WO2008097184A1 - Réglage de la mobilité ionique dans des matières contenant de l'oxyde de cérium - Google Patents

Réglage de la mobilité ionique dans des matières contenant de l'oxyde de cérium Download PDF

Info

Publication number
WO2008097184A1
WO2008097184A1 PCT/SE2008/050136 SE2008050136W WO2008097184A1 WO 2008097184 A1 WO2008097184 A1 WO 2008097184A1 SE 2008050136 W SE2008050136 W SE 2008050136W WO 2008097184 A1 WO2008097184 A1 WO 2008097184A1
Authority
WO
WIPO (PCT)
Prior art keywords
volume
ceria
field
oxygen
oxygen storage
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/SE2008/050136
Other languages
English (en)
Inventor
Natalia V. Skorodumova
Sergei I. Simak
Börje Johansson
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.)
Individual
Original Assignee
Individual
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 Individual filed Critical Individual
Publication of WO2008097184A1 publication Critical patent/WO2008097184A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/10—Fuel cells with solid electrolytes
    • H01M8/12—Fuel cells with solid electrolytes operating at high temperature, e.g. with stabilised ZrO2 electrolyte
    • H01M8/124—Fuel cells with solid electrolytes operating at high temperature, e.g. with stabilised ZrO2 electrolyte characterised by the process of manufacturing or by the material of the electrolyte
    • H01M8/1246—Fuel cells with solid electrolytes operating at high temperature, e.g. with stabilised ZrO2 electrolyte characterised by the process of manufacturing or by the material of the electrolyte the electrolyte consisting of oxides
    • H01M8/126—Fuel cells with solid electrolytes operating at high temperature, e.g. with stabilised ZrO2 electrolyte characterised by the process of manufacturing or by the material of the electrolyte the electrolyte consisting of oxides the electrolyte containing cerium oxide
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/34—Chemical or biological purification of waste gases
    • B01D53/92—Chemical or biological purification of waste gases of engine exhaust gases
    • B01D53/94—Chemical or biological purification of waste gases of engine exhaust gases by catalytic processes
    • B01D53/9445—Simultaneously removing carbon monoxide, hydrocarbons or nitrogen oxides making use of three-way catalysts [TWC] or four-way-catalysts [FWC]
    • B01D53/945—Simultaneously removing carbon monoxide, hydrocarbons or nitrogen oxides making use of three-way catalysts [TWC] or four-way-catalysts [FWC] characterised by a specific catalyst
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
    • B01J23/10—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of rare earths
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
    • B01J23/38—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals
    • B01J23/54—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals combined with metals, oxides or hydroxides provided for in groups B01J23/02 - B01J23/36
    • B01J23/56—Platinum group metals
    • B01J23/63—Platinum group metals with rare earths or actinides
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J35/00—Catalysts, in general, characterised by their form or physical properties
    • B01J35/30—Catalysts, in general, characterised by their form or physical properties characterised by their physical properties
    • B01J35/33—Electric or magnetic properties
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2255/00—Catalysts
    • B01D2255/20—Metals or compounds thereof
    • B01D2255/206—Rare earth metals
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2255/00—Catalysts
    • B01D2255/90—Physical characteristics of catalysts
    • B01D2255/908—O2-storage component incorporated in the catalyst
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL-COMBUSTION ENGINES
    • F01N2510/00—Surface coverings
    • F01N2510/06—Surface coverings for exhaust purification, e.g. catalytic reaction
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/86—Inert electrodes with catalytic activity, e.g. for fuel cells
    • H01M4/90—Selection of catalytic material
    • H01M4/9016—Oxides, hydroxides or oxygenated metallic salts
    • H01M4/9025—Oxides specially used in fuel cell operating at high temperature, e.g. SOFC
    • H01M4/9033—Complex oxides, optionally doped, of the type M1MeO3, M1 being an alkaline earth metal or a rare earth, Me being a metal, e.g. perovskites
    • 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
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/30—Hydrogen technology
    • Y02E60/50—Fuel cells
    • 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
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
    • Y02P70/50—Manufacturing or production processes characterised by the final manufactured product
    • 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
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/10—Internal combustion engine [ICE] based vehicles
    • Y02T10/12—Improving ICE efficiencies

