WO2017213038A1 - Oxide, oxygen storage agent, three-way catalyst for exhaust gas, and method for producing oxide - Google Patents

Oxide, oxygen storage agent, three-way catalyst for exhaust gas, and method for producing oxide Download PDF

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WO2017213038A1
WO2017213038A1 PCT/JP2017/020578 JP2017020578W WO2017213038A1 WO 2017213038 A1 WO2017213038 A1 WO 2017213038A1 JP 2017020578 W JP2017020578 W JP 2017020578W WO 2017213038 A1 WO2017213038 A1 WO 2017213038A1
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oxide
metal
oxygen
osc
sample
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French (fr)
Japanese (ja)
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▲高▼村仁
富田惇喜
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国立大学法人東北大学
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    • 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
    • B01J23/70—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper
    • B01J23/76—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper combined with metals, oxides or hydroxides provided for in groups B01J23/02 - B01J23/36
    • B01J23/84—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper combined with metals, oxides or hydroxides provided for in groups B01J23/02 - B01J23/36 with arsenic, antimony, bismuth, vanadium, niobium, tantalum, polonium, chromium, molybdenum, tungsten, manganese, technetium or rhenium
    • B01J23/889—Manganese, technetium or rhenium
    • B01J23/8892—Manganese
    • 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
    • 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
    • B01J21/00—Catalysts comprising the elements, oxides, or hydroxides of magnesium, boron, aluminium, carbon, silicon, titanium, zirconium, or hafnium
    • B01J21/005—Spinels
    • 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
    • B01J23/70—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper
    • B01J23/76—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper combined with metals, oxides or hydroxides provided for in groups B01J23/02 - B01J23/36
    • B01J23/83—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper combined with metals, oxides or hydroxides provided for in groups B01J23/02 - B01J23/36 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
    • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
    • B01J23/70—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper
    • B01J23/76—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper combined with metals, oxides or hydroxides provided for in groups B01J23/02 - B01J23/36
    • B01J23/84—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper combined with metals, oxides or hydroxides provided for in groups B01J23/02 - B01J23/36 with arsenic, antimony, bismuth, vanadium, niobium, tantalum, polonium, chromium, molybdenum, tungsten, manganese, technetium or rhenium
    • B01J23/889—Manganese, technetium or rhenium
    • 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
    • B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
    • B01J37/04—Mixing
    • 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
    • B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
    • B01J37/08—Heat treatment
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
    • C01G25/00—Compounds of zirconium
    • C01G25/02—Oxides
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
    • C01G49/00—Compounds of iron
    • 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
    • F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
    • F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
    • F01N3/10—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
    • 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
    • F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
    • F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
    • F01N3/10—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
    • F01N3/24—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by constructional aspects of converting apparatus
    • F01N3/28—Construction of catalytic reactors
    • 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 to an oxide, an oxygen storage agent, a three-way catalyst for exhaust gas, and a method for producing an oxide.
  • a three-way catalyst is used to purify exhaust gas from automobiles and the like.
  • the three-way catalyst is a catalyst that simultaneously removes three types of hydrocarbon (HC) carbon monoxide (CO) and nitrogen oxide (NO x ) in the exhaust gas.
  • Pt (platinum), Pd (palladium), Rh (rhodium) or the like used as a catalyst has a narrow air / fuel ratio range in which these three types can be removed simultaneously. Therefore, an oxygen storage agent that stores or releases oxygen when the air-fuel ratio is out of this range is used (for example, Patent Documents 1-3).
  • CeO 2 —ZrO 2 (ceria-zirconia) -based oxides are known as oxygen storage agents. It is known that an oxide composed of gadolinium-added cerium oxide and spinel-type Fe composite oxide is manufactured using the Pecini method (Patent Document 4, Non-Patent Document 1).
  • Oxygen storage capability of CeO 2 -ZrO 2 based oxide (OSC: Oxygen Storage Capacity) characteristic is not sufficient. For example, OSC characteristics deteriorate at a relatively low temperature.
  • the present invention has been made in view of the above problems, and aims to improve OSC characteristics.
  • the present invention includes Ce 1-x Zr x O 2- ⁇ (0 ⁇ x ⁇ 1 and 0 ⁇ ⁇ ) and MFe 2 O 4 having a spinel structure (M is a divalent metal element). It is an oxide.
  • the M may be Mn or Co.
  • the content of the MFe 2 O 4 may be configured to be less than 33% by volume.
  • the oxide is composed of the Ce 1-x Zr x O 2- ⁇ and the MFe 2 O 4, and the content of the MFe 2 O 4 may be 15% by volume or less. .
  • the M may be Co.
  • the present invention provides a crystal of Ce 1-x Zr x O 2- ⁇ containing Ce 1-x Zr x O 2- ⁇ (0 ⁇ x ⁇ 1, 0 ⁇ ⁇ ) and a metal oxide having a spinel structure.
  • An oxide comprising a layer containing the metal oxide at a grain boundary.
  • the layer containing the metal oxide may be an electron conductive layer.
  • the present invention is an oxygen storage agent comprising the above oxide.
  • the present invention is a three-way catalyst for exhaust gas characterized by containing the above oxygen storage agent.
  • the present invention provides a method of producing the Ce 1-x Zr x O 2 - ⁇ (0 ⁇ x ⁇ 1 and 0 ⁇ [delta]) oxide containing a metal oxide having a spinel structure, the Ce 1- forming a complex of the metal from a metal salt constituting x Zr x O 2- ⁇ and the metal oxide, producing a polymer containing the complex, and carbonizing the polymer. It is the manufacturing method of the oxide characterized by including.
  • OSC can be improved.
  • FIG. 1 (a) is a diagram showing a ⁇ at Ce 0.5 Zr 0.5 O 2.
  • FIG. 1 (b) is a diagram schematically showing the reaction during oxygen storage and oxygen release.
  • FIG. 2 is a flowchart showing a method for producing a mixed oxide using the Pechini method.
  • FIG. 3A is a schematic diagram of a mixed oxide produced using the Pecini method.
  • FIG. 3B is a cross-sectional view of the three-way catalyst according to the second embodiment.
  • FIG. 4 is a diagram showing the XRD measurement results of each sample.
  • FIG. 5A is a diagram showing the OSC measurement result of each sample
  • FIG. 5B is a diagram showing ⁇ in each sample.
  • FIG. 6 is a diagram showing the OSC cycle characteristics.
  • FIG. 7A and FIG. 7B are diagrams showing OSC characteristics at 150 ° C.
  • FIG. 8 is a diagram showing OSC with respect to the content of CoFe 2 O 4 .
  • a CeO 2 —ZrO 2 -based oxide used as an oxygen storage agent for a three-way catalyst will be described.
  • the oxygen storage agent releases oxygen when oxygen is insufficient in the three-way catalyst, and stores oxygen when oxygen is excessive. Thereby, even if the air-fuel ratio deviates from the ideal range, three types of hydrocarbons, carbon monoxide and nitrogen oxides in the exhaust gas can be removed simultaneously.
  • CeO 2 —ZrO 2 -based oxide has a high OSC.
  • the Ce 0.5 Zr 0.5 O 2- ⁇ the Ce 0.5 Zr 0.5 O 2- ⁇ .
  • the largest ⁇ is 0.25.
  • Ce 1-x Zr x O 2 has a plurality of phases such as a t ′ phase and a ⁇ phase.
  • t ′ phase or ⁇ phase is mainly used.
  • the t ′ phase is a tetragonal phase.
  • the ⁇ phase is a phase with a pyrochlore-like structure.
  • 1 (a) is a diagram showing a ⁇ at Ce 0.5 Zr 0.5 O 2.
  • ⁇ is ⁇ when oxygen is released.
  • ⁇ is large.
  • the theoretical maximum value ⁇ 0.25 is almost coincident.
  • ⁇ exceeds 0.15.
  • both t ′ phase and ⁇ phase have a very small ⁇ of about 0.01.
  • Ce 1-x Zr x O 2 does not function sufficiently as an oxygen storage agent for relatively low temperature exhaust gas.
  • the exhaust gas temperature is low, and the OSC characteristic of Ce 1-x Zr x O 2 is insufficient.
  • FIG. 1 (b) is a diagram schematically showing the reaction during oxygen storage and oxygen release.
  • oxygen vacancy V O ⁇ and electrons 2e ⁇ are conducted from the inside of the CeO 2 —ZrO 2 oxide to the surface, and oxygen ions O 2 ⁇ is conducted from the surface to the inside.
  • oxygen ions O 2 ⁇ are conducted from the inside of the CeO 2 —ZrO 2 -based oxide to the surface, and oxygen vacancies V 2 O ⁇ and electrons 2e ⁇ are conducted from the surface to the inside.
  • the OSC characteristics of Ce 1-x Zr x O 2 might be limited by the diffusion of electron e ⁇ among the diffusion of oxygen ion O 2 ⁇ and the diffusion of electron e ⁇ .
  • the mixed oxide of Embodiment 1 includes Ce 1-x Zr x O 2- ⁇ and a metal oxide having a spinel structure.
  • the mixed oxide is made of Ce 1-x Zr x O 2- ⁇ and a metal oxide having a spinel structure.
  • a metal oxide having a spinel structure hardly reacts with Ce 1-x Zr x O 2 and has high electron conductivity. For this reason, the conductivity of electrons in the mixed oxide can be increased and the OSC characteristics can be improved.
  • M is a divalent metal element
  • M has high electron conductivity. Therefore, OSC characteristics can be improved by using MFe 2 O 4 for the metal oxide having a spinel structure.
  • M is a transition metal such as Co (cobalt), Mn (manganese), Fe (iron), Cu (copper), Cr (chromium), or Ni (nickel).
  • M may be a Group 2 element such as Mg (magnesium).
  • M may contain a plurality of these elements.
  • a group 1 element such as Li (lithium) is combined with a transition metal such as Fe, and a metal element that is not divalent, such as (Li 0.5 Fe 0.5 ), is combined, and apparently 2 A valent metal element may be used.
  • MFe 2 O 4 may have a stoichiometric composition within a range in which the effect of the embodiment can be obtained. Further, impurities may be included.
  • X in Ce 1-x Zr x O 2- ⁇ may be 0 ⁇ x ⁇ 1.
  • 0.2 ⁇ x ⁇ 0.8 is preferable, 0.3 ⁇ x ⁇ 0.7 is more preferable, and 0.4 ⁇ x ⁇ 0.6 is further preferable. Further, 0 ⁇ ⁇ may be satisfied.
  • Ce 0.5 Zr 0.5 O 2- ⁇ logically 0 ⁇ ⁇ ⁇ 0.25, and when x is close to 0, 0 ⁇ ⁇ ⁇ 0.5.
  • the mixed oxide according to Embodiment 1 can be manufactured using, for example, the Pecini method.
  • FIG. 2 is a flowchart showing a method for producing a mixed oxide using the Pechini method.
  • a metal salt is prepared (step S10).
  • the metal salt is a salt of a metal constituting a metal oxide having a Ce, Zr and spinel structure.
  • the prepared metal salt is a metal salt of Ce, Zr, M, and Fe.
  • metal salts for example, nitrates, sulfates or metal chlorides can be used.
  • a metal complex is generated from the metal salt (step S12).
  • the ligand for example, an organic ligand such as citric acid is used.
  • the ligand is preferably a chelate ligand.
  • a metal complex is generated by dissolving a metal salt in a polyhydric alcohol or the like and adding an excessive chemical substance (for example, citric acid) to be a ligand.
  • a polymer containing a metal complex is generated (step S14).
  • a polymer is produced by heating a solution containing a metal complex and a polymerization initiator.
  • the polymerization initiator is a polyhydric alcohol and the ligand is citric acid
  • an esterification reaction between citric acid and the polyhydric alcohol occurs.
