[go: up one dir, main page]
More Web Proxy on the site http://driver.im/

WO2008058553A1 - Détecteur de gaz et poudre d'oxyde métallique sensible aux gaz - Google Patents

Détecteur de gaz et poudre d'oxyde métallique sensible aux gaz Download PDF

Info

Publication number
WO2008058553A1
WO2008058553A1 PCT/EP2006/010892 EP2006010892W WO2008058553A1 WO 2008058553 A1 WO2008058553 A1 WO 2008058553A1 EP 2006010892 W EP2006010892 W EP 2006010892W WO 2008058553 A1 WO2008058553 A1 WO 2008058553A1
Authority
WO
WIPO (PCT)
Prior art keywords
gas
metal oxide
gas sensor
sensitive
oxide powder
Prior art date
Application number
PCT/EP2006/010892
Other languages
English (en)
Inventor
Luca Marinotto
Agustin Sin Xicola
Beatrice Vendemiati
Silvia Ardizzone
Giuseppe Cappelletti
Original Assignee
Pirelli & C. S.P.A.
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 Pirelli & C. S.P.A. filed Critical Pirelli & C. S.P.A.
Priority to PCT/EP2006/010892 priority Critical patent/WO2008058553A1/fr
Publication of WO2008058553A1 publication Critical patent/WO2008058553A1/fr

Links

Classifications

    • 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
    • G01N27/125—Composition of the body, e.g. the composition of its sensitive layer