Definitions

  • the present invention relates in general to devices and methods utilising ceria-containing material, and in particular to devices utilising and methods related to ion mobility in ceria-containing materials.
  • Oxides with the cubic fluorite structure e.g. ceria (CeCh) are known to be good ionic conductors, especially when they are doped with cations of lower valence than the host cations. In these oxides oxygen ions are transported by oxygen vacancies and, therefore, appropriate doping leads to the appearance of an optimal number of vacancies able to support oxygen transport through the oxide.
  • ceria is widely used as an oxygen storage, where its ability to easily take up and release oxygen, depending on oxygen pressure and temperature, is utilized. Under oxygen lean conditions ceria releases oxygen securing CO and NO x conversion whereas in oxygen rich atmosphere ceria readily oxidizes.
  • oxygen storage capacity has mostly been improved by optimizing the composition of ceria-containing materials as an appropriate doping increases the amount of mobile oxygen vacancies.
  • Some examples of such materials presently used in applications are Ce(Zr)Ch, Ce(Sm,Gd)02-x
  • An object of the present invention is to provide oxygen storage devices and methods presenting easily tuneable ion mobility.
  • a further object of the present invention is to provide in-situ restoring of oxygen storage devices.
  • an oxygen storage comprises a volume of a ceria-containing material, and means for applying an external field over said volume.
  • the external field comprises preferably an electric field, but may also comprise a magnetic field.
  • the electric field has preferably a field strength giving a potential difference of at least 1 V over the ceria-containing material volume.
  • the oxygen storage is advantageously comprised in a catalyst device, an oxygen sensor, or a fuel cell.
  • a method of tuning ion mobility in a volume of a ceria- containing material comprises the step of applying an external field over the volume.
  • the tuning of ion mobility according to the second aspect can further be utilised in a method of restoring a volume of a ceria- containing material from contamination.
  • One advantage with the present invention is that ion mobility in ceria- containing materials is easily tuneable, providing operational advantages for the arrangements in which the ceria-containing materials are comprised.
  • FIG. 1 is a diagram illustrating calculated electron bands of ceria
  • FIG. 2 is a plot of the electron density difference between ceria with and without applied external field
  • FIG. 3 a diagram illustrating calculated electron bands of ceria when an external field is applied
  • FIG. 4 is a diagram illustrating calculated electron bands of partially reduced ceria
  • FIG. 5 illustrates schematically an embodiment of a catalyst device
  • FIG. 6 is a diagram illustrating conversion rates of different exhaust constituent depending on air- fuel ratio
  • FIG. 7 illustrates schematically an embodiment of a catalyst device according to the present invention
  • FIG. 8 is a flow diagram of steps of an embodiment of a method according to the present invention
  • FIG. 9 is a flow diagram of steps of another embodiment of a method according to the present invention.
  • FIG. 10 illustrates a possible course of events of temperature and applied external field in a catalyst device provided with an oxygen storage device according to the present invention;
  • FIG. 1 1 is a flow diagram of steps of an embodiment of another method according to the present invention.
  • FIG. 12 illustrates schematically an embodiment of an oxygen sensor according to the present invention.
  • FIG. 13 illustrates schematically an embodiment of a fuel cell according to the present invention.
  • the oxygen storage capacity (OSC) of ceria originates from its ability to undergo reversible transformations between two different oxidation states of different stoichiometries. In its most oxidized state, ceria adopts the stable form CeU2. When exposed to an oxygen depleted environment, Ce ⁇ 2 readily releases oxygen, eventually transforming to its most reduced, oxygen poor form Ce2U3. Such behaviour becomes possible due to the ability of cerium atoms to instantly and drastically adjust their electronic configuration to adapt to their local environment. In fact the process of oxygen release leading to oxygen vacancy formation in the oxide is coupled to the electronic localization/ derealization transition of cerium 4f electrons [I].
  • Cerium oxide is an ionic compound where the cerium atoms contribute with four electrons (including f-electrons) to the p-orbitals of oxygen. Results of a theoretical calculation of electron bands 103 of ceria are illustrated in Fig. 1.
  • this effect can according to the present invention be achieved by a forced electron localization onto the f-orbitals 105 of Ce.
  • First-principles calculations performed, using a full-potential LMTO method, have proven that this can be done by an application of an external field, magnetic or electric.
  • Fig. 2 a plot of the electron density difference between Ce ⁇ 2 with and without applied magnetic field is shown. Areas of charge depletion 106 are illustrated with hatchings from upper right to lower left. Areas of charge accumulation 107 are illustrated with hatchings from upper left to lower right.
  • Fig. 5 illustrates schematically a typical catalyst device 10.
  • Exhaust gas 1 typically comprising hazardous gases, such as hydrocarbons, CO and NO x , enters the catalyst device 10 and flows through a reaction structure 12.
  • the actual catalytic reaction takes place at the surface of the reaction structure 12, and harmless gases, such as H2O, CO2 and N2, leave the catalyst through an output 13.
  • the reaction structure 12 is illustrated in a magnified portion revealing the open large- area monolithic structure of a support 14.
  • the support 14 is typically made from metallic material, e.g. stainless steel, or from ceramic material, e.g. cordierite.
  • the support provides a multitude of small channels 15. A typical diameter of the channels is 1 mm.
  • a part of the support 14 is magnified even more in Fig. 5. There, it is seen that the support 14 is covered with a coating
  • the coating 16 is typically a porous oxide, e.g. AI2O3, having a large surface.
  • a typical thickness of the coating is 40 micrometer and the surface area is typically 100 m 2 /g.
  • the active catalyst material 20 can e.g. be Pt metal and is provided in small volumes distributed over the coating surface.
