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WO1995009361A1 - Detecteur de monoxyde d'azote no et d'ammoniac nh¿3? - Google Patents

Detecteur de monoxyde d'azote no et d'ammoniac nh¿3? Download PDF

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Publication number
WO1995009361A1
WO1995009361A1 PCT/DE1994/001115 DE9401115W WO9509361A1 WO 1995009361 A1 WO1995009361 A1 WO 1995009361A1 DE 9401115 W DE9401115 W DE 9401115W WO 9509361 A1 WO9509361 A1 WO 9509361A1
Authority
WO
WIPO (PCT)
Prior art keywords
detector
metal oxide
layer
electrodes
sensor
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/DE1994/001115
Other languages
German (de)
English (en)
Inventor
Matthias Peschke
Hans Meixner
Helmut Schmelz
Asbjörn RAMSTETTER
Monika Seidl
Bertrand Lemire
Maximilian Fleischer
Christian Dahlheim
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Siemens AG
Siemens Corp
Original Assignee
Siemens AG
Siemens Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Siemens AG, Siemens Corp filed Critical Siemens AG
Priority to EP94927487A priority Critical patent/EP0721584A1/fr
Priority to JP7510055A priority patent/JPH09503062A/ja
Priority to KR1019960701597A priority patent/KR960705206A/ko
Publication of WO1995009361A1 publication Critical patent/WO1995009361A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

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
    • G01N33/0054—Ammonia
    • 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
    • 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
    • G01N33/0037—NOx
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
    • F02B3/00—Engines characterised by air compression and subsequent fuel addition
    • F02B3/06—Engines characterised by air compression and subsequent fuel addition with compression ignition
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
    • Y02A50/00—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE in human health protection, e.g. against extreme weather
    • Y02A50/20—Air quality improvement or preservation, e.g. vehicle emission control or emission reduction by using catalytic converters