Definitions

  • the present invention relates to a gas sensor, to a gas-sensitive metal oxide powder, to a method for producing said gas-sensitive metal oxide powder, as well as to an use of said gas sensor for detecting the presence of gases.
  • Sensors are utilized in a variety of applications to determine the presence of gases, e.g. reducing gases such as hydrogen, carbon monoxide, ammonia, methane, alcohols.
  • gases e.g. reducing gases such as hydrogen, carbon monoxide, ammonia, methane, alcohols.
  • ammonia sensors are being used in several applications such as food technology, chemical plants, medical diagnosis, and environmental protection.
  • the threshold limit values (TLVs) for NO2 gas and NO gas is 3 ppm and 25 ppm, respectively (see, for example, N. O. Korolkoff, "Solid State Technology", 32 (1989), pg. 49-64).
  • an NO x sensor is required to have a high sensitivity that can correspond to such low threshold limit values (TLVs).
  • Tungsten trioxide (WO 3 ) is considered to be one of the best candidates among NO ⁇ -sensing materials (see, for example, M. Akiyama et al., "Chemical Letters” (1991), pg. 1611-1614).
  • gas sensors comprise a gas-sensitive portion, usually in the form of a film, in conjunction with a substrate and electrodes, the chemical/electrical responses of said gas-sensitive portion being subjected to changes by adsorption, desorption of a gas, or the like. Measurements of said chemical/electrical responses provide the concentration of the gas.
  • a gas-sensitive portion usually in the form of a film
  • the chemical/electrical responses of said gas-sensitive portion being subjected to changes by adsorption, desorption of a gas, or the like. Measurements of said chemical/electrical responses provide the concentration of the gas.
  • C. Cantalini et al., "Sensors and Actuators", B 31 (1996), pg. 81-87 disclose a thin film (i.e. thickness lower than 3 ⁇ m) of tungsten trioxide (WO 3 ) prepared by high vacuum thermal evaporation from tungsten trioxide (WO 3 ) powder and thermal annealing. Said thin film is said to show
  • US Patent 7,017,389 discloses a sensor for detecting gases including a substrate, electrodes and a thin film metal oxide.
  • a method for selecting the metal oxide to be utilized in the sensors which are highly selective for a specific gas, and a method for determining the presence of a specific gas in a gaseous mixture, are also provided.
  • the abovementioned sensor is said to be useful in any environment or for any application where the detection of a specific gas, e.g., ammonia or nitrogen dioxide, is required.
  • said sensor is said to be useful in both the qualification and quantification of a specific gas in a gaseous mixture sample.
  • said sensor is said to be especially beneficial for use in automotive processes, such as those involving SCR, and biosensors.
  • the Applicant has noticed that the gas sensors above disclosed may not have a good sensitivity for the gas to be detected, in particular when low gas concentrations such as, for example, lower than or equal to 5 ppm, has to be detected.
  • the Applicant has noticed that the gas sensors above disclosed may not be able to maintain a good sensitivity when working at high temperatures such as, for example, at temperatures higher than 250 0 C. Furthermore, the Applicant has noticed that, in the case of a thin film such as, for example, of a film having a thickness lower than or equal to 3 ⁇ m, the life-time of the gas sensors may be remarkably reduced.
  • the Applicant has faced the problem of providing a gas sensor having a good sensitivity to low gas concentrations (i.e. gas concentrations lower than or equal to 5 ppm), both when working at low temperatures (i.e. at temperatures of from 100 0 C to 25O 0 C) and at high temperatures (i.e. at temperatures higher than 250 0 C).
  • low temperatures i.e. at temperatures of from 100 0 C to 25O 0 C
  • high temperatures i.e. at temperatures higher than 250 0 C.
  • a gas sensor comprising a gas- sensitive portion having a high total pore volume (V t ) (i.e. a total pore volume higher than 0.010 mL/g) is endowed with good sensing properties, namely it is able to detect gases at low concentrations (i.e. lower than or equal to 5 ppm), both when working at low temperatures (i.e. at temperatures of from 100 0 C to 25O 0 C) and at high temperatures (i.e. at temperatures higher than 250 0 C).
  • said gas-sensor shows improved sensing properties when working at low temperatures (i.e. at temperatures of from 100 0 C to 250 0 C).
  • said gas-sensor shows an improved life-time.
  • the present invention relates to a gas sensor comprising a substrate, at least one detector electrode, a gas-sensitive portion comprising at least one metal oxide, said gas-sensitive portion being in contact with said at least one detector electrode, characterized in that said gas-sensitive portion has a total pore volume (V t ) higher than 0.010 ml_/g.
  • the substrate of the gas sensors of the present invention may be any material suitable for use in a gas sensor, such as Si/SiO 2 , SiC, GaN, AI 2 O 3 , or mixtures thereof.
  • the substrate comprises aluminium oxide.
  • the gas sensors of the present invention is provided with at least one detector electrode placed between the substrate and in communication with the gas-sensitive portion, and the gas-sensitive portion may be arranged so as to be capable of being contacted with a gas or gaseous mixture to be detected.