  • Fig. 6 is a diagram the conversion rate of the different constituent, NO x 121, CO 122 and HC 123, depending on the air-fuel ratio.
  • the catalyst can be designed to give an optimum conversion rate at the steady-state exhaust temperature.
  • the temperature determines basically the kinetics of diffusion in the catalyst and operation at non-optimized temperatures gives typically a non-optimum conversion rate.
  • Ceria is used in the three-way catalyst as a promoter for the catalytic reaction.
  • the basic operation of ceria is to function as an oxygen storage capacity.
  • the oxygen storage capacity operates by storing excess oxygen under oxidizing, or lean, conditions, whereas the oxygen storage capacity operates by releasing oxygen under reducing, or rich, conditions.
  • the oxygen storage and releasing capacity is strongly controlled by the ion mobility of the ceria.
  • the temperature of the catalyst is low and the oxygen storage capacity is low. A non-optimum conversion is achieved.
  • ion mobility in oxygen storage devices comprising ceria can be controlled by other means than temperature. This makes it possible to increase the ion mobility under e.g. cold start conditions and thereby compensating the low temperature. When the temperature increases towards normal operation temperature, the ion mobility can successively be adapted to be substantially optimum at all temperatures.
  • Fig. 7 illustrates a three-way catalyst using an oxygen storage 17 with tuneable ion mobility according to the present invention. Two electrodes are provided around the support 14. A negative electrode 24 is placed in connection with the support 14, and a positive electrode 26 is placed above the volume 21 of a ceria-containing material. In alternative embodiments, one or both of the electrodes 24, 26 may be provided without electrical contact to the volume 21.
  • the volume 21 of ceria-containing material operates as an oxygen storage 17 of the catalyst device.
  • an external field 28 is applied over the volume 21.
  • a voltage supply 30 connected to the electrodes 24, 26 constitutes in the present embodiment together with the electrodes 24, 26 the means 31 for applying an external field, and is preferably controllable, to provide variations of the strength of the external field, e.g. depending on the present operation temperature.
  • a control unit 32 is illustrated in Fig. 7.
  • a sensor 34 is connected to the means 31 for applying an external field.
  • the sensor 34 is arranged to measure conditions of the gas entering and/or leaving the catalyst 10.
  • the sensor 34 can typically be a temperature sensor and/or a sensor responsive to gas composition.
  • the output from the sensor 34 is connected to the control unit 32, which is arranged to control the output of the voltage supply 30 in accordance with the sensor output.
  • the catalyst device 10 can thereby be tuned to operate with an optimum oxygen storage capacity at any temperature.
  • FIG. 8 illustrates a flow diagram of steps of an embodiment of a method according to the present invention.
  • the method of tuning ion mobility in a volume of a ceria-containing material begins in step 200.
  • an external field is applied over the volume.
  • the external field comprises preferably an electric field, preferably having a field strength of at least 5 kV/mm over said volume. More preferably, the electric field has a field strength of at Ieast35 kV/mm over the volume.
  • the external field may also comprise a magnetic field.
  • Fig. 9 illustrates another embodiment of a method for tuning the ion mobility according to the present invention.
  • the method of tuning ion mobility in a volume of a ceria-containing material begins in step 200.
  • an external field is applied over the volume.
  • a surrounding temperature or a surrounding gas composition, i.e. surrounding conditions is detected.
  • a strength of the external field is varied in response to a result of the detection in step 230.
  • the procedure ends in step 299.
  • the procedure is here illustrated as a single row of events, however, anyone skilled in the art understands that such controlling of the external field preferably occurs continuously or intermittently. This is indicated by the dotted line 250.
  • Fig. 10 illustrates a possible course of events of temperature and applied external field in a catalyst device provided with an oxygen storage device according to the present invention.
  • the temperature 1 10 is low and thereby the ion mobility of an oxygen storage without external field is low and typically too low for producing an appropriate exhaust conversion at lean operation conditions.
  • the ion mobility can, however, be tuned to a higher level, allowing the catalytic reaction to operate appropriately also at lower temperatures.
  • the exhaust producing process typically is a cyclic procedure, the exhaust conditions vary rapidly between rich conditions and lean conditions. Since the increased ion mobility is needed primarily at the lean conditions, the external field is preferably allowed to vary in registry with the exhaust production cycle, as seen in Fig. 10.
  • the catalyst warms up, as indicated by the temperature curve 110, and the spontaneous ion mobility increases.
  • the maximum applied external field 120 can thereby be reduced in order to provide a suitable amount of oxygen.
  • the external field can be turned off and the catalyst device operates as usual.
  • temperature has been used as indicator for controlling the applied external field.
  • monitoring of the actual result i.e. the gases leaving the catalyst device could be used as an indicator of whether an external field is needed or not.
  • the tuning of ion mobility of the catalyst can also be utilized in order to compensate for changes in incoming exhaust compositions. This can readily be achieved by monitoring the incoming gas composition instead. Such monitoring may then also provide for the periodic variation seen in Fig. 10.
  • ceria In a chamber of a real catalyst ceria is in contact with many different chemicals. Some of them can contaminate the oxygen storage and cause at least partial deactivation. The most damaging contaminants are considered to be phosphorous and sulphur, which cause electron redistribution, delocalizing Ce f-electrons to fill up their own p-shells. This leads to making the neighbouring oxygen vacancies inactive for oxygen transport. Even small concentration of contaminations is able to block the surface layers of ceria- containing materials leading to a noticeable degradation of oxygen storage capacity.