  • a dehydration reaction occurs due to the OH group not reacting with the metal of citric acid and the OH group of the polyhydric alcohol.
  • esters are polymerized and polymerized.
  • the produced polymer is, for example, a gel.
  • the polymer is carbonized (step S16). For example, when a polymerized polymer is heated, a CC chain and / or a CH chain is broken. Thereafter, the carbonized polymer is pulverized. Calcination is performed (step S18). For example, the pulverized powder is calcined at a high temperature. Thereby, a mixed oxide can be produced. In the mixed oxide thus produced, a uniform mixed state of Ce 1-x Zr x O 2- ⁇ and the metal oxide having a spinel structure is maintained.
  • Ce 1-x Zr x O 2 - ⁇ and mixed oxides consisting of spinel-type metal oxide with Pechini method as described in Patent Document 4 and Non-Patent Document 1, Ce 1- the grain at the interface x Zr x O 2- ⁇ believed layer containing a spinel-type metal oxide is formed.
  • FIG. 3A is a schematic diagram of a mixed oxide produced using the Pecini method. As shown in FIG. 3A, there are Ce 1-x Zr x O 2- ⁇ phase crystal grains 12 and spinel-type metal oxide phase crystal grains 14. A layer 16 is formed at the interface of the crystal grains 12. The grain size of the crystal grains 12 and 14 is, for example, several nm to 100 nm. The thickness of the layer 16 is, for example, 1 nm to several tens of nm. The layer 16 includes a spinel metal oxide and functions as an electron conductive layer. The conductivity of electrons in the mixed oxide 10 is increased through the crystal grains 14 and the layer 16. Therefore, OSC characteristics in oxygen storage and oxygen release are improved.
  • the content of one substance phase is required to be 33% by volume or more of the whole.
  • a spinel metal oxide is added to Ce 1-x Zr x O 2- ⁇ , in order to connect the spinel metal oxide phase three-dimensionally so as to contribute to electronic conduction, The content of the spinel-type metal oxide is 33% by volume or more.
  • the spinel type metal oxide is increased, the OSC characteristic per unit weight is lowered.
  • a layer 16 containing a metal oxide having a spinel structure with high electron conductivity is formed at the interface of crystal grains 12 as shown in FIG.
  • the content of the spinel metal oxide is preferably 30% by volume or less, more preferably 25% by volume or less, and further preferably 20% by volume or less.
  • the content of the spinel metal oxide is preferably 1% by volume or more, and more preferably 2% by volume or more.
  • the second embodiment is a three-way catalyst using the mixed oxide of the first embodiment.
  • FIG. 3B is a cross-sectional view of the three-way catalyst according to the second embodiment.
  • an oxygen storage agent 22 is supported on the support material 20.
  • a catalyst metal 24 is supported on the oxygen storage agent 22.
  • the support material 20 is alumina or the like, for example.
  • the oxygen storage agent 22 is the mixed oxide according to the first embodiment.
  • the catalyst metal 24 is a noble metal such as Pt, Pd, or Rh.
  • the oxygen storage agent 22 and the catalyst metal 24 may be supported on the support material.
  • the OSC characteristics of the oxygen storage agent can be improved. For example, the OSC characteristics are improved even at a relatively low temperature.
  • the oxygen storage agent using the mixed oxide of Embodiment 1 as a three-way catalyst for exhaust gas the exhaust gas temperature of a hybrid vehicle or the like can be used as a three-way catalyst.
  • CZ55-MFO and CZ55-CFO were prepared as mixed oxides.
  • the oxide and content of each sample is as follows.
  • CZ55-CFO Ce 0.5 Zr 0.5 O 2 , 15% by volume CoFe 2 O 4
  • step S10 of FIG. 2 the metal salts shown in Table 1 were prepared. Nitrate was used as the salt of Ce, Mn, Co, and Fe, and oxide chloride was used as the salt of Zr. The purity of each metal salt is 99.9 atomic%.
  • the mixing ratio of metal: citric acid: propylene glycol was 1: 3: 3 for Ce, Co, and Fe, and 1: 6: 6 for Zr. Since Mn nitrate Mn (NO 3 ) 2 .6H 2 O has a melting point of 26 ° C., it was directly used as a liquid raw material. For this reason, the mixing ratio is not described in Table 1.
  • Step S12 in order to prepare 5 g of CZ55-MFO and CZ55-CFO, respectively, a metal salt, citric acid and propylene glycol having a weight [g] shown in Table 2 were mixed, and distilled water half the weight of citric acid was added. Added and stirred. This produced a metal complex with citric acid as a ligand.
  • step S14 this solution was heated to about 150 ° C., whereby an esterification reaction of citric acid and propylene glycol accompanied with the dehydration reaction occurred. Further, by heating to 300 ° C. and holding for half a day, a dehydration reaction occurs due to the OH group not bonded to the metal of citric acid and the OH group of propylene glycol, and the esters are polymerized and polymerized. As a result, a polymer containing a metal complex was produced.
  • step S16 the polymer produced using an electric furnace was heated at 200 ° C. for 2 hours, then heated at 300 ° C. for 2 hours, and then heated at 400 ° C. for 2 hours.
  • the C—C chain and C—H chain of the polymer were cleaved to carbonize the polymer.
  • the carbonized sample was pulverized in an alumina mortar.
  • step S18 the pulverized powder was heated to 700 ° C. at a temperature rising rate of 5 ° C./min, and calcined in the atmosphere for 2 hours. Thereby, a mixed oxide is produced. Thereafter, the mixture was pulverized for 24 hours using a planetary ball mill to form fine particles. This produced CZ55-MFO and CZ55-CFO. Further, as the sample CZ55, Ce 0.5 Zr 0.5 O 2 not containing MnFe 2 O 4 and CoFe 2 O 4 was produced in the same manner using the Pechini method.
  • FIG. 4 is a diagram showing the XRD measurement results of each sample. Cu-K ⁇ rays were used as X-rays.
  • a broad peak having a fluorite structure due to Ce 0.5 Zr 0.5 O 2 is observed in the sample CZ55.
  • a sharp peak of MnFe 2 O 4 having a spinel structure is observed.
  • Some MnFeO 3 phase is observed in sample CZ55-MFO.
  • a sharp peak of CoFe 2 O 4 having the spinel structure is observed.
  • Table 3 is a diagram showing a crystal volume (Crystallite size) and a crystal volume of the Ce 0.5 Zr 0.5 O 2 phase calculated using a WPPD (Whole-Powder-Pattern Decomposition) method. .
  • the crystal volume of the Ce 0.5 Zr 0.5 O 2 phase in each sample is hardly changed. From this, it is considered that there is almost no solid solution of Fe, Mn, Co and the like in the Ce 0.5 Zr 0.5 O 2 phase. In addition, a sample having a small crystallite size is produced.
  • OSC was evaluated for each sample.
  • the evaluation of OSC was performed by calorimetric analysis.
  • a powder sample of about 50 mg to 100 mg is put in a platinum pan.
  • the sample is heated to 400 ° C. in a clean air atmosphere. Hold at 400 ° C. in clean air for 120 minutes. Thereafter, the temperature is maintained, and the atmosphere is switched to an atmosphere containing 5% H 2 gas in Ar gas (H 2 —Ar gas atmosphere) and held for 60 minutes. Thereafter, the temperature is maintained and the atmosphere is switched to a clean air atmosphere.
  • H 2 —Ar gas atmosphere Ar gas
  • oxygen is stored in the sample.
  • Oxygen is released in the H 2 —Ar gas atmosphere.
  • Sample weight changes correspond to oxygen storage and release.
  • the change in the weight of the sample is defined as the molar amount of oxygen absorbed per unit weight OSC ( ⁇ mol-O 2 ⁇ g ⁇ 1 ). Further, ⁇ of Ce 0.5 Zr 0.5 O 2- ⁇ was calculated from the OSC immediately before switching the atmosphere from the H 2 —Ar gas atmosphere to the clean air atmosphere. The theoretical maximum value of ⁇ is 0.25.
  • FIG. 5A is a diagram showing the OSC measurement result of each sample
  • FIG. 5B is a diagram showing ⁇ in each sample.
  • t'-CZ55 and ⁇ -CZ55 is Ce 0.5 Zr 0.5 O 2 of the solid phase each reaction method to prepare using t'-phase of Ce 0.5 Zr 0.5 O 2 and kappa phases.
  • t′-CZ55 (pechini) is Ce 0.5 Zr 0.5 O 2 of the t ′ phase produced by the Pechini method.
  • samples t′-CZ55, ⁇ -CZ55 and t′-CZ55 have low OSC and ⁇ is as small as about 0.01. This ⁇ is 10% or less of the theoretical maximum value.
  • samples CZ55-MFO and CZ55-CFO have high OSC, and ⁇ is about 50% of the theoretical maximum value.
  • Table 4 is a table showing the molar ratio of the spinel metal oxide in the sample in CZ55-MFO and CZ55-CFO and the ratio of the oxygen in the spinel metal oxide phase to the oxygen in the CZ55 phase.
  • the composition of the spinel metal oxide is 15% by volume, the molar ratio of the spinel metal oxide in the sample is 0.1 or less. Furthermore, the amount of oxygen in the spinel metal oxide phase relative to the CZ55 phase is 0.2 or less. Therefore, even if oxygen in the spinel-type metal oxide phase contributes to OSC, the large OSC in FIGS. 5A and 5B cannot be explained. Therefore, the increase in OSC in FIGS. 5A and 5B is considered to be because the spinel metal oxide contributed to the conduction of electrons. Thus, by using a spinel metal oxide, the electron conductivity can be improved, and the OSC can be greatly improved at a low temperature of 400 ° C.
  • FIG. 6 is a diagram showing the OSC cycle characteristics. As shown in FIG. 6, when the cycle is repeated, although the OSC becomes somewhat lower after oxygen storage, excellent cycle characteristics can be obtained. Also, the OSC after oxygen release after each cycle is almost unchanged. This makes this sample particularly excellent as an oxygen release agent.
  • FIG. 7A and FIG. 7B are diagrams showing OSC at 150.degree.
  • the OSC before and after oxygen storage in CZ55-MFO is 11.2 ⁇ mol-O 2 ⁇ g ⁇ 1 .
  • OSC is 7.6 ⁇ mol-O 2 ⁇ g ⁇ 1 in CZ55-CFO.
  • OSC was defined as the OSC difference immediately before switching to a clean air atmosphere and 30 minutes after switching. Thus, oxygen storage and release were confirmed even at 150 ° C.
  • Example 1 As in Example 1, a mixed oxide of Ce 0.5 Zr 0.5 O 2- ⁇ and MnFe 2 O 4 and a combination of Ce 0.5 Zr 0.5 O 2- ⁇ and CoFe 2 O 4 The mixed oxide was found to have excellent OSC characteristics.
  • Example 1 For CZ55-CFO, samples in which the content [volume%] of CoFe 2 O 4 (CFO) was changed were produced.
  • the sample preparation method is the same as in Example 1.
  • OSC was evaluated at 400 ° C. for each sample.
  • the OSC evaluation method is the same as in Example 1.
  • Table 5 is a table showing the OSC measurement and calculation results of each sample.
  • FIG. 8 is a diagram showing OSC with respect to the content of CoFe 2 O 4 .
  • Each dot is a measured value or a calculated value, and a straight line is a line connecting dots.
  • data A is the OSC actually measured for each sample of CZ55-CFO. Data A increases as the content of CoFe 2 O 4 increases.
  • data B is the theoretical maximum value of OSC when oxygen is released only from Ce 0.5 Zr 0.5 O 2- ⁇ .
  • the reason why the data B decreases as the content increases is that the absolute amount of Ce 0.5 Zr 0.5 O 2- ⁇ in the sample decreases as the content increases.
  • the content is about 30% by volume or more, and the data A exceeds the data B. This is because oxygen is released from CoFe 2 O 4 in addition to Ce 0.5 Zr 0.5 O 2- ⁇ .
