WO2013098987A1 - Carrier for exhaust gas purifying catalysts, exhaust gas purifying catalyst and method for producing same - Google Patents

Carrier for exhaust gas purifying catalysts, exhaust gas purifying catalyst and method for producing same Download PDF

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WO2013098987A1
WO2013098987A1 PCT/JP2011/080384 JP2011080384W WO2013098987A1 WO 2013098987 A1 WO2013098987 A1 WO 2013098987A1 JP 2011080384 W JP2011080384 W JP 2011080384W WO 2013098987 A1 WO2013098987 A1 WO 2013098987A1
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exhaust gas
gas purifying
catalyst
aluminum borate
mass
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PCT/JP2011/080384
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French (fr)
Japanese (ja)
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佐藤　隆広
中原　祐之輔
町田　正人
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三井金属鉱業株式会社
国立大学法人 熊本大学
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Priority to PCT/JP2011/080384 priority Critical patent/WO2013098987A1/en
Publication of WO2013098987A1 publication Critical patent/WO2013098987A1/en

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    • 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]
    • 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
    • B01J23/002—Mixed oxides other than spinels, e.g. perovskite
    • 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
    • B01J23/40—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals of the platinum group metals
    • B01J23/46—Ruthenium, rhodium, osmium or iridium
    • B01J23/464—Rhodium
    • 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
    • B01J23/58—Platinum group metals with alkali- or alkaline earth metals
    • 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
    • B01J35/19—
    • B01J35/30—
    • B01J35/613—
    • B01J35/615—
    • 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
    • B01J37/02—Impregnation, coating or precipitation
    • B01J37/024—Multiple impregnation or coating
    • B01J37/0244—Coatings comprising several layers
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2255/00—Catalysts
    • B01D2255/10—Noble metals or compounds thereof
    • B01D2255/102—Platinum group metals
    • B01D2255/1023—Palladium
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2255/00—Catalysts
    • B01D2255/10—Noble metals or compounds thereof
    • B01D2255/102—Platinum group metals
    • B01D2255/1025—Rhodium
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2255/00—Catalysts
    • B01D2255/20—Metals or compounds thereof
    • B01D2255/204—Alkaline earth metals
    • B01D2255/2042—Barium
    • 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
    • B01D2255/2063—Lanthanum
    • 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
    • B01D2255/2068—Neodymium
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2255/00—Catalysts
    • B01D2255/20—Metals or compounds thereof
    • B01D2255/209—Other metals
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2255/00—Catalysts
    • B01D2255/20—Metals or compounds thereof
    • B01D2255/209—Other metals
    • B01D2255/2092—Aluminium
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2255/00—Catalysts
    • B01D2255/40—Mixed oxides
    • B01D2255/407—Zr-Ce mixed oxides
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2255/00—Catalysts
    • B01D2255/90—Physical characteristics of catalysts
    • B01D2255/902—Multilayered catalyst
    • B01D2255/9022—Two layers
    • 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
    • B01J2523/00—Constitutive chemical elements of heterogeneous catalysts
    • 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 exhaust gas purification catalyst and a method for producing the same, and more specifically, an exhaust gas purification catalyst excellent in exhaust gas purification performance after high-temperature durability and excellent in dispersion of noble metals, particularly Pd, such as automobiles.
  • the present invention relates to a catalyst for purifying harmful components contained in exhaust gas discharged from an internal combustion engine and a method for producing the same.
  • Exhaust gas discharged from an internal combustion engine such as an automobile contains harmful components such as hydrocarbon (HC), carbon monoxide (CO), and nitrogen oxide (NO x ). Therefore, conventionally, a three-way catalyst for purifying and detoxifying these harmful components has been used.
  • HC hydrocarbon
  • CO carbon monoxide
  • NO x nitrogen oxide
  • noble metals such as Pt, Pd, and Rh are used as a catalytic active component, and alumina, ceria, zirconia, a ceria-zirconia composite oxide having oxygen storage ability, and the like are used as a carrier.
  • a catalyst support having a shape such as a honeycomb, a plate, or a pellet made of a ceramic or metal material is used.
  • Patent Documents 1, 2, and 3 There is also an example in which aluminum borate is used as a carrier, and the catalyst component is supported on a green compact including a powdery body that is covered with an aluminum borate whisker and has a hollow portion formed therein. The diffusibility is improved (see Patent Document 4).
  • An object of the present invention is to provide a carrier for an exhaust gas purifying catalyst excellent in exhaust gas purifying performance after high-temperature durability and excellent in dispersibility of noble metals, particularly Pd, an exhaust gas purifying catalyst, and a method for producing the same. It is in.