  • Said detector electrode may be made of any material suitable for use in sensors, such as gold, silver, tungsten, chromium, titanium, or mixtures thereof.
  • a gold detector electrode is used in the gas sensors of the present invention.
  • said at least one metal oxide may be selected, for example, from: tungsten trioxide (WO 3 ), titanium dioxide (TiO 2 ), molybdenum trioxide (MoO 3 ), vanadium pentoxide (V 2 Os), zirconium dioxide (ZrO 2 ), niobium pentoxide (Nb 2 O 5 ), iridium dioxide (Ir 2 O 2 ), tantalum dioxide (Ta 2 O 3 ), perovskite compounds selected from the group of LaFeO 3 , SmFeO 3 , or mixtures thereof.
  • Tungsten trioxide (WO 3 ) is particularly preferred.
  • the gas sensors of the present invention are resistive gas detectors that rapidly detect, within seconds, low concentrations (i.e. lower than or equal to 5 ppm) of specific gases with reduced interference from other gases, both when working at low temperatures (i.e. at temperatures of from 10O 0 C to 25O 0 C) and at high temperatures (i.e. at temperatures higher than 25O 0 C).
  • low temperatures i.e. at temperatures of from 10O 0 C to 25O 0 C
  • high temperatures i.e. at temperatures higher than 25O 0 C.
  • the gas sensor according to the presence invention may be configured to detect the presence of various gases as well as of their vapours.
  • Gases and their vapours which may be detected by the gas sensors in accordance with the present invention may be nitrogen-lacking reducing gases, such as hydrogen, carbon monoxide, alcohols (such as ethanol), hydrocarbons (such as methane and propylene); nitrogen-containing reducing gases, such as ammonia and amines, and oxidizing gases, such as oxygen, nitrogen monoxide, nitrogen dioxide, and the like.
  • the gas which may be detected by the gas sensors in accordance with the present invention is nitrogen monoxide (NO), or nitrogen dioxide (NO2).
  • Said gas-sensitive portion is capable of exhibiting a response in the form of an increase or a decrease in its electrical property in the presence of the selected gas, while exhibiting little or no response to other gases present in the gaseous mixture sample.
  • said gas-sensitive portion is in the form of a film having a thickness of from 5 ⁇ m to 100 ⁇ m, more preferably of from 10 ⁇ m to 70 ⁇ m, still more preferably of from 20 ⁇ m to 50 ⁇ m.
  • said gas-sensitive portion has a total pore volume (V t ) higher than 0.020 mL/g, more preferably higher than 0.030 ml_/g, still more preferably higher than 0.040 mL/g.
  • said gas-sensitive portion has a specific surface area (S BET ) higher than 2.0 m 2 /g, more preferably higher than 3.0 m 2 /g, still more preferably higher than 4.0 m 2 /g. Gas sensors having higher specific surface area show a still better sensitivity.
  • the metal oxide powder according to the present description and claims is substantially pure.
  • substantially pure means that the metal oxide powder lacks any dopant.
  • the metal oxide powder included in the gas-sensitive portion of the gas sensor according to the present invention is advantageously prepared via a sol-gel process.
  • the present invention relates to a process for producing a gas-sensitive metal oxide powder, said process comprising the steps of: a) dissolving a metal oxide precursor in at least one organic solvent in the presence of at least one surfactant; b) hydrolyzing the dissolved precursor by adding water so as to obtain a metal oxide hydrate gel; c) drying the obtained metal oxide hydrate gel so as to obtain a xerogel; and d) thermally treating the obtained xerogel so as to obtain a gas-sensitive metal oxide powder; wherein in the above step a), said at least one surfactant is present in a molar concentration of from 0.5*10 "6 M to 5*10 "4 M, preferably of from 1*10 "6 M to 3*10 " * M and the surfactant/metal oxide precursor are present in a molar ratio of from 1MO -6 M to 6*10 " * M, preferably of from 4*10 '6 M to 5 4 IO "4 M.
  • said at least one surfactant may be selected from cationic surfactants such as, for example, cetylpyridinium chloride (C 2 i H 3 SNCI), cethyltrimethylammonium chloride [CH 3 (CH 2 ) IS N(CH S ) 3 CI], cethyltrimethylammonium bromide [CH 3 (CH 2 )i 5 N(CH 3 ) 3 Br], or mixtures thereof. Cetylpyridinium chloride (C21H 38 NCI) is particularly preferred.
  • the gas-sensitive metal oxide powder obtained with the above described process is a tungsten trioxide (WO 3 ) powder.
  • the metal oxide precursors useful in said dissolving step a) may be selected, for example, from metallorganic precursors such as, for example, metal esters, metal alkoxides, or mixtures thereof; or from inorganic precursors such as, for example, metal nitrates, metal halides, or mixtures thereof.
  • the metal oxide precursor may be selected from metal halides such as, for example metal chloride or metal bromide. Metal chloride is particularly preferred .
  • metal oxide precursors such as, for example, metal halides
  • the resulting anions should be removed from the solution, for example by repeated washings, because their presence in the final product could increase the resistivity thereof and decrease the gas sensor sensitivity.