  • the OSC of a sample having 100% CoFe 2 O 4 at 400 ° C. is measured, it is 1878 ⁇ mol-O 2 ⁇ g ⁇ 1 .
  • the reason why the OSC of CoFe 2 O 4 is large is that CoFe 2 O 4 is reduced to CoO or FeO at 400 ° C., and part of CoO or FeO is further reduced to the metals Co and Fe.
  • CoFe 2 O 4 is added to Ce 1-x Zr x O 2- ⁇ by increasing the conductivity of electrons in the mixed oxide, thereby increasing Ce 0.5 Zr. This is because oxygen release from 0.5 O 2- ⁇ is promoted. If CoFe 2 O 4 promotes the release of oxygen from Ce 0.5 Zr 0.5 O 2- ⁇ , the oxidation and reduction of CoFe 2 O 4 is less and the durability is improved.
  • the amount of oxygen released from CoFe 2 O 4 contained in each sample was calculated from the content of each sample.
  • Oxygen release amount of the sample CoFe 2 O 4 is 100% (i.e. OSC) is 1878 ⁇ mol-O 2 ⁇ g -1, a CoFe 2 O 4 in each sample if Jozure the ratio of CoFe 2 O 4 to the value
  • the amount of oxygen released can be calculated.
  • the amount of oxygen released from CoFe 2 O 4 calculated from the data A of each sample the amount of oxygen released from Ce 0.5 Zr 0.5 O 2- ⁇ in each sample can be calculated.
  • data C is the amount of oxygen released from Ce 0.5 Zr 0.5 O 2- ⁇ calculated in this way.
  • Data R in Table 3 is the ratio of data C / data A.
  • Data R represents the ratio of the oxygen release amount (data C) from Ce 0.5 Zr 0.5 O 2- ⁇ in the OSC (data A) measured for each sample.
  • Data D in Table 5 and FIG. 8 are predicted values of the amount of oxygen released from Ce 0.5 Zr 0.5 O 2- ⁇ when CoFe 2 O 4 does not contribute.
  • Data D was calculated from 57.7 ⁇ mol-O 2 ⁇ g ⁇ 1 , which is data A when the content was 0, and the content.
  • Data CD in Table 5 and FIG. 8 is a value obtained by subtracting data D from data C.
  • Data CD corresponds to the increase in the amount of oxygen released from Ce 0.5 Zr 0.5 O 2- ⁇ due to CoFe 2 O 4 increasing the conductivity of electrons in CZ55-CFO. .
  • the data CD is the largest when the content is 5% by volume, and the data CD becomes smaller when the content is increased from 5% by volume. Further, the data R decreases as the content increases. It shows that the amount of oxygen released from CoFe 2 O 4 increases as the data R decreases.
  • the data CD is large.
  • CoFe 2 O 4 contributes to the occlusion and release of oxygen, and durability may deteriorate.
  • the content of CoFe 2 O 4 is preferably 15% by volume or less. In order to make the data R 70% or more and increase the data CD, the content of CoFe 2 O 4 is more preferably 10% by volume or less.
  • Example 2 an experiment was performed using CoFe 2 O 4 as an example of MFe 2 O 4.
  • M is a divalent metal element
  • M is reducible. Therefore, it is considered that the same result as in Example 2 is obtained even when more general MFe 2 O 4 is used. Therefore, when the oxide is composed of Ce 1-x Zr x O 2- ⁇ and MFe 2 O 4 , the content of MFe 2 O 4 is preferably 15% by volume or less, more preferably 10% by volume or less, and 7% by volume. % Or less is more preferable.
  • the content of MFe 2 O 4 is preferably 1% by volume or more, and more preferably 2% by volume or more.

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Abstract

The present invention provides an oxide that includes: Ce1-xZrxO2- δ (0<x<1 and 0≤δ); and MFe2O4 (M represents a divalent metal element) having a spinel structure. The present invention provides an oxide that includes: Ce1-xZrxO2- δ (0<x<1 and 0≤δ); and a metal oxide having a spinel structure, and that is provided with a layer including the metal oxide in the grain boundary of Ce1-xZrxO2- δ crystal grains. The present invention provides a method for producing an oxide that includes Ce1-xZrxO2- δ (0<x<1 and 0≤δ) and a metal oxide having a spinel structure, the method including: a step for generating a metal complex from metal salts that constitute Ce1-xZrxO2- δ and the metal oxide and generating a polymer that contains the complex; and a step for carbonizing the polymer.

Description

酸化物、酸素貯蔵剤、排気ガス用３元触媒および酸化物の製造方法Oxide, oxygen storage agent, three-way catalyst for exhaust gas, and method for producing oxide
　酸化物、酸素貯蔵剤、排気ガス用３元触媒および酸化物の製造方法に関し、例えばセリアおよびジルコニアを含む酸化物、酸素貯蔵剤、排気ガス用３元触媒および酸化物の製造方法に関する。 The present invention relates to an oxide, an oxygen storage agent, a three-way catalyst for exhaust gas, and a method for producing an oxide.
　自動車等の排気ガスの浄化に３元触媒が用いられている。３元触媒は、排気ガス中の炭化水素（ＨＣ）一酸化炭素（ＣＯ）および窒素酸化物（ＮＯｘ）の３種類を同時に除去する触媒である。触媒として用いられるＰｔ（白金）、Ｐｄ（パラジウム）またはＲｈ（ロジウム）等はこれら３種類を同時に除去できる空燃比（Air/Fuel ratio）の範囲が狭い。そこで、空燃比がこの範囲から外れたときに酸素を吸蔵または放出する酸素貯蔵剤が用いられる（例えば特許文献１－３）。酸素貯蔵剤としてＣｅＯ２－ＺｒＯ２（セリア－ジルコニア）系酸化物が知られている。ガドリウム添加セリウム酸化物とスピネル型Ｆｅ複合酸化物とからなる酸化物をＰｅｃｈｉｎｉ法を用い作製することが知られている（特許文献４、非特許文献１）。 A three-way catalyst is used to purify exhaust gas from automobiles and the like. The three-way catalyst is a catalyst that simultaneously removes three types of hydrocarbon (HC) carbon monoxide (CO) and nitrogen oxide (NO x ) in the exhaust gas. Pt (platinum), Pd (palladium), Rh (rhodium) or the like used as a catalyst has a narrow air / fuel ratio range in which these three types can be removed simultaneously. Therefore, an oxygen storage agent that stores or releases oxygen when the air-fuel ratio is out of this range is used (for example, Patent Documents 1-3). CeO 2 —ZrO 2 (ceria-zirconia) -based oxides are known as oxygen storage agents. It is known that an oxide composed of gadolinium-added cerium oxide and spinel-type Fe composite oxide is manufactured using the Pecini method (Patent Document 4, Non-Patent Document 1).
特開２０１３－２４１３２８号公報JP 2013-241328 A 特開２０１５－１１２５６０号公報JP2015-112560A 特開２０１１－４６５６７号公報JP 2011-46567 A 国際公開第２００３／８４８９４号International Publication No. 2003/84894
　ＣｅＯ２－ＺｒＯ２系酸化物の酸素貯蔵能（ＯＳＣ：Oxygen Storage Capacity）特性は十分ではない。例えば、比較的低温においてＯＳＣ特性が低下する。 Oxygen storage capability of CeO 2 -ZrO 2 based oxide (OSC: Oxygen Storage Capacity) characteristic is not sufficient. For example, OSC characteristics deteriorate at a relatively low temperature.
　本発明は、上記課題に鑑みなされたものであり、ＯＳＣ特性を向上させることを目的とする。 The present invention has been made in view of the above problems, and aims to improve OSC characteristics.
　本発明は、Ｃｅ１－ｘＺｒｘＯ２－δ（０＜ｘ＜１かつ０≦δ）とスピネル構造を有するＭＦｅ２Ｏ４（Ｍは２価をとる金属元素）とを含むことを特徴とする酸化物である。 The present invention includes Ce 1-x Zr x O 2-δ (0 <x <1 and 0 ≦ δ) and MFe 2 O 4 having a spinel structure (M is a divalent metal element). It is an oxide.
　上記構成において、前記ＭはＭｎまたはＣｏである構成とすることができる。 In the above configuration, the M may be Mn or Co.
　上記構成において、前記ＭＦｅ２Ｏ４の含有量は３３体積％未満である構成とすることができる。 In the above structure, the content of the MFe 2 O 4 may be configured to be less than 33% by volume.
　上記構成において、前記酸化物は前記Ｃｅ１－ｘＺｒｘＯ２－δと前記ＭＦｅ２Ｏ４とからなり、前記ＭＦｅ２Ｏ４の含有量は１５体積％以下である構成とすることができる。 In the above structure, the oxide is composed of the Ce 1-x Zr x O 2-δ and the MFe 2 O 4, and the content of the MFe 2 O 4 may be 15% by volume or less. .
　上記構成において、前記ＭはＣｏである構成とすることができる。 In the above configuration, the M may be Co.
　本発明は、Ｃｅ１－ｘＺｒｘＯ２－δ（０＜ｘ＜１、０≦δ）とスピネル構造を有する金属酸化物とを含む、前記Ｃｅ１－ｘＺｒｘＯ２－δの結晶粒の粒界に前記金属酸化物を含む層を備えることを特徴とする酸化物である。 The present invention provides a crystal of Ce 1-x Zr x O 2-δ containing Ce 1-x Zr x O 2-δ (0 <x <1, 0 ≦ δ) and a metal oxide having a spinel structure. An oxide comprising a layer containing the metal oxide at a grain boundary.
　上記構成において、前記金属酸化物を含む層は電子伝導層である構成とすることができる。 In the above structure, the layer containing the metal oxide may be an electron conductive layer.
　本発明は、上記酸化物を含むことを特徴とする酸素貯蔵剤である。 The present invention is an oxygen storage agent comprising the above oxide.
　本発明は上記酸素貯蔵剤を含むことを特徴とする排気ガス用３元触媒である。 The present invention is a three-way catalyst for exhaust gas characterized by containing the above oxygen storage agent.
　本発明は、Ｃｅ１－ｘＺｒｘＯ２－δ（０＜ｘ＜１かつ０≦δ）とスピネル構造を有する金属酸化物とを含む酸化物を製造する方法であって、前記Ｃｅ１－ｘＺｒｘＯ２－δと前記金属酸化物とを構成する金属の塩から前記金属の錯体を生成し、前記錯体を含む高分子を生成する工程と、前記高分子を炭化する工程と、を含むことを特徴とする酸化物の製造方法である。 The present invention provides a method of producing the Ce 1-x Zr x O 2 -δ (0 <x <1 and 0 ≦ [delta]) oxide containing a metal oxide having a spinel structure, the Ce 1- forming a complex of the metal from a metal salt constituting x Zr x O 2-δ and the metal oxide, producing a polymer containing the complex, and carbonizing the polymer. It is the manufacturing method of the oxide characterized by including.
　本発明によれば、ＯＳＣを向上させることができる。 According to the present invention, OSC can be improved.