  • a specific composition of aluminum borate excellent in heat resistance with a ratio of aluminum oxide to boron oxide of 10: 2 to 9: 2 is La 2 O 3 .
  • a modified product is used as a carrier and Pd is supported thereon
  • La-stabilized alumina is used as a carrier and Pd is supported thereon, which is superior in exhaust gas purification performance after high-temperature durability and Pd. It was found that the degree of dispersion was excellent, and the present invention was completed.
  • the support for the exhaust gas purifying catalyst of the present invention is an aluminum oxide and boron oxide modified with La 2 O 3 in an amount of 0.3 to 2% by mass based on the mass of aluminum borate.
  • the ratio of aluminum borate is 10: 2 to 9: 2.
  • aluminum borate having a ratio of aluminum oxide to boron oxide of 10: 2 to 9: 2 is expressed by the formula 10Al 2 O 3 .2B 2 O 3 (5Al 2 O 3 : B 2 O 3 , Al 20 B 4 those represented by O 36), or is intended to include those represented by the formula 9Al 2 O 3 ⁇ 2B 2 O 3 (Al 18 B 4 O 33), hereinafter referred to as a specific composition of aluminum borate , which those modified with La 2 O 3, La 2 O 3 that modified a specific composition of aluminum borate in.
  • the exhaust gas purifying catalyst of the present invention comprises a carrier containing aluminum borate having a specific composition modified with La 2 O 3 in an amount of 0.3 to 2% by mass based on the mass of aluminum borate, And Pd supported on a carrier.
  • the exhaust gas purifying catalyst of the present invention comprises a carrier containing aluminum borate having a specific composition modified with La 2 O 3 in an amount of 0.3 to 2% by mass based on the mass of aluminum borate. And Pd and Ba supported on the carrier.
  • the exhaust gas purifying catalyst component of the present invention includes a catalyst support made of a ceramic or a metal material, and the exhaust gas purifying catalyst layer of the present invention supported on the catalyst support.
  • the exhaust gas purifying catalyst component of the present invention includes a catalyst support made of a ceramic or a metal material, the layer of the exhaust gas purifying catalyst supported on the catalyst support, and the exhaust gas purifying. And a rhodium catalyst layer supported on the catalyst layer.
  • the method for producing an exhaust gas purifying catalyst of the present invention comprises mixing a boric acid with a specific composition and a solution of a lanthanum compound, evaporating to dryness, firing, and boric acid having a specific composition modified with La 2 O 3 Producing aluminum, and then mixing the modified specific composition aluminum borate and Pd compound solution, or mixing the modified specific composition aluminum borate, Ba compound and Pd compound solution And then evaporated to dryness and fired.
  • the carrier for the exhaust gas purifying catalyst of the present invention is excellent in exhaust gas purifying performance after high temperature durability, and is useful for producing an exhaust gas purifying catalyst excellent in precious metal, especially Pd dispersibility
  • the exhaust gas purifying catalyst of the present invention and the exhaust gas purifying catalyst component of the present invention are excellent in exhaust gas purifying performance after high-temperature durability and excellent in the degree of dispersion of Pd, and the production method of the present invention is the present invention. It is suitable for producing an exhaust gas purifying catalyst.
  • FIG. 3 is a diagram showing the measurement results of X-ray diffraction of aluminum borate in Example 1. It is a figure which shows the measurement result of the X-ray diffraction of the aluminum borate of a manufacture example.
  • aluminum borate having a specific composition for use in the present invention have the formula 10Al 2 O 3 ⁇ 2B 2 O 3 (5Al 2 O 3: B 2 O 3, Al 20 B 4 O 36) intended to be displayed in, or formula it is intended to include those represented by 9Al 2 O 3 ⁇ 2B 2 O 3 (Al 18 B 4 O 33).
  • aluminum borate having a specific composition has a cavity having a diameter of about 0.4 nm inside the crystal structure.
  • Such an aluminum borate in an amount of 0.3 to 2% by weight, preferably 0.4 to 2% by weight, more preferably 0.5 to 1.5% by weight, based on the weight of the aluminum borate.
  • the carrier for the exhaust gas purifying catalyst of the present invention can be obtained by modifying with La 2 O 3 .
  • the amount of La 2 O 3 is less than 0.3% by mass or more than 2% by mass based on the mass of aluminum borate, high temperature durability is evident from the examples and comparative examples described later. The degree of improvement in the exhaust gas purification performance of the later catalyst is insufficient.