  • the organic solvent useful in said dissolving step a) may be selected, for example, from alcohols such as, for example, ethanol, propanol, butanol, or mixture thereof. Ethanol is particularly preferred.
  • said dissolving step a) is carried out by keeping the metal oxide precursor and the surfactant under stirring, in the organic solvent, for a time sufficient to the salt to dissolve.
  • they are kept under stirring at a speed rate of from 100 r.p.m. to 400 r.p.m., more preferably of from 150 r.p.m. to 300 r.p.m., at a temperature of from 1O 0 C to 30 0 C, more preferably of from 15 0 C to 25 0 C, for a time of from 1 min to 100 min, more preferably of from 5 min to 30 min.
  • said hydrolizing step b) is carried out by slowly adding the water to the mixed solution obtained at the end of the dissolving step a), in the amount requested by the stoichiometry of the reaction.
  • the obtained metal oxide hydrate gel is still kept under stirring at a speed rate of from 100 r.p.m. to 400 r.p.m., more preferably of from 150 r.p.m.
  • said drying step c) is carried out by heating the obtained metal oxide hydrate gel at a temperature of from
  • the obtained xerogel product may be pulverized in a mortar to obtain a xerogel powder.
  • said thermally treating step d) is carried out by thermally treating the obtained xerogel at a temperature of from 400°C to 1100 0 C, more preferably of from 55O 0 C to 800°C, for a time of from 1 hour to 6 hours, more preferably of from 2 hours to 5 hours.
  • said thermally treating step d) is carried out in the presence of oxygen current.
  • oxygen current By this way, the thermal decomposition of the surfactant and the removal of traces of solvent and of crystallization water is greatly improved.
  • both an improved oxidation of the metal and a crystalline structure of the gas-sensitive metal oxide powder is obtained.
  • the obtained gas-sensitive metal oxide powder is cooled to room temperature (23 0 C).
  • Said cooling may be carried out in air or, preferably, by furnace cooling, applying a cooling rate of 20°C/min to 50°C/min, preferably of from 30°C/min to 40°C/min.
  • the process of the present invention for producing a gas-sensitive metal oxide powder provides very good yields, higher than 90%, preferably higher than 95%.
  • the cited above process allows the preparation of a gas-sensitive metal oxide powder having a high total pore volume, feature which allows an easier passage of the gas to be detected through the powder; thus, it is possible to advantageously provide a gas-sensitive metal oxide powder having a good, and even improved, sensitivity.
  • the present invention relates to a gas-sensitive metal oxide powder having a total pore volume (V t ) higher than 0.075 mUg, more preferably, higher than 0.100 ml_/g, still more preferably higher than 0.120 mUg.
  • said gas-sensitive metal oxide powder has a specific surface area (S BE T) higher than 6.0 m 2 /g, more preferably higher than 7.0 m 2 /g, still more preferably higher than 8.0 m 2 /g.
  • V t total pore volume
  • SBET specific surface area
  • a slurry of the gas-sensitive metal oxide powder obtained as disclosed above may be advantageously prepared.
  • said slurry is prepared by mixing at least one gas-sensitive metal oxide powder obtained as disclosed above with at least one dispersing agent.
  • said mixing is carried out at a temperature of from 10 0 C to 50 0 C, preferably of from 20 0 C to 4O 0 C, for a time of from 10 min to 20 hours, preferably of from 15 min to 5 hours.
  • said slurry further comprises at least one resin.
  • said slurry further comprises at least one glass binder.
  • said at least one dispersing agent may be selected, for example from inert liquids such as, for example, aliphatic alcohols; esters of said alcohols such as, for example, acetates such as, for example, 2- buthoxyethoxyethylacetate; terpenes such as, for example, turpentine, ⁇ - terpineol; or mixtures thereof.
  • inert liquids such as, for example, aliphatic alcohols
  • esters of said alcohols such as, for example, acetates such as, for example, 2- buthoxyethoxyethylacetate
  • terpenes such as, for example, turpentine, ⁇ - terpineol
  • ⁇ -Terpineol, 2-buthoxyethoxyethylacetate, or mixtures thereof are particularly preferred.
  • said at least one dispersing agent is present in said slurry in an amount of from 25% to 40% by weight, preferably of from 30% to 35% by weight, with respect to the total weight of the slurry.
  • said at least one resin may be selected, for example, from: cellulose resins such as, for example, methylcellulose, ethylcellulose, or mixtures thereof. Ethylcellulose is particularly preferred.
  • said at least one resin is present in said slurry in an amount of from 1.0% to 4.0% by weight, preferably of from 2.0% to 3.0% by weight, with respect to the total weight of the slurry.
  • said at least one glass binder may be selected, for example, from glass frits, said glass frit comprising at least two metal oxides which may be selected, for example, from: silicon oxides, aluminium oxides, lead oxides, bismuth oxides, boron oxides, phosphate oxides, bismuth oxides, borate oxides. Glass frits comprising a mixture of silicon oxides, aluminum oxides and lead oxides, are particularly preferred.