図１（ａ）は、Ｃｅ０．５Ｚｒ０．５Ｏ２におけるδを示す図である。図１（ｂ）は、酸素吸蔵および酸素放出のときの反応を模式化した図である。1 (a) is a diagram showing a δ at Ce 0.5 Zr 0.5 O 2. FIG. 1 (b) is a diagram schematically showing the reaction during oxygen storage and oxygen release. 図２は、Ｐｅｃｈｉｎｉ法を用い混合酸化物の作製方法を示すフローチャートである。FIG. 2 is a flowchart showing a method for producing a mixed oxide using the Pechini method. 図３（ａ）は、Ｐｅｃｈｉｎｉ法を用い作製した混合酸化物の模式図である。図３（ｂ）は、実施形態２に係る３元触媒の断面図である。FIG. 3A is a schematic diagram of a mixed oxide produced using the Pecini method. FIG. 3B is a cross-sectional view of the three-way catalyst according to the second embodiment. 図４は、各サンプルのＸＲＤ測定結果を示す図である。FIG. 4 is a diagram showing the XRD measurement results of each sample. 図５（ａ）は、各サンプルのＯＳＣの測定結果を示す図であり、図５（ｂ）は各サンプルにおけるδを示す図である。FIG. 5A is a diagram showing the OSC measurement result of each sample, and FIG. 5B is a diagram showing δ in each sample. 図６は、ＯＳＣサイクル特性を示す図である。FIG. 6 is a diagram showing the OSC cycle characteristics. 図７（ａ）および図７（ｂ）は、１５０℃におけるＯＳＣ特性を示す図である。FIG. 7A and FIG. 7B are diagrams showing OSC characteristics at 150 ° C. 図８は、ＣｏＦｅ２Ｏ４の含有量に対するＯＳＣを示す図である。FIG. 8 is a diagram showing OSC with respect to the content of CoFe 2 O 4 .
　本発明の実施形態について説明する。 Embodiments of the present invention will be described.
　まず、３元触媒に酸素貯蔵剤に用いられるＣｅＯ２－ＺｒＯ２系酸化物について説明する。酸素貯蔵剤は、３元触媒において酸素が不足しているとき酸素を放出、酸素が過剰なとき酸素を吸蔵する。これにより、空燃比が理想の範囲からずれても排気ガス中の炭化水素、一酸化炭素および窒素酸化物の３種類を同時に除去することができる。 First, a CeO 2 —ZrO 2 -based oxide used as an oxygen storage agent for a three-way catalyst will be described. The oxygen storage agent releases oxygen when oxygen is insufficient in the three-way catalyst, and stores oxygen when oxygen is excessive. Thereby, even if the air-fuel ratio deviates from the ideal range, three types of hydrocarbons, carbon monoxide and nitrogen oxides in the exhaust gas can be removed simultaneously.
　ＣｅＯ２は立方晶蛍石型結晶構造を有する。ＣｅＯ２は以下の反応式により酸素を吸蔵および放出する。
　酸素放出　ＣｅＯ２→ＣｅＯ２－δ＋δ／２Ｏ２
　酸素吸蔵　ＣｅＯ２－δ＋δ／２Ｏ２→ＣｅＯ２
　ＣｅＯ２のＣｅイオンはＣｅ４＋であり、全てのＣｅ４＋がＣｅ３＋に還元されたとき最もδが大きくなる。このときδ＝０．５である。 CeO 2 has a cubic fluorite-type crystal structure. CeO 2 occludes and releases oxygen according to the following reaction formula.
Oxygen release CeO 2 → CeO 2-δ + δ / 2O 2
Oxygen storage CeO 2-δ + δ / 2O 2 → CeO 2
The Ce ion of CeO 2 is Ce 4+ , and δ becomes the largest when all Ce 4+ is reduced to Ce 3+ . At this time, δ = 0.5.
　ＣｅＯ２単体では結晶表面の酸素が主にＯＳＣ特性に寄与するが、ＣｅＯ２－ＺｒＯ２では結晶内部の酸素もＯＳＣに寄与する。このため、ＣｅＯ２－ＺｒＯ２系酸化物は高いＯＳＣを有する。Ｃｅ１－ｘＺｒｘＯ２では、ｘ＝０．５近傍で最も高いＯＳＣ特性となる。Ｃｅ０．５Ｚｒ０．５Ｏ２において酸素を放出すると、Ｃｅ０．５Ｚｒ０．５Ｏ２－δとなる。Ｚｒイオンの価数は変わらないとすると、最も大きいδは０．２５である。Ｃｅ１－ｘＺｒｘＯ２にはｔ´相およびκ相等の複数の相が存在する。酸素貯蔵剤としては、主にｔ´相またはκ相が用いられる。ｔ´相は正方晶系の相である。κ相はパイロクロア類似構造の相である。 In the case of CeO 2 alone, oxygen on the crystal surface mainly contributes to OSC characteristics, but in CeO 2 —ZrO 2 , oxygen inside the crystal also contributes to OSC. Therefore, CeO 2 —ZrO 2 -based oxide has a high OSC. Ce 1-x Zr x O 2 has the highest OSC characteristics near x = 0.5. When oxygen is released at Ce 0.5 Zr 0.5 O 2, the Ce 0.5 Zr 0.5 O 2-δ . If the valence of the Zr ion is not changed, the largest δ is 0.25. Ce 1-x Zr x O 2 has a plurality of phases such as a t ′ phase and a κ phase. As the oxygen storage agent, t ′ phase or κ phase is mainly used. The t ′ phase is a tetragonal phase. The κ phase is a phase with a pyrochlore-like structure.
　ｔ´相およびκ相のＣｅ０．５Ｚｒ０．５Ｏ２のＣＳＯ特性を測定した。測定方法は後述する実施例と同様である。図１（ａ）は、Ｃｅ０．５Ｚｒ０．５Ｏ２におけるδを示す図である。図１（ａ）のδは、酸素を放出させたときのδである。図１（ａ）に示すように、８００℃においては、δが大きい。特にκ相では、理論的最大値のδ＝０．２５にほぼ一致している。ｔ´相でもδは０．１５を越えている。一方、４００℃においては、ｔ´相およびκ相ともδが０．０１程度と非常に小さい。 CSO characteristics of Ce 0.5 Zr 0.5 O 2 of t ′ phase and κ phase were measured. The measuring method is the same as in the examples described later. 1 (a) is a diagram showing a δ at Ce 0.5 Zr 0.5 O 2. In FIG. 1A, δ is δ when oxygen is released. As shown in FIG. 1A, at 800 ° C., δ is large. In particular, in the κ phase, the theoretical maximum value δ = 0.25 is almost coincident. Even in the t ′ phase, δ exceeds 0.15. On the other hand, at 400 ° C., both t ′ phase and κ phase have a very small δ of about 0.01.
　このように、Ｃｅ１－ｘＺｒｘＯ２は比較的低温の排気ガスに対しては酸素貯蔵剤として十分に機能しない。例えばハイブリッド車等では排気ガスの温度が低く、Ｃｅ１－ｘＺｒｘＯ２のＯＳＣ特性では不十分である。 Thus, Ce 1-x Zr x O 2 does not function sufficiently as an oxygen storage agent for relatively low temperature exhaust gas. For example, in a hybrid vehicle or the like, the exhaust gas temperature is low, and the OSC characteristic of Ce 1-x Zr x O 2 is insufficient.
　発明者らは、低温においてＣｅ１－ｘＺｒｘＯ２のＯＳＣ特性が低い理由について考察した。図１（ｂ）は、酸素吸蔵および酸素放出のときの反応を模式化した図である。図１（ｂ）に示すように、酸素を吸蔵するとき、ＣｅＯ２－ＺｒＯ２系酸化物の内部から表面に酸素の空孔（vacancy）ＶＯ ・・および電子２ｅ－が伝導し、酸素イオンＯ２－が表面から内部に伝導する。酸素を放出するとき、ＣｅＯ２－ＺｒＯ２系酸化物の内部から表面に酸素イオンＯ２－が伝導し、酸素空孔ＶＯ ・・および電子２ｅ－が表面から内部に伝導する。Ｃｅ１－ｘＺｒｘＯ２のＯＳＣ特性は、酸素イオンＯ２－の拡散と電子e－の拡散のうち電子e－の拡散で律速されているのではないかと推測した。 The inventors considered the reason why Ce 1-x Zr x O 2 has low OSC characteristics at low temperatures. FIG. 1 (b) is a diagram schematically showing the reaction during oxygen storage and oxygen release. As shown in FIG. 1B, when occluding oxygen, oxygen vacancy V O ·· and electrons 2e − are conducted from the inside of the CeO 2 —ZrO 2 oxide to the surface, and oxygen ions O 2− is conducted from the surface to the inside. When oxygen is released, oxygen ions O 2− are conducted from the inside of the CeO 2 —ZrO 2 -based oxide to the surface, and oxygen vacancies V 2 O ·· and electrons 2e − are conducted from the surface to the inside. It was speculated that the OSC characteristics of Ce 1-x Zr x O 2 might be limited by the diffusion of electron e − among the diffusion of oxygen ion O 2− and the diffusion of electron e − .
（実施形態１）
　実施形態１の混合酸化物は、Ｃｅ１－ｘＺｒｘＯ２－δとスピネル構造を有する金属酸化物とを含む。例えば、混合酸化物は、Ｃｅ１－ｘＺｒｘＯ２－δとスピネル構造を有する金属酸化物とからなる。スピネル構造を有する金属酸化物は、Ｃｅ１－ｘＺｒｘＯ２との反応が生じにくく、かつ電子伝導性が高い。このため、混合酸化物内の電子の伝導性を高めＯＳＣ特性を高めることができる。 (Embodiment 1)
The mixed oxide of Embodiment 1 includes Ce 1-x Zr x O 2-δ and a metal oxide having a spinel structure. For example, the mixed oxide is made of Ce 1-x Zr x O 2-δ and a metal oxide having a spinel structure. A metal oxide having a spinel structure hardly reacts with Ce 1-x Zr x O 2 and has high electron conductivity. For this reason, the conductivity of electrons in the mixed oxide can be increased and the OSC characteristics can be improved.
　スピネル構造を有する金属酸化物の中で、ＭＦｅ２Ｏ４（Ｍは２価をとる金属元素）は電子伝導性が高い。よって、スピネル構造を有する金属酸化物にＭＦｅ２Ｏ４を用いることでＯＳＣ特性を高めることができる。Ｍは、例えばＣｏ（コバルト）、Ｍｎ（マンガン）、Ｆｅ（鉄）、Ｃｕ（銅）、Ｃｒ（クロム）、またはＮｉ（ニッケル）等の遷移金属である。また、Ｍは、例えばＭｇ（マグネシウム）等の２族元素でもよい。さらに、Ｍとしてこれら元素を複数含んでもよい。また、例えばＬｉ（リチウム）等の１族の元素をＦｅ等の遷移金属と組み合わせて、（Ｌｉ０．５Ｆｅ０．５）のように、２価ではない金属元素を組み合わせて、見かけ上２価の金属元素としてもよい。なお、ＭＦｅ２Ｏ４は、実施形態の効果が得られる範囲で化学量論的な組成がずれていてもよい。また、不純物を含んでいてもよい。 Among metal oxides having a spinel structure, MFe 2 O 4 (M is a divalent metal element) has high electron conductivity. Therefore, OSC characteristics can be improved by using MFe 2 O 4 for the metal oxide having a spinel structure. M is a transition metal such as Co (cobalt), Mn (manganese), Fe (iron), Cu (copper), Cr (chromium), or Ni (nickel). Further, M may be a Group 2 element such as Mg (magnesium). Furthermore, M may contain a plurality of these elements. Further, for example, a group 1 element such as Li (lithium) is combined with a transition metal such as Fe, and a metal element that is not divalent, such as (Li 0.5 Fe 0.5 ), is combined, and apparently 2 A valent metal element may be used. Note that MFe 2 O 4 may have a stoichiometric composition within a range in which the effect of the embodiment can be obtained. Further, impurities may be included.
　Ｃｅ１－ｘＺｒｘＯ２－δにおけるｘは０＜ｘ＜１であればよい。高いＯＳＣ特性を実現するため、０．２≦ｘ≦０．８が好ましく、０．３≦ｘ≦０．７がより好ましく、０．４≦ｘ≦０．６がさらに好ましい。また、０≦δであればよい。Ｃｅ０．５Ｚｒ０．５Ｏ２－δのとき論理的には０≦δ≦０．２５であり、ｘが０に近いとき０≦δ≦０．５である。 X in Ce 1-x Zr x O 2-δ may be 0 <x <1. In order to realize high OSC characteristics, 0.2 ≦ x ≦ 0.8 is preferable, 0.3 ≦ x ≦ 0.7 is more preferable, and 0.4 ≦ x ≦ 0.6 is further preferable. Further, 0 ≦ δ may be satisfied. When Ce 0.5 Zr 0.5 O 2-δ , logically 0 ≦ δ ≦ 0.25, and when x is close to 0, 0 ≦ δ ≦ 0.5.