Definitions

  • the nitrogen oxide and particle emissions (dust) of a diesel engine optimized for performance and consumption can only be reduced insignificantly by means of combustion technology.
  • post-treatment of the diesel engine exhaust gases is therefore unavoidable.
  • a significant reduction in the NO x emission of an engine with excess air can be achieved by using the so-called “selective" atalytic eduction method.
  • gaseous ammonia NH3, ammonia in aqueous solution or urea as a reducing agent is injected into the exhaust system, so that the chemical reactions in particular on a catalyst
  • a NO x detector is known from / l /, the sensitive element of which consists of a mixture of the metal oxides Al2O3 and V2O5.
  • the known detector does not respond to ammonia NH3.
  • the aim of the invention is to create a detector with which both ammonia NH3 and nitrogen monoxide NO can be detected in a gas mixture. A detection of these gases should also be guaranteed if their concentration is in the ppm range.
  • a method is to be specified with which highly sensitive vanadate layers can be produced. According to the invention, these objects are achieved by a detector according to patent claim 1 and a method according to patent claim 9.
  • the advantage that can be achieved with the invention is, in particular, that the detector can still be operated without problems even at the temperatures of 500 to 600.degree Cross sensitivity to oxygen O2 and hydrogen H2 is.
  • the detector does not respond to methane CH4, carbon monoxide CO and carbon dioxide CO2.
  • methane CH4 carbon monoxide CO and carbon dioxide CO2.
  • Fig. 3 shows the comb electrodes of the detector
  • FIG. 5 the AI2O3-V2O5 sandwich structure deposited on the comb electrodes
  • FIG. 6 to 10 the sensitivity of the AIVO ⁇ thin layer of the detector produced according to the invention to nitrogen monoxide NO, ammonia NH3 and others Gases
  • Figures 1 and 2 show a detector according to the invention
  • the substrate 1 consists of a very good electrical insulating material such as glass, beryllium oxide BeO, aluminum oxide Al2O3 or silicon (with Si3N4 SiO2 insulation).
  • a vanadate layer (AIVO4 or
  • FeV ⁇ 4 as NH3 or. NO-sensitive element and a temperature sensor 4 are arranged.
  • the passivation layer made of silicon oxide denoted by 5 shields the connecting lines 6, 6 'and 7, 7' respectively assigned to the two comb electrodes 2, 2 'and the temperature sensor 4 from the oxygen present in the measuring gas.
  • the detector is actively heated with the aid of a resistance layer arranged on the back of the substrate 1.
  • the resistance layer designated 8 in FIG. 2 consists for example of platinum Pt, gold Au or an electrically conductive ceramic and has a meandering structure. Also shown is the approximately 10 to 100 nm thick and made of titanium Ti, chromium Cr, nickel Ni or tungsten W metal layer 9, which improves the adhesion between the substrate 1 and the platinum electrodes 2, 2 '.
  • the dimensions of the comb electrodes 2 and 2 ' depend on the specific resistance of the sensor layer 3 applied above them in the desired temperature range.
  • the comb structure 2, 2 ′ can have thicknesses of 0.1 to 10 ⁇ m, widths of 1 to 1000 ⁇ m and electrode spacings of 1 to 100 ⁇ m.
  • electrode thickness D 1.5 ⁇ m
  • length of the interdigital structure L 1 mm
  • electrode spacing S 50 ⁇ m.
  • FIG. 3 shows a true-to-scale illustration of an interdigital structure in a top view.
  • a resistance layer 10 made of platinum is used as the temperature sensor.
  • a 1.5 ⁇ m thick platinum layer 11 is first deposited on the heated corundum substrate 1 in a sputtering system (see FIGS. 4a, b). The structuring of this
  • Layer 11 takes place in a positive photo step, in which the photoresist 12 is applied at the location of the electrodes to be produced and exposed through a mask 13 (see FIG. 4c, d, e).
  • the developed photoresist 12 protects the platinum layer 11 during the subsequent etching step (see FIG. 4f).
  • the desired comb electrodes 2 and 2 '(see FIG. 4g) are obtained, on which the sensitive vanadate layer 3 is subsequently deposited (see FIG. 4h).
  • the use of gold Au instead of platinum Pt as the electrode material has no influence on the gas sensitivity of the vanadate layer 3.
  • the extraordinary properties of the detector according to the invention are based on the method for producing the gas-sensitive layer.
  • the sensitive layer is applied in a special sputtering process and then annealed for several hours.
  • the comb electrodes can be coated, for example, in the Leybold Z490 sputtering system.
  • Metallic vanadium V and aluminum Al serve as starting materials; H. are atomized in a plasma consisting of 80% argon and 20% oxygen from appropriate targets and are deposited on the heated substrate.
  • the sandwich structure 14 shown in FIG. 5 is built up by alternately atomizing the two targets.
  • It has a thickness of approximately 1 ⁇ m and consists of 60 to 80 V2O5 and AI2O3 layers approximately 10 to 15 nm thick, the Al2 ⁇ 3 content being 50% to a maximum of 70%.
  • the sputtering parameters are given in the table below.
  • V target 225 V.
  • the sandwich structure 14 is annealed in air in a high-temperature furnace for about 5 to 15 hours.
  • the furnace temperature has a decisive influence on the topography and the phase of the Al2O3 V2O5 layers.
  • Layers which have been annealed at temperatures T between 550 ° C. T T ⁇ 610 ° C. show an optimal sensitivity for ammonia NH3 and nitrogen monoxide NO consist of equal proportions of V2O5 and AI2O3.
  • the aluminum vanadate AIVO4 which is responsible for the high gas sensitivity, results from the tempering.
  • the maximum working temperature of the vanadate layer is about 600 ° C.
  • Layers with an Al2O3 content of more than 50% show a somewhat smaller measuring effect. However, they can also be used at higher temperatures of up to 680 ° C.
  • the following diagrams are intended to document the sensitivity or sensitivity of the AIVO4 thin films produced by the described method to different gases.
  • the size o / o (tfo: conductivity of the sensitive layer in synthetic air (80% N2 20% O2)) is plotted as a function of the time t or the concentration of the respective gas.
  • the specific resistance of the AIVO4 thin film increases in the presence of nitrogen dioxide NO2. Since the vanadate shows a completely different behavior compared to nitrogen monoxide NO (reduction in specific resistance, see FIG. 6), one can clearly distinguish the two nitrogen oxides from one another. In addition to nitrogen monoxide NO and ammonia NH3, the vanadate layer also responds to changes in the oxygen partial pressure and hydrogen H2 (see Fig. 9). The cross sensitivity to oxygen O2 and hydrogen H2 is, however, considerably less than the reaction to nitrogen monoxide NO and ammonia NH3. For example, 500 ppm hydrogen H2 in air results in almost the same change in conductivity as the addition of 10 ppm nitrogen monoxide NO.
  • FIG. 10 shows the sensitivity of the AIVO4 thin layer in moist air (80 mbar H2O) at 500 ° C. and an NO content of 10 ppm. Another gas in the specified concentration was added to the moist air within the time intervals marked by a horizontal line. Between the 80th minute and the 110th minute, for example, the air also contained 1500 ppm carbon monoxide CO in addition to the 10 ppm nitrogen monoxide NO.
  • the NO sensitivity of the AIVO4 layer is not influenced by the presence of carbon monoxide CO, methane CH4 and carbon dioxide CO2.
  • the admixture of hydrogen H2 does not mask the NO sensitivity, but a clear cross-sensitivity can be determined. A similar effect is observed with oxygen O2 when its concentration decreases from 20% to 2%.
  • the detector according to the invention can be used, for example, as an air quality sensor in a motor vehicle. Its cross-sensitivity to oxygen O2 and hydrogen H2 is not a disadvantage here, since car exhaust gases do not contain quantities of oxygen and the oxygen concentration of the exhaust gases diluted in air remains almost constant.