  • said at least one glass binder is present in said slurry in an amount of from 0.10% to 1.0% by weight, preferably of from 0.15% to 0.30% by weight, with respect to the total weight of the slurry.
  • the gas sensor of the present invention is provided with at least one detector electrode.
  • Said at least one detector electrode may be provided on the gas sensor substrate by any suitable method.
  • said at least one detector electrode may be placed on the surface of the gas sensor substrate and, subsequently, the slurry of metal oxide powder obtained as above reported, may be applied to said at least one detector electrode and said substrate, thereby coating both and adhering said at least one detector electrode to said substrate.
  • Other methods for applying the detector electrode to the substrate include, but are not limited to, lithographic techniques, sputtering, laser processing, photochemical methods, etc.
  • Said slurry may be applied to said at least one detector electrode by methods known to those skilled in the art which include, but are not limited to, screen printing deposition, ion beam deposition, plasma polymerization of appropriate gases, electron beam polymerization of appropriate monomers, chemical or plasma assisted chemical vapour deposition, e-beam, thermal or laser beam evaporation or sputtering of solid dielectric sources, metallic- organic chemical vapour deposition, laser ablation, excimer laser interactions with appropriate gases at the substrate surface. Screen printing deposition is particularly preferred.
  • the obtained layer of slurry is heated at a temperature higher than or equal to 700 0 C, preferably of from 75O 0 C to 85O 0 C, for a time of from 20 min to 5 hours, preferably of from 30 min to 2 hours, in air.
  • the gas sensor of the present invention may further include other means such as, for example, heating means and temperature sensing means.
  • Figure 1 shows a gas sensor 100 comprising six wires for electrical connections 1 , a detection electrode 2, a gas-sensitive portion 3 in contact with the detection electrode 2, a substrate 4, a heating means 5 and an electrically insulating layer 6.
  • the gas-sensitive portion 3 completely covers the detector electrode 2.
  • the gas-sensitive portion 3 may cover only partially the detector electrode 2 (not shown in Figure 1).
  • the sensitivity of a gas sensor is defined by means of the following formula:
  • Ggas/Gcarrier wherein Garner is the conductance of the gas sensor measured in an ambient in which only a reference gas carrier is present, while G gas is the conductance of the same gas sensor measured in the same ambient of above wherein, in addition to the reference gas carrier, the gas to be detected has been introduced.
  • the conductance may be detected by directly measuring, for example, the potential difference at the end portions of the gas sensor.
  • the measurement may be carried out indirectly by incorporating the sensor in a feedback circuit of an oscillator such that the oscillator frequency varies with composition of the gas or gaseous mixture. Gas composition may then be determined using an electronic counter.
  • the signal thus produced may be used to modulate a radio signal and thereby be transmitted over a distance (e.g. by telemetry or as a pulse train along an optical fibre).
  • the reference gas carrier may be, for example, dry air, or air having an amount of relative humidity ranging from 20% to 80%.
  • the measurements are generally carried out at temperatures of from 100 0 C to 700 0 C, preferably of from 200 0 C to 400 0 C.
  • the gas to be detected is nitrogen monoxide (NO) or nitrogen dioxide (NO2).
  • the gas sensor comprises a gas-sensitive portion comprising a tungsten trioxide powder.
  • Sample A1 (invention). The synthesis was carried out using a Pyrex reactor type, provided with one cell for the external circulation of water and placed onto a plate of a magnetic stirrer. 35 ml of a T10 "4 M ethanol solution of cetylpyridinium chloride (C 2 1 H 38 NCI) surfactant, available from Fluka Catalogue Code No. 52349, was added to the reactor and kept under magnetic stirring, at 200 rpm, maintaining the system at the controlled temperature of 20 0 C 1 for 10 min. Then, 3.5 g of tungsten chloride (WCI 6 ) (molar ratio cethylpiridinium chloride and tungsten chloride: 4*10 ⁇ ), available form Aldrich Catalogue Code No.
  • WCI 6 tungsten chloride
  • the xerogel tungsten trioxide was pulverized in an agatha small mortar and subsequently placed within a quartz cell, isolated from the outside, into a tubular oven to be thermally treated at the temperature of 65O 0 C, for 4h, in a oxygen current.
  • the desired temperature has been reached approximately in 15 min, starting from ambient temperature and increasing approximately of 40 0 C each min.
  • the so obtained tungsten trioxide powder A1 showed a clear yellow color.
  • the obtained tungsten trioxide powder was furnace cooled to room temperature (23 0 C) decreasing approximately of 35°C/min. The reaction yield was 97%.
  • the total pore volume (V t ) and the specific surface area (SBET) were calculated from the adsorption isotherms following IUPAC recommendations (Sing et al., "Pure and Applied Chemistry", Vol. 57 (1985), pg. 603-619). The obtained data are the following: total pore volume (V t ): 0.15 mL/g; specific surface area (SBET): 9.63 m 2 /g.
  • Sample B1 (reference).
