EP0843813A1 - Detecteur pour determiner la concentration de constituants oxydables d'un melange gazeux - Google Patents

Detecteur pour determiner la concentration de constituants oxydables d'un melange gazeux

Info

Publication number
EP0843813A1
EP0843813A1 EP97923831A EP97923831A EP0843813A1 EP 0843813 A1 EP0843813 A1 EP 0843813A1 EP 97923831 A EP97923831 A EP 97923831A EP 97923831 A EP97923831 A EP 97923831A EP 0843813 A1 EP0843813 A1 EP 0843813A1
Authority
EP
European Patent Office
Prior art keywords
sensor according
semiconductor
measuring
acceptor
donor
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.)
Withdrawn
Application number
EP97923831A
Other languages
German (de)
English (en)
Inventor
Bernd Schumann
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.)
Robert Bosch GmbH
Original Assignee
Robert Bosch GmbH
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 Robert Bosch GmbH filed Critical Robert Bosch GmbH
Publication of EP0843813A1 publication Critical patent/EP0843813A1/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • GPHYSICS
    • G01MEASURING; TESTING
    • G01NINVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N27/00Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
    • G01N27/26Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating electrochemical variables; by using electrolysis or electrophoresis
    • G01N27/403Cells and electrode assemblies
    • G01N27/406Cells and probes with solid electrolytes
    • G01N27/407Cells and probes with solid electrolytes for investigating or analysing gases
    • G01N27/4073Composition or fabrication of the solid electrolyte
    • G01N27/4074Composition or fabrication of the solid electrolyte for detection of gases other than oxygen
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01NINVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N27/00Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
    • G01N27/26Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating electrochemical variables; by using electrolysis or electrophoresis
    • G01N27/403Cells and electrode assemblies
    • G01N27/406Cells and probes with solid electrolytes
    • G01N27/407Cells and probes with solid electrolytes for investigating or analysing gases
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01NINVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N27/00Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
    • G01N27/26Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating electrochemical variables; by using electrolysis or electrophoresis
    • G01N27/403Cells and electrode assemblies
    • G01N27/406Cells and probes with solid electrolytes
    • G01N27/407Cells and probes with solid electrolytes for investigating or analysing gases
    • G01N27/4071Cells and probes with solid electrolytes for investigating or analysing gases using sensor elements of laminated structure