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  • Chemical & Material Sciences (AREA)
  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Medicinal Chemistry (AREA)
  • Food Science & Technology (AREA)
  • Analytical Chemistry (AREA)
  • Biochemistry (AREA)
  • General Health & Medical Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • Immunology (AREA)
  • Pathology (AREA)
  • Combustion & Propulsion (AREA)
  • Investigating Or Analyzing Materials By The Use Of Fluid Adsorption Or Reactions (AREA)

Abstract

On peut sensiblement réduire l'émission de Nox d'un moteur diesel par un procédé de réduction catalytique sélective. Selon ce procédé, on injecte du NH3 dans un catalyseur traversé par les gaz d'échappement, où il réagit avec NO ou NO2, se transformant en azote et en eau. Etant donné que les gaz d'échappement ne doivent contenir ni NO ni un excès de NH3, des détecteurs appropriés sont nécessaires pour contrôler la fuite de NH3 ou pour surveiller ou ajuster le dosage de NH3. A cet effet, un détecteur de monoxyde d'azote et d'ammoniac contient une couche mince en AlVO4 ou en FeVO4 comme élément sensible aux gaz. La sensibilité au NO ou au NH3 de la couche en vanadate produite par un procédé spécial de pulvérisation est supérieure de plusieurs ordres de grandeur à la sensibilité transversale à l'oxygène et à l'hydrogène. Le détecteur n'est pas sensible au méthane, au monoxyde de carbone et au dioxyde de carbone. Les effets de masquage sont également absents, c'est-à-dire que la sensibilité au NO et au NH3 du détecteur n'est pas affectée par la présence d'autres gaz. L'invention est utile comme capteur de la qualité de l'air, comme dispositif de surveillance de la fuite de NH3 et comme capteur de réglage d'un catalyseur au DENOx.
PCT/DE1994/001115 1993-09-28 1994-09-23 Detecteur de monoxyde d'azote no et d'ammoniac nh¿3? Ceased WO1995009361A1 (fr)

Priority Applications (3)

Application Number Priority Date Filing Date Title
EP94927487A EP0721584A1 (fr) 1993-09-28 1994-09-23 Detecteur de monoxyde d'azote no et d'ammoniac nh 3?
JP7510055A JPH09503062A (ja) 1993-09-28 1994-09-23 一酸化窒素ｎｏ及びアンモニアｎｈ▲下３▼を検出するための検出器
KR1019960701597A KR960705206A (ko) 1993-09-28 1994-09-23 일산화질소 및 암모니아의 검출을 위한 검출기(nitrogen monoxide no and ammonia nh_3 detector)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE4333006A DE4333006C2 (de) 1993-09-28 1993-09-28 Detektor zum Nachweis von Stickstoffmonoxid NO und Ammoniak NH3
DEP4333006.1 1993-09-28

Publications (1)

Publication Number Publication Date
WO1995009361A1 true WO1995009361A1 (fr) 1995-04-06

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Application Number Title Priority Date Filing Date
PCT/DE1994/001115 Ceased WO1995009361A1 (fr) 1993-09-28 1994-09-23 Detecteur de monoxyde d'azote no et d'ammoniac nh¿3?