　実施形態１に係る混合酸化物は例えばＰｅｃｈｉｎｉ法を用い作製することができる。図２は、Ｐｅｃｈｉｎｉ法を用い混合酸化物の作製方法を示すフローチャートである。図２に示すように、金属塩を準備する（ステップＳ１０）。金属塩は、Ｃｅ、Ｚｒおよびスピネル構造を有する金属酸化物を構成する金属の塩である。金属酸化物がＭＦｅ２Ｏ４の場合、準備する金属塩は、Ｃｅ、Ｚｒ、ＭおよびＦｅの金属塩である。金属塩として、例えば硝酸塩、硫酸塩または金属塩化物を用いることができる。 The mixed oxide according to Embodiment 1 can be manufactured using, for example, the Pecini method. FIG. 2 is a flowchart showing a method for producing a mixed oxide using the Pechini method. As shown in FIG. 2, a metal salt is prepared (step S10). The metal salt is a salt of a metal constituting a metal oxide having a Ce, Zr and spinel structure. When the metal oxide is MFe 2 O 4 , the prepared metal salt is a metal salt of Ce, Zr, M, and Fe. As metal salts, for example, nitrates, sulfates or metal chlorides can be used.
　金属塩から金属錯体を生成する（ステップＳ１２）。配位子としては、例えばクエン酸等の有機配位子を用いる。配位子としてはキレート配位子が好ましい。例えば金属塩を多価アルコール等に溶解させ、配位子となる化学物質（例えばクエン酸）を過剰に加えることで、金属錯体を生成する。 A metal complex is generated from the metal salt (step S12). As the ligand, for example, an organic ligand such as citric acid is used. The ligand is preferably a chelate ligand. For example, a metal complex is generated by dissolving a metal salt in a polyhydric alcohol or the like and adding an excessive chemical substance (for example, citric acid) to be a ligand.
　金属錯体を含む高分子を生成する（ステップＳ１４）。例えば、金属錯体と重合開始剤を含む溶液を加熱することにより高分子を生成する。例えば重合開始剤が多価アルコールであり、配位子がクエン酸である場合、クエン酸と多価アルコールのエステル化反応が起こる。さらに、加熱すると、クエン酸の金属と反応していないＯＨ基と多価アルコールのＯＨ基とにより脱水反応が起こる。これによりエステル同士が重合されポリマー化する。生成された高分子は例えばゲル状である。 A polymer containing a metal complex is generated (step S14). For example, a polymer is produced by heating a solution containing a metal complex and a polymerization initiator. For example, when the polymerization initiator is a polyhydric alcohol and the ligand is citric acid, an esterification reaction between citric acid and the polyhydric alcohol occurs. Furthermore, when heated, a dehydration reaction occurs due to the OH group not reacting with the metal of citric acid and the OH group of the polyhydric alcohol. Thereby, esters are polymerized and polymerized. The produced polymer is, for example, a gel.
　高分子を炭化する（ステップＳ１６）。例えば、ポリマー化した高分子を加熱すると、Ｃ－Ｃ鎖および／またはＣ－Ｈ鎖が切れる。その後、炭化した高分子を粉砕する。仮焼する（ステップＳ１８）。例えば粉砕した粉末を高温で仮焼きする。これにより、混合酸化物が作製できる。このように作製した混合酸化物では、Ｃｅ１－ｘＺｒｘＯ２－δとスピネル構造を有する金属酸化物との均一な混合状態が保たれる。 The polymer is carbonized (step S16). For example, when a polymerized polymer is heated, a CC chain and / or a CH chain is broken. Thereafter, the carbonized polymer is pulverized. Calcination is performed (step S18). For example, the pulverized powder is calcined at a high temperature. Thereby, a mixed oxide can be produced. In the mixed oxide thus produced, a uniform mixed state of Ce 1-x Zr x O 2-δ and the metal oxide having a spinel structure is maintained.
　また、Ｐｅｃｈｉｎｉ法を用いＣｅ１－ｘＺｒｘＯ２－δとスピネル型金属酸化物からなる混合酸化物を作成すると、特許文献４および非特許文献１に記載されているように、Ｃｅ１－ｘＺｒｘＯ２－δの結晶粒の界面にスピネル型金属酸化物を含む層が形成されると考えられる。 Also, creating a Ce 1-x Zr x O 2 -δ and mixed oxides consisting of spinel-type metal oxide with Pechini method, as described in Patent Document 4 and Non-Patent Document 1, Ce 1- the grain at the interface x Zr x O 2-δ believed layer containing a spinel-type metal oxide is formed.
　図３（ａ）は、Ｐｅｃｈｉｎｉ法を用い作製した混合酸化物の模式図である。図３（ａ）に示すように、Ｃｅ１－ｘＺｒｘＯ２－δ相の結晶粒１２とスピネル型金属酸化物相の結晶粒１４が存在する。結晶粒１２の界面に層１６が形成されている。結晶粒１２および１４の粒径は例えば数ｎｍから１００ｎｍである。層１６の厚さは例えば１ｎｍから数十ｎｍである。層１６は、スピネル型金属酸化物を含み電子伝導層として機能する。結晶粒１４および層１６を介し混合酸化物１０内の電子の伝導性が高くなる。よって、酸素吸蔵および酸素放出におけるＯＳＣ特性が向上する。 FIG. 3A is a schematic diagram of a mixed oxide produced using the Pecini method. As shown in FIG. 3A, there are Ce 1-x Zr x O 2-δ phase crystal grains 12 and spinel-type metal oxide phase crystal grains 14. A layer 16 is formed at the interface of the crystal grains 12. The grain size of the crystal grains 12 and 14 is, for example, several nm to 100 nm. The thickness of the layer 16 is, for example, 1 nm to several tens of nm. The layer 16 includes a spinel metal oxide and functions as an electron conductive layer. The conductivity of electrons in the mixed oxide 10 is increased through the crystal grains 14 and the layer 16. Therefore, OSC characteristics in oxygen storage and oxygen release are improved.
　２つの物質相の混合状態において、１つの物質相が３次元的に接続されるためには、１つの物質相の含有量は全体の３３体積％以上が求められる。Ｃｅ１－ｘＺｒｘＯ２－δにスピネル型金属酸化物を添加した場合、電子伝導に寄与するように、スピネル型金属酸化物相を３次元的に接続させるためには、混合酸化物中のスピネル型金属酸化物の含有量を３３体積％以上とすることになる。スピネル型金属酸化物を増やすと単位重量当たりのＯＳＣ特性が低下してしまう。 In order to connect one substance phase three-dimensionally in a mixed state of two substance phases, the content of one substance phase is required to be 33% by volume or more of the whole. When a spinel metal oxide is added to Ce 1-x Zr x O 2-δ , in order to connect the spinel metal oxide phase three-dimensionally so as to contribute to electronic conduction, The content of the spinel-type metal oxide is 33% by volume or more. When the spinel type metal oxide is increased, the OSC characteristic per unit weight is lowered.
　実施形態１によれば、図３（ａ）のように、結晶粒１２の界面に電子伝導性の高いスピネル構造を有する金属酸化物を含む層１６が形成されている。これにより、スピネル型金属酸化物の含有量が３３％体積未満であっても、電子伝導に寄与する結晶粒１４および層１６が３次元的にネットワークを形成する。よって、電子の伝導性が高くなりＯＳＣ特性が向上する。スピネル型金属酸化物の含有量は３０体積％以下が好ましく、２５体積％以下がより好ましく、２０体積％以下がさらに好ましい。また、３次元ネットワークを形成するために、スピネル型金属酸化物の含有量は１体積％以上が好ましく、２体積％以上がより好ましい。 According to Embodiment 1, a layer 16 containing a metal oxide having a spinel structure with high electron conductivity is formed at the interface of crystal grains 12 as shown in FIG. Thereby, even if the content of the spinel metal oxide is less than 33% by volume, the crystal grains 14 and the layer 16 that contribute to electron conduction form a three-dimensional network. Accordingly, electron conductivity is increased and OSC characteristics are improved. The content of the spinel metal oxide is preferably 30% by volume or less, more preferably 25% by volume or less, and further preferably 20% by volume or less. In order to form a three-dimensional network, the content of the spinel metal oxide is preferably 1% by volume or more, and more preferably 2% by volume or more.
（実施形態２）
　実施形態２は、実施形態１の混合酸化物を用いた３元触媒である。図３（ｂ）は、実施形態２に係る３元触媒の断面図である。図３（ｂ）に示すように、サポート材２０に酸素貯蔵剤２２が担持されている。酸素貯蔵剤２２に触媒金属２４が担持されている。サポート材２０は例えばアルミナ等である。酸素貯蔵剤２２は実施形態１に係る混合酸化物である。触媒金属２４は、例えばＰｔ、Ｐｄ、Ｒｈ等の貴金属である。酸素貯蔵剤２２と触媒金属２４がサポート材に担持されていてもよい。 (Embodiment 2)
The second embodiment is a three-way catalyst using the mixed oxide of the first embodiment. FIG. 3B is a cross-sectional view of the three-way catalyst according to the second embodiment. As shown in FIG. 3B, an oxygen storage agent 22 is supported on the support material 20. A catalyst metal 24 is supported on the oxygen storage agent 22. The support material 20 is alumina or the like, for example. The oxygen storage agent 22 is the mixed oxide according to the first embodiment. The catalyst metal 24 is a noble metal such as Pt, Pd, or Rh. The oxygen storage agent 22 and the catalyst metal 24 may be supported on the support material.
　実施形態１の混合酸化物を酸素貯蔵剤として用いることで、酸素貯蔵剤のＯＳＣ特性を向上できる。例えば比較的低温においてもＯＳＣ特性が向上する。実施形態１の混合酸化物を用いた酸素貯蔵剤を排気ガス用３元触媒とすることで、ハイブリッド車等の排気ガス温度が低い場合において、３元触媒として使用することができる。 By using the mixed oxide of Embodiment 1 as an oxygen storage agent, the OSC characteristics of the oxygen storage agent can be improved. For example, the OSC characteristics are improved even at a relatively low temperature. By using the oxygen storage agent using the mixed oxide of Embodiment 1 as a three-way catalyst for exhaust gas, the exhaust gas temperature of a hybrid vehicle or the like can be used as a three-way catalyst.
　混合酸化物としてサンプルＣＺ５５－ＭＦＯおよびＣＺ５５－ＣＦＯを作製した。各サンプルの酸化物および含有量は以下である。
ＣＺ５５－ＭＦＯ：Ｃｅ０．５Ｚｒ０．５Ｏ２、１５体積％ＭｎＦｅ２Ｏ４
ＣＺ５５－ＣＦＯ：Ｃｅ０．５Ｚｒ０．５Ｏ２、１５体積％ＣｏＦｅ２Ｏ４ Samples CZ55-MFO and CZ55-CFO were prepared as mixed oxides. The oxide and content of each sample is as follows.