  • Fig. 11 illustrates a flow diagram of steps of an embodiment of a method according to the present invention.
  • the procedure of restoring a volume of a ceria-containing material from contaminations starts in step 260.
  • contamination ion mobility in connection with the volume is tuned. This is performed according to any of the ion mobility tuning methods described here above, and as indicated by the dotted box 220.
  • the application of an external field is able to change the electron distribution in the ceria.
  • An electron redistribution can be forced, moving back the electrons from the contaminants p-shells to become delocalized Ce f-electrons.
  • the contaminants will thereby increase their tendency to leave the ceria, and by applying an appropriate external field, spontaneous emission of contaminants will result.
  • an application of an external field could assist in tuning the oxygen release rates for ceria-containing materials as well as to remove poisoning contaminants.
  • An oxygen storage with tuneable ion mobility can be used also in other applications.
  • a volume of ceria can e.g. be used in oxygen sensor applications.
  • the ceria when ceria is exposed for oxygen- rich atmosphere, the ceria is oxidized to its highest oxidized state CeCb.
  • CeCb When ceria is present in an oxygen-poor atmosphere, a reduction takes place, ate least of the surface of ceria towards Ce2 ⁇ 3.
  • Such oxidation changes are accompanied by changes in electrical properties.
  • Fig. 12 illustrates an embodiment of such an oxygen sensor 50.
  • a volume 21 of a ceria-containing material is provided in contact with a gas volume 51 , in which the oxygen content is to be monitored.
  • the volume 21 of a ceria- containing material thereby acts as an oxygen storage device.
  • a monitor 52 observes electrical properties of the volume 21 of a ceria-containing material.
  • the monitor 52 is in the present embodiment connected to a front electrode 53 provided in contact with the volume 21 at the side facing the gas volume 51.
  • the monitor is further connected to a base electrode 54 provided in contact with a side of the volume 21 opposite to the gas volume 51.
  • the observed electrical property can e.g. be electric conductivity.
  • two external field applying electrodes 24, 26 are provided.
  • the base electrode 54 is also used as one 24 of the field applying electrodes.
  • the other electrode 26 is provided within the gas volume 51.
  • one electrode 26 is provided in electrical contact with the volume 21.
  • both electrodes may be in electrical contact, none of the electrodes 24, 26 may be in electrical contact, or only electrode 26 may be in electrical contact with the volume 21.
  • Fig. 13 illustrates another application of an oxygen storage according to the present invention.
  • An embodiment of a fuel cell 60 is illustrated.
  • a ceria-containing material is used as an oxygen storage device and is provided with an anode 62 at a surface facing a gas volume 67 having a hydrogen rich atmosphere.
  • the basic reaction is:
  • the vacancy in the volume 21 after the oxygen ion is occupied by another oxygen ion, due to diffusion in the volume 21 enabled by a certain ion mobility. Successive replacements of oxygen ions will move 70 the vacancy to the opposite side of the volume 21. This corresponds to a migration of oxygen 64 from the opposite side towards the anode.
  • a cathode 61 is provided at a surface of the volume 21 facing another gas volume 67 instead having an oxygen rich atmosphere. Oxygen molecules dissociate at the surface and oxygen ions are incorporated in the structure of the volume 21 occupying the vacancy originally created at the anode side. This process requires a supply of 2 electrons per oxygen ion:
  • the overall reaction results in formation of water from oxygen and hydrogen and the provision of two excess electrons at the anode and the need of two electrons at the cathode.
  • electrical leads 68, 69 By connecting the anode and the cathode by electrical leads 68, 69, a current will flow from the anode to the cathode. This is the basic operation of a fuel cell. However, in order to have a reasonable ion mobility within the volume 21, the fuel cell has to be operated at very high temperatures.
  • the ion mobility can be increased.
  • two electrodes 24, 26 are provided with a voltage from a voltage supply 30 in order to create the electrical field over the volume 21.
  • none of the electrodes 24, 26 are provided in electrical contact with the volume 21.
  • one or both of the electrodes may be in electrical contact with the volume 21.
  • the increased ion mobility opens up for reduced operation temperatures, and operation temperatures not too much above room temperature may be possible to achieve.
  • HRS and LRS is obtained by the application of a positive and negative threshold voltage of about 3 eV. Oxygen release or ion mobility was, however, not in the focus of this study.
  • the electrodes have been placed within or without direct electric contact with the ceria containing volumes.
  • a gap between the electrodes and the volume may have constructional advantages.
  • an air gap will set higher requirements on the applied voltages in order to reach the requested field strength within the volume.
  • Such considerations have to be made when different applications are designed.
  • the embodiments described above are to be understood as a few illustrative examples of the present invention. It will be understood by those skilled in the art that various modifications, combinations and changes may be made to the embodiments without departing from the scope of the present invention. In particular, different part solutions in the different embodiments can be combined in other configurations, where technically possible. The scope of the present invention is, however, defined by the appended claims.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Materials Engineering (AREA)
  • Organic Chemistry (AREA)
  • Manufacturing & Machinery (AREA)
  • General Chemical & Material Sciences (AREA)
  • Health & Medical Sciences (AREA)
  • Biomedical Technology (AREA)
  • Environmental & Geological Engineering (AREA)
  • Analytical Chemistry (AREA)
  • Oil, Petroleum & Natural Gas (AREA)
  • Combustion & Propulsion (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Sustainable Development (AREA)
  • Sustainable Energy (AREA)
  • Electrochemistry (AREA)
  • Catalysts (AREA)