Definitions

  • the invention is based on a sensor for determining the concentration of oxidizable constituents in a gas mixture, in particular for determining one or more of the gases NOx, CO, H2 and preferably unsaturated hydrocarbons according to the type of the main claim.
  • Exhaust gases from gasoline and diesel engines, internal combustion engines and combustion systems can cause increased concentrations of oxidizable constituents, in particular NOx, CO, H2 and hydrocarbons, for example as a result of a component malfunction, such as an injection valve, or as a result of incomplete combustion. To optimize the combustion reactions, it is therefore necessary to know the concentration of these exhaust gas components.
  • JP-OS 60-61654 describes a method for determining oxidizable gases, according to which an ⁇ tochiometric reaction with oxygen takes place on a first measuring electrode made of platinum metals and on one or more further metallic measuring electrodes with reduced catalytic activity for the oxygen equilibrium reaction quasi-equilibrium states can be set. There are the Nernst voltages El and E2 between the measuring electrodes and a reference electrode measured, which is exposed to a reference gas with constant oxygen partial pressure, and from their difference based on calibration curves, the concentration of the gas components is calculated.
  • the senor according to the invention with the features of the main claim has improved analytical performance features, in particular a higher sensitivity and selectivity with respect to individual sample gas components to be determined.
  • Sensitivity and selectivity of the measuring electrodes are improved by doping the in particular oxidic or mixed-oxide semiconductors with acceptors and / or donors.
  • the conductivity of the measuring electrodes is improved by adding donors, especially in higher concentrations compared to the acceptors.
  • Particularly powerful electrodes are obtained if the acceptor is selected from the range of transition metals and / or rare earths and / or the donor is one or both of the elements tantalum and niobium.
  • An increased miniaturization, a simplification of construction and a less expensive production are achieved by sintering the solid electrolyte porous.
  • the thermodynamic equilibrium can advantageously also be set in the solid electrolyte by selecting a catalytically active solid electrolyte material.
  • a particular advantage is that the gases that disturb the reference signal can be oxidized in a targeted manner, which simplifies signal evaluation or even makes it possible in the first place.
  • the measuring electrodes can also be porous, which further improves the diffusion of the molecules of the measuring gas to the reference electrode. By adding additives to the solid electrolyte in the areas adjacent to the electrodes which correspond to the electrode materials, the electrode adhesion and thus the life of the sensor is improved.
  • Figure 1 shows a section through a sensor according to the invention.
  • a sensor according to the invention is shown in section in FIG.
  • An electrically insulating planar ceramic substrate 6 carries a reference electrode 3 made of, for example, platinum, a solid electrolyte 5, on one large surface in layers one above the other.
  • a heater device 7 with a cover ⁇ is applied to the opposite large surface of the substrate.
  • the solid electrolyte can be sintered porously, but the person skilled in the art can also choose other solutions known to him, such as via a reference channel or a reference gas atmosphere.
  • the sensor generates a cell voltage above the oxygen ion-conducting solid electrolyte by means of a first half-cell reaction set with the aid of the reference electrode and a second half-cell reaction on at least one measuring electrode influenced by the oxidizable gas components to be determined.
  • the calibration values are used to determine the concentrations of the gas components from the voltage values.
  • the sensor according to the invention is thus in the simplest case with a reference electrode which
  • measuring electrodes as shown in FIG. 1, or also several measuring electrodes, each with different catalytic activity, for setting oxygen Equilibrium states.
  • the measuring electrodes then react with different voltages depending on the type of gas, based on the reference electrode.
  • the solid electrolyte is formed, e.g. by adding 0.01 to 10% by volume of platinum so that the solid electrolyte converts the gases to be measured catalytically, so that only the gases corresponding to the thermodynamic equilibrium arrive at the reference electrode or that the solid electrolyte only converts the gases which disturb the reference signal.
  • one or more measuring electrodes are made porous in addition to the solid electrolyte, thereby facilitating gas diffusion to the reference electrode.
  • Semiconductors which have a high specific sensitivity for certain oxidizable gases are used as measuring electrode materials.
  • Oxides or mixed oxides, in particular based on rutile or dirutile or mixtures thereof, which can be doped with acceptor and / or donor are particularly suitable. Titanium and / or zirconium dioxide are advantageously used.
  • Suitable donors are in particular tantalum and niobium, preferably elements with higher valence than the metals forming the semiconductor; suitable acceptors are transition metals, in particular nickel, copper, cobalt and / or chromium, preferably nickel, copper and / or cobalt, and rare earths.
  • the acceptor can be contained in the semiconductor as a solid solution or as a segregated component.
  • the concentrations of the acceptors and donors are each in the range from 0.01 to 25%; at lower proportions, there is no improvement in the properties of the measuring electrodes, and at higher proportions grid defects occur.
  • the high sensitivity of e.g. Acceptor and donor-doped titanium dioxide for unsaturated hydrocarbons in particular is caused by the adsorptive interaction of the orbitals of the Pi bonds of the unsaturated hydrocarbons with the electrophilic acceptor sites on the semiconductor surface.
  • the following example describes a production method for a sensor according to the invention: Rutile doped with 7% niobium and 3% of one of the transition metals nickel, copper or iron is printed as a 30 ⁇ m thick screen printing layer on a substrate which has a reference electrode, for example made of platinum, and above it Solid electrolyte layer carries. A heater device is applied to the opposite side of the substrate. The sensor is sintered at 1200 ° C for 90 minutes with a heating / cooling ramp of 300 ° C / hour.
  • the solid electrolyte After sintering, the solid electrolyte has pores in the size range from 10 nm to 100 ⁇ m. With the aid of a platinum conductor track insulated from the solid electrolyte and which only contacts the measuring electrode, the voltage across the cell thus constructed is measured at a resistance of 1 MOhm between the reference and the rutile electrode. The sensor is heated to 600 ° C with its heater.
  • Simulated exhaust gas with 10% oxygen, 5% water and 5% carbon dioxide and 30 ppm sulfur dioxide is used as the measurement gas.
  • Oxidizable gases are mixed in the amounts given in the table.
  • the last line of the table below shows the voltage values for a mixed potential electrode made of 20% gold and 80% platinum, which represents a measuring electrode according to the prior art.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Health & Medical Sciences (AREA)
  • Physics & Mathematics (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • Molecular Biology (AREA)
  • Analytical Chemistry (AREA)
  • Biochemistry (AREA)
  • General Health & Medical Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • Immunology (AREA)
  • Pathology (AREA)
  • Measuring Oxygen Concentration In Cells (AREA)
  • Investigating Or Analyzing Materials By The Use Of Fluid Adsorption Or Reactions (AREA)

Abstract

L'invention concerne un détecteur pour déterminer la concentration de constituants oxydables d'un mélange gazeux, notamment pour déterminer la présence d'un ou plusieurs des gaz NOx, CO, H2 et de préférence d'hydrocarbures insaturés, par mesure de la tension entre une électrode de mesure (1, 2) et une électrode de référence (3) ou par mesure de la tension entre deux électrodes de mesure [(1) et (2)]. On peut améliorer la sélectivité vis-à-vis des constituants individuels du gaz à mesurer en sélectionnant les matériaux des électrodes de mesure, notamment en utilisant des semi-conducteurs. En utilisant un électrolyte solide poreux, on peut éviter le recours à une atmosphère gazeuse de référence et accroître ainsi la miniaturisation et simplifier la conception.
EP97923831A 1996-06-12 1997-05-16 Detecteur pour determiner la concentration de constituants oxydables d'un melange gazeux Withdrawn EP0843813A1 (fr)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
DE19623434 1996-06-12
DE19623434A DE19623434A1 (de) 1996-06-12 1996-06-12 Sensor zur Bestimmung der Konzentration oxidierbarer Bestandteile in einem Gasgemisch
PCT/DE1997/000996 WO1997047963A1 (fr) 1996-06-12 1997-05-16 Detecteur pour determiner la concentration de constituants oxydables d'un melange gazeux

