried at 485 K for 3 h. The Pt / H-ZSM-5 zeolite was then treated in a flow reactor at 723 K consecutively with air, nitrogen and hydrogen. Thick film samples for the impedance measurement were then produced from the reduced Pt / H-ZSM-5 zeolite by dispersing the Pt / H-ZSM-5 in water and applying the paste to the gold electrodes of an interdigital capacitor. After the layer had dried, the sensor was first heated to 673 K under protective gas (Ar) for 12 hours. The measurement of the complex impedance on the heated samples shows the response function typical for zeolites, which reflects the mobility of the ions in the zeolite with the typical relaxation times and excitation energies. The addition of hydrogen increases the conductivity at high frequencies, which can be visualized, for example, in the representation of the impedance measurement data as an imaginary part of the complex modulus (M ") versus measurement frequency (see Fig. 1). The increase in conductivity, which is the cause The current state of knowledge in the formation of mobile charge carriers (protons) with gassing with hydrogen is reversible and concentration-dependent.
Abb. 1 zeigt den zeitabhängigen Einfluß des Wasser stoffs auf das Meßsignal für das vorliegende Beispiel. Dabei wurde ein Widerstandswert R aus dem Modulus M* gemäß dem bekannten Berechnungsverfahren (siehe Macdonald, "Impedance Spectroscopy", John Wiley & Sons, 1987) bestimmt. Fig. 1 shows the time-dependent influence of the hydrogen on the measurement signal for the present example. A resistance value R was determined from the modulus M * in accordance with the known calculation method (see Macdonald, "Impedance Spectroscopy", John Wiley & Sons, 1987).
Im einzelnen bedeuten:
ΔR die Widerstandsänderung und
R0 den Ausgangswiderstand des Sensors.
In particular:
ΔR the change in resistance and
R 0 the output resistance of the sensor.
Aus der Abbildung wird deutlich, daß der Widerstand unter Begasung mit Wasserstoff mit der Zeit abnimmt und nach dem Abschalten des Wasserstoffs wieder zunimmt.From the figure it is clear that the resistance with fumigation with hydrogen decreases over time and after switching off the hydrogen increases again.
Claims (10)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE2000111164 DE10011164B4 (en) | 2000-02-28 | 2000-02-28 | Method and sensor for determining the hydrogen concentration in fluid media |
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| DE2000111164 DE10011164B4 (en) | 2000-02-28 | 2000-02-28 | Method and sensor for determining the hydrogen concentration in fluid media |
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| DE10011164A1 true DE10011164A1 (en) | 2001-09-13 |
| DE10011164B4 DE10011164B4 (en) | 2004-01-29 |
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| DE (1) | DE10011164B4 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP3754329A1 (en) * | 2019-06-21 | 2020-12-23 | Materion GmbH | Hydrogen sensor and method for producing the same, measuring device and method for measuring hydrogen concentration |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3631436A (en) * | 1970-07-14 | 1971-12-28 | Naoyoshi Taguchi | Gas-detecting device |
| US6173602B1 (en) * | 1998-08-11 | 2001-01-16 | Patrick T. Moseley | Transition metal oxide gas sensor |
-
2000
- 2000-02-28 DE DE2000111164 patent/DE10011164B4/en not_active Expired - Fee Related
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP3754329A1 (en) * | 2019-06-21 | 2020-12-23 | Materion GmbH | Hydrogen sensor and method for producing the same, measuring device and method for measuring hydrogen concentration |
| US11428659B2 (en) | 2019-06-21 | 2022-08-30 | Materion Gmbh | Hydrogen sensor and method for its production, measuring device, and method for measuring a hydrogen concentration |
Also Published As
| Publication number | Publication date |
|---|---|
| DE10011164B4 (en) | 2004-01-29 |
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