  • a reference sample of tungsten trioxide powder B1 was prepared according to the same procedure disclosed for preparing invention Sample A1 , with the difference that the synthesis was carried out in the absence of the cetylpyridinium chloride (0 2 1H 38 NCI) surfactant. To this aim, a 2.5 * 10 1 M solution of tungsten chloride WCI ⁇ ) was used.
  • Sample A2 (invention).
  • a tungsten trioxide slurry A2 was prepared by mixing 66.11 g of Sample A1 (as prepared according to the synthesis previously disclosed in Example 1), 27.85 g of ⁇ -terpineol, 3.55 g of 2- buthoxyethoxyethylacetate, 2.27 g of ethylcellulose and 0.22 g of a glass frit having a melting point of about 65O 0 C and the following composition: SiO 2 ZA 2 IO 3 ZPbO 2 .
  • Sample B2 (reference).
  • a reference sample of solid solution of tungsten trioxide B2 was prepared according to the same procedure disclosed for preparing invention Sample A2, with the difference that the Sample A1 has been replaced by Sample B1 , in the same amount.
  • Sample A3 (invention).
  • a gas sensor according to Fig. 1 was made.
  • a gas sensor comprising six wires for electrical connections 1 , a gold detection electrode 2, a gas-sensitive portion 3 including the tungsten trioxide A2 (as prepared according to Example 2) in contact with a detection electrode 2, a substrate 4 of aluminium oxide, an heating mean (5) and an electrically insulating layer (6) was made.
  • Said gas-sensitive portion was made by screen printing deposition of the tungsten trioxide slurry obtained as disclosed in Example 2, and further heating at 75O 0 C, for 1 hour, in air.
  • the obtained gas-sensitive portion had a thickness of 30 ⁇ m.
  • the total pore volume (V t ) and the specific surface area (S B E T ) of the gas-sensitive portion were calculated from the adsorption isotherms following IUPAC recommendations (Sing et al., "Pure and Applied Chemistry", Vol. 57 (1985), pg. 603-619). The obtained data are the following: total pore volume (V t ): 0.042 mUg; specific surface area (SBET): 4.33 m 2 /g.
  • Sample B3 reference gas sensor B3 was prepared according to the same procedure disclosed for preparing invention Sample A3, with the difference that, in the gas-sensitive portion 3, the tungsten trioxide A2 has been replaced by reference Sample B2.
  • Said gas-sensitive portion has a thickness of 30 ⁇ m.
  • the total pore volume (V t ) and the specific surface area (SBET) of the gas-sensitive portion were calculated from the adsorption isotherms following IUPAC recommendations (Sing et al., "Pure and Applied Chemistry", Vol. 57 (1985), pg. 603-619). The obtained data are the following: total pore volume (V t ): 0.004 ml_/g; - specific surface area (SB E T): 1.52 m 2 /g. EXAMPLE 4 Gas detection.
  • Example A3 The gas sensor according to the present invention (Sample A3) and the reference gas sensor (Sample B3) were subjected to a gas detection. To this aim, the gas sensor according to the present invention (Sample A3) and the reference gas sensor (Sample B3) were subjected to a gas detection. To this aim, the gas sensor according to the present invention (Sample A3) and the reference gas sensor (Sample B3) were subjected to a gas detection. To this aim, the gas sensor according to the present invention (Sample A3) and the reference gas sensor (Sample B3) were subjected to a gas detection. To this aim, the gas sensor according to the present invention (Sample A3) and the reference gas sensor (Sample B3) were subjected to a gas detection. To this aim, the gas sensor according to the present invention (Sample A3) and the reference gas sensor (Sample B3) were subjected to a gas detection. To this aim, the gas sensor according to the present invention (Sample A3) and the reference
  • sample B3 the reference gas sensor (Sample B3) and the reference gas sensor (Sample B3) were placed in a testing chamber which was connected to a computer which allows to control: the heating means 5 in order to heat the gas sensor and to maintain the gas sensor to a desired temperature (i.e. 23O 0 C and 330°C); the detection electrode 2 by recording the voltage-drop on a resistor during the gas flowing over the gas sensor (the obtained data were subsequently converted into conductance values and were given in Table 1 and Table 2).
  • a desired temperature i.e. 23O 0 C and 330°C
  • the detection electrode 2 by recording the voltage-drop on a resistor during the gas flowing over the gas sensor (the obtained data were subsequently converted into conductance values and were given in Table 1 and Table 2).
  • the gas sensor according to the present invention (Sample A3) and the reference gas sensor (Sample B3) were placed in a testing chamber in the presence of a dry air carrier, at a temperature of
  • the response of the gas sensors (sensitivity) at the tested gas is defined as G gas to G a ⁇ r ratio, wherein G gas and G a ir are the conductance in an atmosphere containing nitrogen dioxide and air free from nitrogen dioxide, respectively.
  • the gas sensor according to the invention showed to be able to detect nitrogen dioxide with a sensitivity markedly higher, in particular when working at low temperature (i.e. at 23O 0 C), than those provided by the reference samples, whichever was the concentration of gas to be detected and the gas carrier used.