CZ55-MFO: Ce 0.5 Zr 0.5 O 2 , 15% by volume MnFe 2 O 4
CZ55-CFO: Ce 0.5 Zr 0.5 O 2 , 15% by volume CoFe 2 O 4
　Ｐｅｃｈｉｎｉ法を用いたＣＺ５５－ＭＦＯおよびＣＺ５５－ＣＦＯの作製方法について説明する。図２のステップＳ１０において、表１の金属塩を準備した。Ｃｅ、Ｍｎ、ＣｏおよびＦｅの塩として硝酸塩を用い、Ｚｒの塩として酸化塩化物を用いた。各金属塩の純度は９９．９原子％である。金属：クエン酸：プロピレングリコールの混合比はＣｅ、Ｃｏ、Ｆｅでは１：３：３、Ｚｒでは１：６：６とした。Ｍｎの硝酸塩Ｍｎ（ＮＯ３）２・６Ｈ２Ｏは融点が２６℃のため、そのまま液体原料として用いた。このため、表１には混合比を記載していない。
Figure JPOXMLDOC01-appb-T000001
 A method for manufacturing CZ55-MFO and CZ55-CFO using the Pecini method will be described. In step S10 of FIG. 2, the metal salts shown in Table 1 were prepared. Nitrate was used as the salt of Ce, Mn, Co, and Fe, and oxide chloride was used as the salt of Zr. The purity of each metal salt is 99.9 atomic%. The mixing ratio of metal: citric acid: propylene glycol was 1: 3: 3 for Ce, Co, and Fe, and 1: 6: 6 for Zr. Since Mn nitrate Mn (NO 3 ) 2 .6H 2 O has a melting point of 26 ° C., it was directly used as a liquid raw material. For this reason, the mixing ratio is not described in Table 1.
Figure JPOXMLDOC01-appb-T000001
　ステップＳ１２において、ＣＺ５５－ＭＦＯおよびＣＺ５５－ＣＦＯを各々５ｇ作製するため、表２の重量［ｇ］の金属塩、クエン酸およびプロピレングリコールを混合し、クエン酸の重量の１／２の蒸留水を加え、攪拌した。これによりクエン酸を配位子とする金属錯体を生成した。
Figure JPOXMLDOC01-appb-T000002
 In Step S12, in order to prepare 5 g of CZ55-MFO and CZ55-CFO, respectively, a metal salt, citric acid and propylene glycol having a weight [g] shown in Table 2 were mixed, and distilled water half the weight of citric acid was added. Added and stirred. This produced a metal complex with citric acid as a ligand.
Figure JPOXMLDOC01-appb-T000002
　ステップＳ１４において、この溶液を約１５０℃に加熱することで、脱水反応にともなうクエン酸とプロピレングリコールのエステル化反応が生じた。さらに、３００℃に加熱し半日保持することで、クエン酸の金属と結合していないＯＨ基とプロピレングリコールのＯＨ基により脱水反応が生じエステル同士が重合されポリマー化する。これにより金属錯体を含む高分子が生成された。 In step S14, this solution was heated to about 150 ° C., whereby an esterification reaction of citric acid and propylene glycol accompanied with the dehydration reaction occurred. Further, by heating to 300 ° C. and holding for half a day, a dehydration reaction occurs due to the OH group not bonded to the metal of citric acid and the OH group of propylene glycol, and the esters are polymerized and polymerized. As a result, a polymer containing a metal complex was produced.
　ステップＳ１６において、電気炉を用い生成した高分子を２００℃で２時間加熱し、その後３００℃で２時間加熱し、その後４００℃で２時間加熱した。これにより、高分子のＣ－Ｃ鎖およびＣ－Ｈ鎖が切断され高分子が炭化された。炭化後の試料をアルミナ乳鉢で粉砕した。 In step S16, the polymer produced using an electric furnace was heated at 200 ° C. for 2 hours, then heated at 300 ° C. for 2 hours, and then heated at 400 ° C. for 2 hours. As a result, the C—C chain and C—H chain of the polymer were cleaved to carbonize the polymer. The carbonized sample was pulverized in an alumina mortar.
　ステップＳ１８において、粉砕した粉末を５℃／分の昇温速度で７００℃まで昇温し、大気中で２時間仮焼した。これにより混合酸化物が作製される。その後、遊星ボールミルを用い２４時間粉砕することで微粒子化した。これにより、ＣＺ５５－ＭＦＯおよびＣＺ５５－ＣＦＯを作製した。また、サンプルＣＺ５５として同様にＰｅｃｈｉｎｉ法を用いＭｎＦｅ２Ｏ４およびＣｏＦｅ２Ｏ４を含まないＣｅ０．５Ｚｒ０．５Ｏ２を作製した。 In step S18, the pulverized powder was heated to 700 ° C. at a temperature rising rate of 5 ° C./min, and calcined in the atmosphere for 2 hours. Thereby, a mixed oxide is produced. Thereafter, the mixture was pulverized for 24 hours using a planetary ball mill to form fine particles. This produced CZ55-MFO and CZ55-CFO. Further, as the sample CZ55, Ce 0.5 Zr 0.5 O 2 not containing MnFe 2 O 4 and CoFe 2 O 4 was produced in the same manner using the Pechini method.
　作製された各サンプルのＸＲＤ（X‐Ray Diffraction）測定を行なった。図４は、各サンプルのＸＲＤ測定結果を示す図である。Ｘ線としてＣｕ－Ｋα線を用いた。図４に示すように、サンプルＣＺ５５では、Ｃｅ０．５Ｚｒ０．５Ｏ２に起因した蛍石型構造のブロードなピークが観察される。サンプルＣＺ５５－ＭＦＯでは、蛍石型構造のピークに加え、スピネル型構造のＭｎＦｅ２Ｏ４の先鋭なピークが観察される。サンプルＣＺ５５－ＭＦＯに若干のＭｎＦｅＯ３相が観察される。サンプルＣＺ５５－ＣＦＯでは、蛍石型構造のピークに加え、スピネル型構造のＣｏＦｅ２Ｏ４の先鋭なピークが観察される。 XRD (X-Ray Diffraction) measurement of each produced sample was performed. FIG. 4 is a diagram showing the XRD measurement results of each sample. Cu-Kα rays were used as X-rays. As shown in FIG. 4, in the sample CZ55, a broad peak having a fluorite structure due to Ce 0.5 Zr 0.5 O 2 is observed. In the sample CZ55-MFO, in addition to the peak of the fluorite structure, a sharp peak of MnFe 2 O 4 having a spinel structure is observed. Some MnFeO 3 phase is observed in sample CZ55-MFO. In the sample CZ55-CFO, in addition to the peak of the fluorite structure, a sharp peak of CoFe 2 O 4 having the spinel structure is observed.
　表３は、ＷＰＰＤ（Whole-Powder-Pattern Decomposition）法を用い算出されたＣｅ０．５Ｚｒ０．５Ｏ２相の結晶体積（Cell volume）および結晶子サイズ（Crystallite size）を示す図である。表３のように、各サンプルにおけるＣｅ０．５Ｚｒ０．５Ｏ２相の結晶体積はほとんど変わらない。このことから、Ｃｅ０．５Ｚｒ０．５Ｏ２相にＦｅ、ＭｎおよびＣｏ等の固溶はほとんどないと考えられる。また、結晶子サイズの小さなサンプルが作製されている。
Figure JPOXMLDOC01-appb-T000003
 Table 3 is a diagram showing a crystal volume (Crystallite size) and a crystal volume of the Ce 0.5 Zr 0.5 O 2 phase calculated using a WPPD (Whole-Powder-Pattern Decomposition) method. . As shown in Table 3, the crystal volume of the Ce 0.5 Zr 0.5 O 2 phase in each sample is hardly changed. From this, it is considered that there is almost no solid solution of Fe, Mn, Co and the like in the Ce 0.5 Zr 0.5 O 2 phase. In addition, a sample having a small crystallite size is produced.
Figure JPOXMLDOC01-appb-T000003
　各サンプルについてＯＳＣを評価した。ＯＳＣの評価は熱分量分析により行なった。５０ｍｇから１００ｍｇ程度の粉末状のサンプルを白金パンに入れる。サンプルをクリーン空気雰囲気中で４００℃まで昇温する。４００℃においてクリーン空気中で１２０分間保持する。その後、温度を維持しＡｒガス中に５％のＨ２ガスを含む雰囲気（Ｈ２－Ａｒガス雰囲気）に切り替え、６０分保持する。その後、温度を維持し雰囲気をクリーン空気雰囲気に切り替える。クリーン空気中ではサンプルに酸素が吸蔵される。Ｈ２－Ａｒガス雰囲気中では酸素が放出される。この過程においてサンプルの重量を測定する。サンプルの重量変化は酸素の吸蔵および放出に対応する。サンプルの重量変化を単位重さ当たりの酸素のモル吸出量ＯＳＣ（μｍｏｌ－Ｏ２・ｇ－１）とする。また、雰囲気をＨ２－Ａｒガス雰囲気からクリーン空気雰囲気に切り替える直前のＯＳＣからＣｅ０．５Ｚｒ０．５Ｏ２－δのδを算出した。δの理論的最大値は０．２５である。 OSC was evaluated for each sample. The evaluation of OSC was performed by calorimetric analysis. A powder sample of about 50 mg to 100 mg is put in a platinum pan. The sample is heated to 400 ° C. in a clean air atmosphere. Hold at 400 ° C. in clean air for 120 minutes. Thereafter, the temperature is maintained, and the atmosphere is switched to an atmosphere containing 5% H 2 gas in Ar gas (H 2 —Ar gas atmosphere) and held for 60 minutes. Thereafter, the temperature is maintained and the atmosphere is switched to a clean air atmosphere. In clean air, oxygen is stored in the sample. Oxygen is released in the H 2 —Ar gas atmosphere. In this process, the weight of the sample is measured. Sample weight changes correspond to oxygen storage and release. The change in the weight of the sample is defined as the molar amount of oxygen absorbed per unit weight OSC (μmol-O 2 · g −1 ). Further, δ of Ce 0.5 Zr 0.5 O 2- δ was calculated from the OSC immediately before switching the atmosphere from the H 2 —Ar gas atmosphere to the clean air atmosphere. The theoretical maximum value of δ is 0.25.
　図５（ａ）は、各サンプルのＯＳＣの測定結果を示す図であり、図５（ｂ）は各サンプルにおけるδを示す図である。ｔ´－ＣＺ５５およびκ－ＣＺ５５は、固相反応法を用い作製したそれぞれｔ´相のＣｅ０．５Ｚｒ０．５Ｏ２およびκ相のＣｅ０．５Ｚｒ０．５Ｏ２である。ｔ´－ＣＺ５５（ｐｅｃｈｉｎｉ）はＰｅｃｈｉｎｉ法で作製したｔ´相のＣｅ０．５Ｚｒ０．５Ｏ２である。 FIG. 5A is a diagram showing the OSC measurement result of each sample, and FIG. 5B is a diagram showing δ in each sample. t'-CZ55 and κ-CZ55 is Ce 0.5 Zr 0.5 O 2 of the solid phase each reaction method to prepare using t'-phase of Ce 0.5 Zr 0.5 O 2 and kappa phases. t′-CZ55 (pechini) is Ce 0.5 Zr 0.5 O 2 of the t ′ phase produced by the Pechini method.
　図５（ａ）および図５（ｂ）に示すように、サンプルｔ´－ＣＺ５５、κ－ＣＺ５５およびｔ´－ＣＺ５５（ｐｅｃｈｉｎｉ）ではＯＳＣが低く、δも０．０１程度と小さい。このδは理論的最大値の１０％以下である。一方、サンプルＣＺ５５－ＭＦＯおよびＣＺ５５－ＣＦＯでは、ＯＳＣが高く、δは理論的最大値の５０％程度である。 As shown in FIGS. 5A and 5B, samples t′-CZ55, κ-CZ55 and t′-CZ55 (pechini) have low OSC and δ is as small as about 0.01. This δ is 10% or less of the theoretical maximum value. On the other hand, samples CZ55-MFO and CZ55-CFO have high OSC, and δ is about 50% of the theoretical maximum value.