Publications (1)

Publication Number Publication Date
EP0843813A1 true EP0843813A1 (fr) 1998-05-27

Family

ID=7796739

Family Applications (1)

Application Number Title Priority Date Filing Date
EP97923831A Withdrawn EP0843813A1 (fr) 1996-06-12 1997-05-16 Detecteur pour determiner la concentration de constituants oxydables d'un melange gazeux

Country Status (7)

Country Link
US (1) US6022464A (fr)
EP (1) EP0843813A1 (fr)
JP (1) JP4162262B2 (fr)
KR (1) KR19990036337A (fr)
CN (1) CN1195403A (fr)
DE (1) DE19623434A1 (fr)
WO (1) WO1997047963A1 (fr)

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19623212A1 (de) * 1996-06-11 1997-12-18 Bosch Gmbh Robert Sensor zur Bestimmung der Konzentration oxidierbarer Bestandteile in einem Gasgemisch
DE19846487C5 (de) 1998-10-09 2004-12-30 Basf Ag Meßsonde für die Detektion der Momentankonzentrationen mehrerer Gasbestandteile eines Gases
DE19932048A1 (de) * 1999-07-09 2001-01-11 Bosch Gmbh Robert Meßfühler zur Bestimmung einer Konzentration von Gaskomponenten in Gasgemischen
DE19944181A1 (de) 1999-09-15 2001-04-12 Bosch Gmbh Robert Sensor zur Bestimmung der Konzentration von Gaskomponenten in Gasgemischen
US6849239B2 (en) * 2000-10-16 2005-02-01 E. I. Du Pont De Nemours And Company Method and apparatus for analyzing mixtures of gases
FR2819314B1 (fr) * 2001-01-08 2003-06-13 Alstom Procede pour controler de facon non intrusive un taux de melange d'un melange gazeux a au moins deux composants
DE10310953B4 (de) * 2003-03-13 2006-03-09 Robert Bosch Gmbh Unbeheiztes, planares Sensorelement zur Bestimmung der Konzentration einer Gaskomponente in einem Gasgemisch
JP2006126056A (ja) * 2004-10-29 2006-05-18 Tdk Corp 二酸化炭素センサ
DE102005015569A1 (de) * 2005-04-05 2006-10-12 Robert Bosch Gmbh Keramisches Widerstands- oder Sensorelement
US20080110769A1 (en) * 2006-11-09 2008-05-15 Delphi Technologies Inc. Exhaust gas sensors and methods for measuring concentrations of nox and ammonia and temperatures of the sensors
CA2717032A1 (fr) * 2008-02-28 2009-09-03 Nextech Materials, Ltd. Cellules electrochimiques amperometriques et capteurs
JP4996527B2 (ja) * 2008-04-14 2012-08-08 日本特殊陶業株式会社 積層型ガスセンサ素子及びガスセンサ
US8399883B2 (en) 2008-09-30 2013-03-19 Iljin Copper Foil Co., Ltd. Nitrogen-oxide gas sensor with long signal stability
WO2010038989A2 (fr) * 2008-09-30 2010-04-08 일진소재산업(주) Capteur de gaz d'oxyde d'azote
US8974657B2 (en) 2010-09-03 2015-03-10 Nextech Materials Ltd. Amperometric electrochemical cells and sensors
CH705070B1 (fr) * 2011-07-15 2022-01-14 Swatch Group Res & Dev Ltd Capteur d'hydrogène à couche active et procédé de fabrication de capteurs d'hydrogène.
KR102168091B1 (ko) 2012-03-08 2020-10-20 넥스테크 머티리얼스, 엘티디. 전류계 전기화학 센서, 센서 시스템 및 검출 방법
CN104374818A (zh) * 2014-08-08 2015-02-25 杭州纳瑙新材料科技有限公司 一种平面型氧传感器
KR101769303B1 (ko) * 2016-06-14 2017-08-18 현대자동차주식회사 고체전해질용 co2 센서 및 이의 제조방법

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Also Published As

Publication number Publication date
JPH11510908A (ja) 1999-09-21
US6022464A (en) 2000-02-08
KR19990036337A (ko) 1999-05-25
WO1997047963A1 (fr) 1997-12-18
CN1195403A (zh) 1998-10-07
JP4162262B2 (ja) 2008-10-08
DE19623434A1 (de) 1997-12-18

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