Landscapes

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

Abstract

L'invention concerne un détecteur de gaz comprenant un substrat, au moins une électrode détectrice et une partie sensible aux gaz comprenant au moins un oxyde métallique, ladite partie sensible aux gaz étant en contact avec ladite électrode détectrice et ledit détecteur de gaz étant caractérisé en ce que ladite partie sensible aux gaz possède un volume de pores total (Vt) supérieur à 0,010 mL/g. Le détecteur de gaz de la présente invention est capable de détecter des gaz à des faibles concentrations, c'est-à-dire inférieures ou égales à 5 ppm, tant à basse température (c'est-à-dire à des températures allant de 100 °C à 250 °C) qu'à haute température (c'est-à-dire à des températures supérieures à 250 °C). Le détecteur de l'inventeur offre également une durée de vie améliorée.
PCT/EP2006/010892 2006-11-14 2006-11-14 Détecteur de gaz et poudre d'oxyde métallique sensible aux gaz WO2008058553A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
PCT/EP2006/010892 WO2008058553A1 (fr) 2006-11-14 2006-11-14 Détecteur de gaz et poudre d'oxyde métallique sensible aux gaz

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/EP2006/010892 WO2008058553A1 (fr) 2006-11-14 2006-11-14 Détecteur de gaz et poudre d'oxyde métallique sensible aux gaz

Publications (1)

Publication Number Publication Date
WO2008058553A1 true WO2008058553A1 (fr) 2008-05-22

Family

ID=38353403

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/EP2006/010892 WO2008058553A1 (fr) 2006-11-14 2006-11-14 Détecteur de gaz et poudre d'oxyde métallique sensible aux gaz

Country Status (1)

Country Link
WO (1) WO2008058553A1 (fr)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105259306A (zh) * 2015-10-13 2016-01-20 武汉工程大学 一种纳米过渡金属氧化物敏感浆料及其制备方法和应用
JP2018004573A (ja) * 2016-07-08 2018-01-11 株式会社フジクラ 水素ガスセンサ
DE102019002782A1 (de) * 2019-04-16 2020-10-22 Eberhard-Karls-Universität Tübingen Gassensor und Verfahren zur selektiven Detektion von Acetylen und Ethylen
CN112250113A (zh) * 2020-10-28 2021-01-22 青岛大学 一种碳聚合物点/氧化钨复合气敏材料及其制备方法和应用
CN112630181A (zh) * 2020-12-15 2021-04-09 浙江科技学院 一种紫外光激发的纳米纤维素柔性气敏传感器的制备方法
CN115128134A (zh) * 2022-06-21 2022-09-30 武汉铂纳智感科技有限公司 一种基于光激发的气敏传感器、制备方法及应用
US11513091B2 (en) * 2016-05-27 2022-11-29 Carrier Corporation Gas detection device and method of manufacturing the same
CN116621222A (zh) * 2023-07-24 2023-08-22 南方电网数字电网研究院有限公司 钨钒掺杂铌氧化物的制备方法、钨钒掺杂铌基材料及应用

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1467735A (en) * 1973-08-31 1977-03-23 Ford Motor Co Ceramic gas sensor
JPH09113480A (ja) * 1995-10-13 1997-05-02 Ngk Spark Plug Co Ltd 酸素センサ素子
EP1154263A1 (fr) * 1999-10-27 2001-11-14 Ngk Spark Plug Co., Ltd. Detecteur d'oxygene et procede de fabrication d'un element de detection

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1467735A (en) * 1973-08-31 1977-03-23 Ford Motor Co Ceramic gas sensor
JPH09113480A (ja) * 1995-10-13 1997-05-02 Ngk Spark Plug Co Ltd 酸素センサ素子
EP1154263A1 (fr) * 1999-10-27 2001-11-14 Ngk Spark Plug Co., Ltd. Detecteur d'oxygene et procede de fabrication d'un element de detection