　表４は、ＣＺ５５－ＭＦＯおよびＣＺ５５－ＣＦＯにおけるサンプル中のスピネル型金属酸化物のモル比およびＣＺ５５相中の酸素に対するスピネル型金属酸化物相の酸素の比を示す表である。
Figure JPOXMLDOC01-appb-T000004
 Table 4 is a table showing the molar ratio of the spinel metal oxide in the sample in CZ55-MFO and CZ55-CFO and the ratio of the oxygen in the spinel metal oxide phase to the oxygen in the CZ55 phase.
Figure JPOXMLDOC01-appb-T000004
　表４のように、スピネル型金属酸化物の組成が１５体積％では、サンプル中のスピネル型金属酸化物のモル比は０．１以下である。さらに、ＣＺ５５相に対するスピネル型金属酸化物相内の酸素の量は０．２以下である。よって、仮にスピネル型金属酸化物相内の酸素がＯＳＣに寄与したとしても、図５（ａ）および図５（ｂ）の大きなＯＳＣは説明できない。よって、図５（ａ）および図５（ｂ）における、ＯＳＣの増大は、スピネル型金属酸化物が電子の伝導に寄与したためと考えられる。このように、スピネル型金属酸化物を用いることで電子伝導性を向上でき、４００℃という低温においてＯＳＣを大きく向上させることができる。 As shown in Table 4, when the composition of the spinel metal oxide is 15% by volume, the molar ratio of the spinel metal oxide in the sample is 0.1 or less. Furthermore, the amount of oxygen in the spinel metal oxide phase relative to the CZ55 phase is 0.2 or less. Therefore, even if oxygen in the spinel-type metal oxide phase contributes to OSC, the large OSC in FIGS. 5A and 5B cannot be explained. Therefore, the increase in OSC in FIGS. 5A and 5B is considered to be because the spinel metal oxide contributed to the conduction of electrons. Thus, by using a spinel metal oxide, the electron conductivity can be improved, and the OSC can be greatly improved at a low temperature of 400 ° C.
　次に４００℃におけるＯＳＣサイクル特性を測定した。クリーン空気雰囲気とＨ２－Ａｒガス雰囲気を３０分毎に切り替えた。図６は、ＯＳＣサイクル特性を示す図である。図６に示すように、サイクルを繰り返すと酸素吸蔵後にＯＳＣが多少低くなるものの、優れたサイクル特性を得ることができる。また、各サイクル後の酸素放出後のＯＳＣはほとんど変わらない。これにより、このサンプルは酸素放出剤として特に優れている。 Next, OSC cycle characteristics at 400 ° C. were measured. The clean air atmosphere and the H 2 —Ar gas atmosphere were switched every 30 minutes. FIG. 6 is a diagram showing the OSC cycle characteristics. As shown in FIG. 6, when the cycle is repeated, although the OSC becomes somewhat lower after oxygen storage, excellent cycle characteristics can be obtained. Also, the OSC after oxygen release after each cycle is almost unchanged. This makes this sample particularly excellent as an oxygen release agent.
　図７（ａ）および図７（ｂ）は、１５０℃におけるＯＳＣを示す図である。図７（ａ）に示すように、ＣＺ５５－ＭＦＯにおいて酸素吸蔵前後のＯＳＣは１１．２μｍｏｌ－Ｏ２・ｇ－１である。図７（ｂ）に示すように、ＣＺ５５－ＣＦＯにおいてＯＳＣは７．６μｍｏｌ－Ｏ２・ｇ－１である。ＯＳＣは、クリーン空気雰囲気への切り替え直前と切り替え後３０分後のＯＳＣ差とした。このように、１５０℃においても酸素吸蔵および放出を確認した。 FIG. 7A and FIG. 7B are diagrams showing OSC at 150.degree. As shown in FIG. 7A, the OSC before and after oxygen storage in CZ55-MFO is 11.2 μmol-O 2 · g −1 . As shown in FIG. 7B, OSC is 7.6 μmol-O 2 · g −1 in CZ55-CFO. OSC was defined as the OSC difference immediately before switching to a clean air atmosphere and 30 minutes after switching. Thus, oxygen storage and release were confirmed even at 150 ° C.
　実施例１のように、Ｃｅ０．５Ｚｒ０．５Ｏ２－δとＭｎＦｅ２Ｏ４との混合酸化物、およびＣｅ０．５Ｚｒ０．５Ｏ２－δとＣｏＦｅ２Ｏ４との混合酸化物は優れたＯＳＣ特性を有することがわかった。 As in Example 1, a mixed oxide of Ce 0.5 Zr 0.5 O 2-δ and MnFe 2 O 4 and a combination of Ce 0.5 Zr 0.5 O 2-δ and CoFe 2 O 4 The mixed oxide was found to have excellent OSC characteristics.
　ＣＺ５５－ＣＦＯについて、ＣｏＦｅ２Ｏ４（ＣＦＯ）の含有量［体積％］を変えたサンプルを作製した。サンプルの作製方法は実施例１と同じである。各サンプルについて４００℃においてＯＳＣを評価した。ＯＳＣの評価方法は実施例１と同じである。 For CZ55-CFO, samples in which the content [volume%] of CoFe 2 O 4 (CFO) was changed were produced. The sample preparation method is the same as in Example 1. OSC was evaluated at 400 ° C. for each sample. The OSC evaluation method is the same as in Example 1.
　表５は、各サンプルのＯＳＣの測定および算出結果を示す表である。
Figure JPOXMLDOC01-appb-T000005
 Table 5 is a table showing the OSC measurement and calculation results of each sample.
Figure JPOXMLDOC01-appb-T000005
　図８は、ＣｏＦｅ２Ｏ４の含有量に対するＯＳＣを示す図である。各ドットが測定した値または算出した値であり、直線はドットをつなぐ線である。表５および図８において、データＡは、ＣＺ５５－ＣＦＯの各サンプルの実際に測定したＯＳＣである。データＡは、ＣｏＦｅ２Ｏ４の含有量が大きくなると大きくなる。 FIG. 8 is a diagram showing OSC with respect to the content of CoFe 2 O 4 . Each dot is a measured value or a calculated value, and a straight line is a line connecting dots. In Table 5 and FIG. 8, data A is the OSC actually measured for each sample of CZ55-CFO. Data A increases as the content of CoFe 2 O 4 increases.
　表５および図８において、データＢは、Ｃｅ０．５Ｚｒ０．５Ｏ２－δのみから酸素が放出されるとしたときのＯＳＣの理論的最大値である。含有量が大きくなるとデータＢが減少するのは、含有量が大きくなるとサンプル内のＣｅ０．５Ｚｒ０．５Ｏ２－δの絶対量が減少するためである。 In Table 5 and FIG. 8, data B is the theoretical maximum value of OSC when oxygen is released only from Ce 0.5 Zr 0.5 O 2-δ . The reason why the data B decreases as the content increases is that the absolute amount of Ce 0.5 Zr 0.5 O 2-δ in the sample decreases as the content increases.
　含有量が約３０体積％以上でデータＡがデータＢを越えている。これは、Ｃｅ０．５Ｚｒ０．５Ｏ２－δに加えＣｏＦｅ２Ｏ４から酸素が放出されるためである。４００℃におけるＣｏＦｅ２Ｏ４が１００％のサンプルのＯＳＣを測定すると、１８７８μｍｏｌ－Ｏ２・ｇ－１である。ＣｏＦｅ２Ｏ４のＯＳＣが大きいのは、ＣｏＦｅ２Ｏ４が４００℃でＣｏＯまたはＦｅＯに還元され、さらにＣｏＯまたはＦｅＯの一部が金属のＣｏおよびＦｅまで還元されるためである。 The content is about 30% by volume or more, and the data A exceeds the data B. This is because oxygen is released from CoFe 2 O 4 in addition to Ce 0.5 Zr 0.5 O 2-δ . When the OSC of a sample having 100% CoFe 2 O 4 at 400 ° C. is measured, it is 1878 μmol-O 2 · g −1 . The reason why the OSC of CoFe 2 O 4 is large is that CoFe 2 O 4 is reduced to CoO or FeO at 400 ° C., and part of CoO or FeO is further reduced to the metals Co and Fe.
　データＡからは、ＣｏＦｅ２Ｏ４の含有量が大きい方がよいように考えられる。しかし、酸素の吸蔵および放出によりＣｏＦｅ２Ｏ４が酸化および還元を繰り返すと、ＣｏＦｅ２Ｏ４が酸化物と金属とを繰り返すことになる。これにより、ＣｏＦｅ２Ｏ４が凝集し作動しなくなる。つまり耐久性がなくなる。実施形態１で説明したように、Ｃｅ１－ｘＺｒｘＯ２－δにＭＦｅ２Ｏ４を添加するのは、混合酸化物内での電子の伝導性を高めることにより、Ｃｅ０．５Ｚｒ０．５Ｏ２－δからの酸素の放出を促進させるためである。ＣｏＦｅ２Ｏ４がＣｅ０．５Ｚｒ０．５Ｏ２－δからの酸素の放出を促進させるのであれば、ＣｏＦｅ２Ｏ４の酸化還元は少なく耐久性は向上する。 From the data A, it is considered that the larger content of CoFe 2 O 4 is better. However, when the CoFe 2 O 4 by insertion of oxygen and release are repeated oxidation and reduction, CoFe 2 O 4 is to repeat the oxide and the metal. Thereby, CoFe 2 O 4 aggregates and does not operate. In other words, durability is lost. As described in the first embodiment, MFe 2 O 4 is added to Ce 1-x Zr x O 2-δ by increasing the conductivity of electrons in the mixed oxide, thereby increasing Ce 0.5 Zr. This is because oxygen release from 0.5 O 2-δ is promoted. If CoFe 2 O 4 promotes the release of oxygen from Ce 0.5 Zr 0.5 O 2-δ , the oxidation and reduction of CoFe 2 O 4 is less and the durability is improved.
　そこで、各サンプルの含有量から各サンプルに含まれるＣｏＦｅ２Ｏ４から放出される酸素量を算出した。ＣｏＦｅ２Ｏ４が１００％のサンプルの酸素放出量（すなわちＯＳＣ）は１８７８μｍｏｌ－Ｏ２・ｇ－１であり、この値にＣｏＦｅ２Ｏ４の比率を乗ずれば各サンプルのＣｏＦｅ２Ｏ４から放出される酸素量が算出できる。各サンプルのデータＡから算出したＣｏＦｅ２Ｏ４から放出される酸素量を引くと、各サンプルにおけるＣｅ０．５Ｚｒ０．５Ｏ２－δからの酸素放出量が算出できる。表５および図８において、データＣは、このようにして算出したＣｅ０．５Ｚｒ０．５Ｏ２－δからの酸素放出量である。表３のデータＲは、データＣ／データＡの比率である。データＲは、各サンプル実測したＯＳＣ（データＡ）のうちＣｅ０．５Ｚｒ０．５Ｏ２－δからの酸素放出量（データＣ）の比率を表している。 Therefore, the amount of oxygen released from CoFe 2 O 4 contained in each sample was calculated from the content of each sample. Oxygen release amount of the sample CoFe 2 O 4 is 100% (i.e. OSC) is 1878μmol-O 2 · g -1, a CoFe 2 O 4 in each sample if Jozure the ratio of CoFe 2 O 4 to the value The amount of oxygen released can be calculated. By subtracting the amount of oxygen released from CoFe 2 O 4 calculated from the data A of each sample, the amount of oxygen released from Ce 0.5 Zr 0.5 O 2-δ in each sample can be calculated. In Table 5 and FIG. 8, data C is the amount of oxygen released from Ce 0.5 Zr 0.5 O 2-δ calculated in this way. Data R in Table 3 is the ratio of data C / data A. Data R represents the ratio of the oxygen release amount (data C) from Ce 0.5 Zr 0.5 O 2-δ in the OSC (data A) measured for each sample.