Abstract

Un stockage d'oxygène (17) comprend un volume (21) de matière contenant de l'oxyde de cérium et des moyens (31) servant à appliquer un champ externe (28) sur le volume (21). Le champ externe (28) induit une mobilité ionique accrue dans le volume (21). Le champ externe (28) est de préférence un champ électrique, mais il peut également être un champ magnétique. Le champ électrique a de préférence une intensité de champ donnant une différence de potentiel d'au moins 1 V sur le volume de matière contenant de l'oxyde de cérium (21). Le stockage d'oxygène (17) est avantageusement inclus dans un dispositif catalyseur (10), un détecteur d'oxygène ou une pile à combustible. De plus, un procédé de réglage de la mobilité ionique dans un volume (21) d'une matière contenant de l'oxyde de cérium comprend l'étape consistant à appliquer un champ externe (28) sur le volume (21). En outre, le réglage de la mobilité ionique peut être également utilisé dans un procédé de régénération d'un volume (21) d'une matière contenant de l'oxyde de cérium après des contaminations.
PCT/SE2008/050136 2007-02-05 2008-02-04 Réglage de la mobilité ionique dans des matières contenant de l'oxyde de cérium Ceased WO2008097184A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
SE0700325-4 2007-02-05
SE0700325 2007-02-05