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105259306A (zh) * 2015-10-13 2016-01-20 武汉工程大学 一种纳米过渡金属氧化物敏感浆料及其制备方法和应用
US11513091B2 (en) * 2016-05-27 2022-11-29 Carrier Corporation Gas detection device and method of manufacturing the same
JP2018004573A (ja) * 2016-07-08 2018-01-11 株式会社フジクラ 水素ガスセンサ
DE102019002782A1 (de) * 2019-04-16 2020-10-22 Eberhard-Karls-Universität Tübingen Gassensor und Verfahren zur selektiven Detektion von Acetylen und Ethylen
CN112250113A (zh) * 2020-10-28 2021-01-22 青岛大学 一种碳聚合物点/氧化钨复合气敏材料及其制备方法和应用
CN112250113B (zh) * 2020-10-28 2023-01-10 青岛大学 一种碳聚合物点/氧化钨复合气敏材料及其制备方法和应用
CN112630181A (zh) * 2020-12-15 2021-04-09 浙江科技学院 一种紫外光激发的纳米纤维素柔性气敏传感器的制备方法
CN112630181B (zh) * 2020-12-15 2024-03-22 浙江科技学院 一种紫外光激发的纳米纤维素柔性气敏传感器的制备方法
CN115128134A (zh) * 2022-06-21 2022-09-30 武汉铂纳智感科技有限公司 一种基于光激发的气敏传感器、制备方法及应用
CN116621222A (zh) * 2023-07-24 2023-08-22 南方电网数字电网研究院有限公司 钨钒掺杂铌氧化物的制备方法、钨钒掺杂铌基材料及应用
CN116621222B (zh) * 2023-07-24 2023-12-12 南方电网数字电网研究院有限公司 钨钒掺杂铌氧化物的制备方法、钨钒掺杂铌基材料及应用

Similar Documents

Publication Publication Date Title
WO2008058553A1 (fr) Détecteur de gaz et poudre d'oxyde métallique sensible aux gaz
US6173602B1 (en) Transition metal oxide gas sensor
Carotta et al. Nanostructured pure and Nb-doped TiO2 as thick film gas sensors for environmental monitoring
US20030217586A1 (en) Sensors including metal oxides selective for specific gases and methods for preparing same
US6134946A (en) Nano-crystalline porous tin oxide film for carbon monoxide sensing
Biskupski et al. Nanosized titania derived from a novel sol–gel process for ammonia gas sensor applications
Ashraf et al. Aerosol assisted chemical vapour deposition of WO 3 thin films from tungsten hexacarbonyl and their gas sensing properties
Güntner et al. Flame-made chemoresistive gas sensors and devices
EP1923697A1 (fr) Capteur de gaz hautement sensible et son procédé de fabrication
US6843900B2 (en) Potentiometric NOx sensors based on yttria-stabilized zirconia with zeolite modified electrode
JP3054850B2 (ja) 湿度検知方法
US6881582B2 (en) Thin film ethanol sensor and a process for the preparation
Wilson et al. Sol-gel materials for gas-sensing applications
Cantalini et al. Investigation on the cross sensitivity of NO2 sensors based on In2O3 thin films prepared by sol-gel and vacuum thermal evaporation
Ravikumar et al. Gas sensing nature and characterization of Zr doped TiO2 films prepared by automated nebulizer spray pyrolysis technique
AU2002216358A1 (en) Thin film ethanol sensor and a process for the preparation
EP2000797A1 (fr) Matériel, microcapteur comportant un matériel, utilisation du microcapteur, et processus de fabrication du matériel
JP4805146B2 (ja) 二酸化炭素（ｃｏ２）センサーに用いるための混合金属酸化物の製造方法
Gopala Krishnan et al. A study of the physical properties and gas‐sensing performance of TiO2 nanofilms: Automated nebulizer spray pyrolysis method (ANSP)
Tripathy et al. Carbon monoxide sensitivity of tin oxide thin film synthesized by sol gel method
Chakraborty et al. Material surface--analyte interactions with similar energy rates vary as univariate quadratic function of topological polar surface area of analytes
JPH085591A (ja) ガスセンサ及びその製造方法
Della Gaspera et al. Sol–gel for gas sensing applications
Davis et al. Flammable gas sensors based on sol-gel materials
KR20240140623A (ko) 고감도 이소프렌 가스 감응층, 가스센서 및 가스 센서의 제조 방법

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 06818515

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 06818515

Country of ref document: EP

Kind code of ref document: A1