Country Status (5)

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EP (1) EP0721584A1 (fr)
JP (1) JPH09503062A (fr)
KR (1) KR960705206A (fr)
DE (1) DE4333006C2 (fr)
WO (1) WO1995009361A1 (fr)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6592823B1 (en) 1998-10-09 2003-07-15 Basf Aktiengesellschaft Sensor for detecting the instantaneous concentrations of a plurality of gas constituents in a gas
WO2004029607A1 (fr) * 2002-09-30 2004-04-08 Mitsui Mining & Smelting Co., Ltd. Alcotest, procede associe de detection de la concentration d'alcool et procede de fabrication d'un detecteur de concentration d'alcool
US7074319B2 (en) * 2002-12-11 2006-07-11 Delphi Technologies, Inc. Ammonia gas sensors

Families Citing this family (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0851222A1 (fr) * 1996-12-31 1998-07-01 Corning Incorporated Detecteur d'hydrocarbures à base de métal-oxyde-semiconducteur catalytique
DE19919472C2 (de) * 1999-04-29 2001-04-19 Bosch Gmbh Robert Vorrichtung und Verfahren zur Detektion von Ammoniak
KR100534561B1 (ko) * 2002-11-28 2005-12-07 주식회사아리랑비앤에스 축사용 온도/습도/암모니아가스 측정장치
AT501921B1 (de) * 2006-05-09 2007-08-15 Avl List Gmbh Verfahren zum betreiben eines abgasnachbehandlungssystems
DE102006013698A1 (de) * 2006-03-24 2007-09-27 Robert Bosch Gmbh Gassensor
DE102006021089B4 (de) * 2006-05-05 2009-11-12 Continental Automotive Gmbh Verfahren und Vorrichtung zum Betreiben einer Brennkraftmaschine
DE102006026739B4 (de) * 2006-06-08 2008-11-27 Continental Automotive Gmbh Verfahren und Vorrichtung zum Betreiben einer Brennkraftmaschine

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4259292A (en) * 1977-01-31 1981-03-31 Tokyo Shibaura Electric Co., Ltd. Gas detecting element
JPH0545319A (ja) * 1991-08-21 1993-02-23 New Cosmos Electric Corp 半導体式アンモニアガスセンサ

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4259292A (en) * 1977-01-31 1981-03-31 Tokyo Shibaura Electric Co., Ltd. Gas detecting element
JPH0545319A (ja) * 1991-08-21 1993-02-23 New Cosmos Electric Corp 半導体式アンモニアガスセンサ

Non-Patent Citations (3)

* Cited by examiner, † Cited by third party
Title
D.GUORUI: "a study of gas sensing properties of oxide multilayer thin films", JOURNAL DE PHYSIQUE IV , COLLOQUE C2 ,SUPP. AU JOURNAL DE PHYSIQUE II ,VOL I , SEPTEMBRE 1991, vol. 2, September 1991 (1991-09-01), FRANCE, pages C-2963 - C2-968 *
PATENT ABSTRACTS OF JAPAN vol. 17, no. 338 (P - 1564) 25 June 1993 (1993-06-25) *
T.ISHIHARA ET AL: "the mixed oxide Al2O3 -V2=5 as a semiconductor gas sensor for NO and NO2", SENSORS AND ACTUATORS, vol. 19, no. 3, September 1989 (1989-09-01), LAUSANNE CH, pages 259 - 265 *

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6592823B1 (en) 1998-10-09 2003-07-15 Basf Aktiengesellschaft Sensor for detecting the instantaneous concentrations of a plurality of gas constituents in a gas
DE19846487C5 (de) * 1998-10-09 2004-12-30 Basf Ag Meßsonde für die Detektion der Momentankonzentrationen mehrerer Gasbestandteile eines Gases
WO2004029607A1 (fr) * 2002-09-30 2004-04-08 Mitsui Mining & Smelting Co., Ltd. Alcotest, procede associe de detection de la concentration d'alcool et procede de fabrication d'un detecteur de concentration d'alcool
US7074319B2 (en) * 2002-12-11 2006-07-11 Delphi Technologies, Inc. Ammonia gas sensors

Also Published As

Publication number Publication date
EP0721584A1 (fr) 1996-07-17
KR960705206A (ko) 1996-10-09
JPH09503062A (ja) 1997-03-25
DE4333006C2 (de) 1996-06-13
DE4333006A1 (de) 1995-03-30

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