　表５および図８におけるデータＤは、ＣｏＦｅ２Ｏ４が寄与しないときのＣｅ０．５Ｚｒ０．５Ｏ２－δからの酸素放出量の予測値である。データＤは、含有量が０のときのデータＡである５７．７μｍｏｌ－Ｏ２・ｇ－１と含有量とから算出した。表５および図８におけるデータＣ－ＤはデータＣからデータＤを引いた値である。データＣ－Ｄは、ＣｏＦｅ２Ｏ４がＣＺ５５－ＣＦＯ内の電子の伝導性を高めたことにより、Ｃｅ０．５Ｚｒ０．５Ｏ２－δからの酸素放出量が増加した分に相当する。 Data D in Table 5 and FIG. 8 are predicted values of the amount of oxygen released from Ce 0.5 Zr 0.5 O 2-δ when CoFe 2 O 4 does not contribute. Data D was calculated from 57.7 μmol-O 2 · g −1 , which is data A when the content was 0, and the content. Data CD in Table 5 and FIG. 8 is a value obtained by subtracting data D from data C. Data CD corresponds to the increase in the amount of oxygen released from Ce 0.5 Zr 0.5 O 2-δ due to CoFe 2 O 4 increasing the conductivity of electrons in CZ55-CFO. .
　表５および図８から、含有量が５体積％のときデータＣ－Ｄは最も大きく、含有量が５体積％から大きくなるとデータＣ－Ｄは小さくなる。また、含有量が大きくなるとデータＲが小さくなる。データＲが小さくなるとＣｏＦｅ２Ｏ４からの酸素放出量が増えることを示している。 From Table 5 and FIG. 8, the data CD is the largest when the content is 5% by volume, and the data CD becomes smaller when the content is increased from 5% by volume. Further, the data R decreases as the content increases. It shows that the amount of oxygen released from CoFe 2 O 4 increases as the data R decreases.
　ＣｏＦｅ２Ｏ４がＣｅ０．５Ｚｒ０．５Ｏ２－δからの酸素の放出を促進させるという観点からはデータＣ－Ｄが大きい方が好ましい。データＲが小さくなるとＣｏＦｅ２Ｏ４が酸素の吸蔵放出に寄与することになり耐久性が劣化する可能性がある。 From the viewpoint that CoFe 2 O 4 promotes the release of oxygen from Ce 0.5 Zr 0.5 O 2-δ, it is preferable that the data CD is large. When the data R is small, CoFe 2 O 4 contributes to the occlusion and release of oxygen, and durability may deteriorate.
　データＲを５０％以上としかつデータＣ－Ｄを大きくするため、ＣｏＦｅ２Ｏ４の含有量は１５体積％以下が好ましい。データＲを７０％以上としかつデータＣ－Ｄをより大きくするため、ＣｏＦｅ２Ｏ４の含有量は１０体積％以下がより好ましい。 In order to make the data R 50% or more and increase the data CD, the content of CoFe 2 O 4 is preferably 15% by volume or less. In order to make the data R 70% or more and increase the data CD, the content of CoFe 2 O 4 is more preferably 10% by volume or less.
　実施例２では、ＭＦｅ２Ｏ４の例としてＣｏＦｅ２Ｏ４を用い実験したが、Ｍが２価をとる金属元素であれば、Ｍは還元性がある。よって、より一般的なＭＦｅ２Ｏ４を用いても実施例２と同様の結果となると考えられる。よって、酸化物がＣｅ１－ｘＺｒｘＯ２－δとＭＦｅ２Ｏ４とからなるとき、ＭＦｅ２Ｏ４の含有量は１５体積％以下が好ましく、１０体積％以下がより好ましく、７体積％以下がさらに好ましい。ＭＦｅ２Ｏ４の含有量は、１体積％以上が好ましく、２体積％以上がより好ましい。 In Example 2, an experiment was performed using CoFe 2 O 4 as an example of MFe 2 O 4. However, if M is a divalent metal element, M is reducible. Therefore, it is considered that the same result as in Example 2 is obtained even when more general MFe 2 O 4 is used. Therefore, when the oxide is composed of Ce 1-x Zr x O 2-δ and MFe 2 O 4 , the content of MFe 2 O 4 is preferably 15% by volume or less, more preferably 10% by volume or less, and 7% by volume. % Or less is more preferable. The content of MFe 2 O 4 is preferably 1% by volume or more, and more preferably 2% by volume or more.
　以上、発明の好ましい実施例について詳述したが、本発明は係る特定の実施例に限定されるものではなく、特許請求の範囲に記載された本発明の要旨の範囲内において、種々の変形・変更が可能である。 The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific embodiments, and various modifications and changes can be made within the scope of the gist of the present invention described in the claims. It can be changed.
　１０　混合酸化物
　１２、１４　結晶粒
　１６　層
　２０　サポート材
　２２　酸素貯蔵剤
　２４　触媒金属 10 Mixed oxide 12, 14 Crystal grain 16 Layer 20 Support material 22 Oxygen storage agent 24 Catalytic metal

Claims (10)

  1. 　Ｃｅ１－ｘＺｒｘＯ２－δ（０＜ｘ＜１かつ０≦δ）とスピネル構造を有するＭＦｅ２Ｏ４（Ｍは２価をとる金属元素）とを含むことを特徴とする酸化物。 An oxide comprising Ce 1-x Zr x O 2-δ (0 <x <1 and 0 ≦ δ) and MFe 2 O 4 having a spinel structure (M is a divalent metal element) .
  2. 　前記ＭはＭｎまたはＣｏであることを特徴とする請求項１記載の酸化物。 2. The oxide according to claim 1, wherein said M is Mn or Co.
  3. 　前記ＭＦｅ２Ｏ４の含有量は３３体積％未満であることを特徴とする請求項１または２記載の酸化物。 The oxide according to claim 1 or 2, wherein the content of MFe 2 O 4 is less than 33% by volume.
  4. 　前記酸化物は前記Ｃｅ１－ｘＺｒｘＯ２－δと前記ＭＦｅ２Ｏ４とからなり、前記ＭＦｅ２Ｏ４の含有量は１５体積％以下であることを特徴とする請求項１記載の酸化物。 2. The oxide according to claim 1, wherein the oxide includes the Ce 1-x Zr x O 2-δ and the MFe 2 O 4, and the content of the MFe 2 O 4 is 15% by volume or less. Oxides.
  5. 　前記ＭはＣｏであることを特徴とする請求項４記載の酸化物。 The oxide according to claim 4, wherein said M is Co.
  6. 　Ｃｅ１－ｘＺｒｘＯ２－δ（０＜ｘ＜１、０≦δ）とスピネル構造を有する金属酸化物とを含み、前記Ｃｅ１－ｘＺｒｘＯ２－δの結晶粒の粒界に前記金属酸化物を含む層を備えることを特徴とする酸化物。 Ce 1-x Zr x O 2-δ (0 <x <1, 0 ≦ δ) and a metal oxide having a spinel structure, and the grain boundary of the Ce 1-x Zr x O 2-δ crystal grains An oxide comprising a layer containing the metal oxide.
  7. 　前記金属酸化物を含む層は電子伝導層であることを特徴とする請求項６記載の酸化物。 The oxide according to claim 6, wherein the layer containing the metal oxide is an electron conductive layer.
  8. 　請求項１から７のいずれか一項記載の酸化物を含むことを特徴とする酸素貯蔵剤。 An oxygen storage agent comprising the oxide according to any one of claims 1 to 7.
  9. 　請求項８記載の酸素貯蔵剤を含むことを特徴とする排気ガス用３元触媒。 A three-way catalyst for exhaust gas, comprising the oxygen storage agent according to claim 8.
  10. 　Ｃｅ１－ｘＺｒｘＯ２－δ（０＜ｘ＜１かつ０≦δ）とスピネル構造を有する金属酸化物とを含む酸化物を製造する方法であって、
    　前記Ｃｅ１－ｘＺｒｘＯ２－δと前記金属酸化物とを構成する金属の塩から前記金属の錯体を生成し、前記錯体を含む高分子を生成する工程と、
    　前記高分子を炭化する工程と、
    を含むことを特徴とする酸化物の製造方法。     A method for producing an oxide comprising Ce 1-x Zr x O 2-δ (0 <x <1 and 0 ≦ δ) and a metal oxide having a spinel structure,
    Generating a complex of the metal from a metal salt constituting the Ce 1-x Zr x O 2-δ and the metal oxide, and generating a polymer containing the complex;
    Carbonizing the polymer;
    A method for producing an oxide, comprising:
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Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH01148748A (en) * 1987-12-05 1989-06-12 Mitsubishi Mining & Cement Co Ltd Production of sintered body of zirconia
JP2002292246A (en) * 2001-03-30 2002-10-08 Nissan Diesel Motor Co Ltd Apparatus for cleaning exhaust gas from diesel engine
JP2007145647A (en) * 2005-11-28 2007-06-14 Kyocera Corp Reaction preventing member to lead-containing compound
WO2010010714A1 (en) * 2008-07-23 2010-01-28 新日鉄マテリアルズ株式会社 Oxygen storage material, catalyst for exhaust gas purification, and honeycomb catalyst structure for exhaust gas purification
JP2013199415A (en) * 2012-03-26 2013-10-03 Kyocera Corp Ceramic sintered compact, electronic component mounting substrate using the same, and electronic device
JP2014121686A (en) * 2012-12-21 2014-07-03 Toyota Motor Corp Catalyst for purifying exhaust gas
JP2014128766A (en) * 2012-12-28 2014-07-10 Toyota Motor Corp Catalyst for emission gas purification
JP2014210229A (en) * 2013-04-18 2014-11-13 三井金属鉱業株式会社 Catalyst composition for exhaust gas purification, and catalyst for exhaust gas purification
JP2014226646A (en) * 2013-05-27 2014-12-08 トヨタ自動車株式会社 Exhaust gas purifying catalyst
JP2014237078A (en) * 2013-06-06 2014-12-18 トヨタ自動車株式会社 Exhaust gas purifying catalyst and method for producing the same

Patent Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH01148748A (en) * 1987-12-05 1989-06-12 Mitsubishi Mining & Cement Co Ltd Production of sintered body of zirconia
JP2002292246A (en) * 2001-03-30 2002-10-08 Nissan Diesel Motor Co Ltd Apparatus for cleaning exhaust gas from diesel engine
JP2007145647A (en) * 2005-11-28 2007-06-14 Kyocera Corp Reaction preventing member to lead-containing compound
WO2010010714A1 (en) * 2008-07-23 2010-01-28 新日鉄マテリアルズ株式会社 Oxygen storage material, catalyst for exhaust gas purification, and honeycomb catalyst structure for exhaust gas purification
JP2013199415A (en) * 2012-03-26 2013-10-03 Kyocera Corp Ceramic sintered compact, electronic component mounting substrate using the same, and electronic device
JP2014121686A (en) * 2012-12-21 2014-07-03 Toyota Motor Corp Catalyst for purifying exhaust gas
JP2014128766A (en) * 2012-12-28 2014-07-10 Toyota Motor Corp Catalyst for emission gas purification
JP2014210229A (en) * 2013-04-18 2014-11-13 三井金属鉱業株式会社 Catalyst composition for exhaust gas purification, and catalyst for exhaust gas purification
JP2014226646A (en) * 2013-05-27 2014-12-08 トヨタ自動車株式会社 Exhaust gas purifying catalyst
JP2014237078A (en) * 2013-06-06 2014-12-18 トヨタ自動車株式会社 Exhaust gas purifying catalyst and method for producing the same

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
E. APEL ET AL.: "Introduction to a tough, strong and stable Ce-TZP/MgA1204 composite for biomedical applications", JOURNAL OF THE EUROPEAN CERAMIC SOCIETY, vol. 32, no. 11, August 2012 (2012-08-01), pages 2697 - 2703, XP028512170 *

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