Publications (1)

Publication Number Publication Date
WO2008097184A1 true WO2008097184A1 (fr) 2008-08-14

Family

ID=39681962

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/SE2008/050136 Ceased WO2008097184A1 (fr) 2007-02-05 2008-02-04 Réglage de la mobilité ionique dans des matières contenant de l'oxyde de cérium

Country Status (1)

Country Link
WO (1) WO2008097184A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2010096957A1 (fr) * 2009-02-25 2010-09-02 中国科学院物理研究所 Procédé d'activation d'un catalyseur à base d'oxyde de terre rare et d'oxyde complexe de celui-ci à l'aide d'un champ électrique

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5604174A (en) * 1994-05-23 1997-02-18 W. R. Grace & Co.-Conn. Metal foil catalyst members by aqueous electrophoretic deposition
US20030094381A1 (en) * 2001-11-20 2003-05-22 Bors Daniel Arthur Electroactive catalysis

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5604174A (en) * 1994-05-23 1997-02-18 W. R. Grace & Co.-Conn. Metal foil catalyst members by aqueous electrophoretic deposition
US20030094381A1 (en) * 2001-11-20 2003-05-22 Bors Daniel Arthur Electroactive catalysis

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
OZAWA M. ET AL.: "In situ X-ray and neutron powder diffraction studies of redox behavior in CeO2-containing oxide catalysts", CATALYSIS TODAY, vol. 50, no. 2, 29 April 1999 (1999-04-29), pages 329 - 342, XP003022055 *

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2010096957A1 (fr) * 2009-02-25 2010-09-02 中国科学院物理研究所 Procédé d'activation d'un catalyseur à base d'oxyde de terre rare et d'oxyde complexe de celui-ci à l'aide d'un champ électrique

Similar Documents

Publication Publication Date Title
KR100538974B1 (ko) 연료전지시스템의 운전방법 및 연료전지시스템
Matsuzaki et al. The poisoning effect of sulfur-containing impurity gas on a SOFC anode: Part I. Dependence on temperature, time, and impurity concentration
Riess The possible use of mixed ionic electronic conductors instead of electrolytes in fuel cells
Riess et al. Solid oxide fuel cells operating on uniform mixtures of fuel and air
Huang et al. A high-performance ceramic fuel cell with samarium doped ceria–carbonate composite electrolyte at low temperatures
Marina et al. A solid oxide fuel cell with a gadolinia-doped ceria anode: preparation and performance
US20030219637A1 (en) Direct hydrocarbon reforming in protonic ceramic fuel cells by electrolyte steam permeation
US10868317B2 (en) Method for starting a fuel cell and fuel cell system
JP2005019041A (ja) 固体電解質層と水素透過性金属膜を用いた電池、燃料電池及びその製造方法
US20030012996A1 (en) Fuel cell
US20050064259A1 (en) Hydrogen diffusion electrode for protonic ceramic fuel cell
Sun et al. Direct electrolysis of CO2 in solid oxide cells supported on ceramic fuel electrodes with straight open pores and coated catalysts
JP2016033863A (ja) 燃料電池システムおよびその運転方法
JP2005093115A (ja) 燃料電池発電装置とその運転方法
Ramanarayanan et al. High temperature ion conducting ceramics
US12297550B2 (en) Chemical and electrochemical cell electronics protection system
US20230290976A1 (en) Chemical and electrochemical cell electronics protection system
WO2008097184A1 (fr) Réglage de la mobilité ionique dans des matières contenant de l'oxyde de cérium
JP2004172106A (ja) 燃料電池システムの運転方法および燃料電池システム
Zhang et al. A-site alkali metal-doped SrTi0. 3Fe0. 7O3-δ: A highly stable symmetrical electrode material for solid oxide electrochemical cells
JP2006283103A (ja) 水蒸気電解セル
JP2005071949A (ja) 燃料電池発電装置とその運転方法
US12126060B2 (en) Chemical and electrochemical cell electronics protection system
JP5605106B2 (ja) 燃料電池発電装置
EP1688516A1 (fr) Electrode pour pile electrochimique et pile electrochimique associee

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: 08712776

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: 08712776

Country of ref document: EP

Kind code of ref document: A1