  • the carrier for the exhaust gas purifying catalyst of the present invention consists only of aluminum borate having a specific composition modified with La 2 O 3
  • the carrier modified with La 2 O 3 is used. It may be a mixture of aluminum borate having a composition and a binder such as alumina commonly used in a three-way catalyst or a support such as CeO 2 —ZrO 2 having an oxygen storage capacity (OSC). That is, the carrier for the exhaust gas purifying catalyst of the present invention contains aluminum borate modified with La 2 O 3 described above.
  • the carrier for the exhaust gas purifying catalyst of the present invention described above can suppress the deterioration rate of the precious metal dispersion after high temperature endurance regardless of any precious metal of Pd, Rh and Pt, and precious metal sintering after high temperature endurance However, the effect is remarkable when the noble metal is Pd.
  • the exhaust gas purifying catalyst of the present invention is a catalyst in which Pd is supported on a carrier containing aluminum borate having a specific composition modified with La 2 O 3 described above.
  • the amount of Pd supported is preferably 0.3 to 3% by mass, more preferably 0.4 to 2% by mass based on the mass of the carrier in terms of the mass of Pd metal.
  • Pd is supported on CeO 2 —ZrO 2 having oxygen storage capacity by supporting Pd on aluminum borate having a specific composition modified with La 2 O 3 as described above, Pd is supported on La-stabilized alumina. Compared with the case where it is made, Pd dispersion degree deterioration rate after high temperature durability is suppressed, and Pd sintering after high temperature durability is suppressed.
  • the exhaust gas purifying catalyst of the present invention is one in which Pd and Ba are supported on a carrier containing aluminum borate having a specific composition modified with La 2 O 3 .
  • Pd and Ba By supporting Pd and Ba, the oxygen dissociation temperature of PdO can be increased, and the catalytic action of Pd can be enhanced.
  • the amount and effect of Pd are as described above.
  • the supported amount of Ba is preferably 2 to 3% by mass, more preferably 2 to 2.5% by mass based on the mass of Pd metal in terms of the mass of BaO.
  • the exhaust gas purifying catalyst structure of the present invention is formed by forming and supporting a layer made of the above-described exhaust gas purifying catalyst of the present invention on a catalyst support made of ceramics or a metal material.
  • the supported amount is preferably 70 to 300 g / L, more preferably 100 to 230 g / L.
  • the shape of the catalyst support made of a ceramic or metal material is not particularly limited, but is generally a shape of a honeycomb, a plate, a pellet, etc. A honeycomb shape is preferred.
  • Examples of the material for such a catalyst support include ceramics such as alumina (Al 2 O 3 ), mullite (3Al 2 O 3 -2SiO 2 ), cordierite (2MgO-2Al 2 O 3 -5SiO 2 ), and the like. And metal materials such as stainless steel.
  • a layer made of the above-described exhaust gas purifying catalyst of the present invention is supported on a catalyst support made of a ceramic or metal material,
  • the Rh catalyst layer is formed on and supported.
  • the shape and material of the catalyst support made of ceramic or metal material in the exhaust gas purifying catalyst component are the same as described above.
  • the amount of Rh supported in the Rh catalyst layer is preferably 0.1 to 0.6% by mass, more preferably 0.1 to 0.4% by mass, based on the mass of the carrier in the Rh catalyst layer.
  • the ratio of Pd: Rh is preferably 3 to 20: 1, more preferably 5 to 20: 1.
  • the loading amount of the lower layer is preferably 70 to 200 g / L, more preferably 100 to 160 g / L, and the loading amount of the upper layer is preferably 30 in consideration of heat resistance, gas diffusibility to the lower layer, exhaust pressure and the like. -100 g / L, more preferably 50-70 g / L.
  • the method for producing an exhaust gas purifying catalyst of the present invention comprises mixing a boric acid with a specific composition and a solution of a lanthanum compound, evaporating to dryness, firing, and boric acid having a specific composition modified with La 2 O 3
  • An aluminum is prepared and then the modified aluminum borate and Pd compound solution are mixed, or the modified aluminum borate, Ba compound and Pd compound solution are mixed and then evaporated to dryness. Solidifying and firing.
  • the solvent constituting the “solution” is not particularly limited as long as it can form a solution, but water is generally used.
  • the aluminum borate having a specific composition used in the method for producing the exhaust gas purifying catalyst of the present invention is commercially available, and can be produced, for example, by the following method on a laboratory scale.
  • 1.5 L of solvent for example, 2-propanol, butanol, ethanol
  • solvent for example, 2-propanol, butanol, ethanol
  • Al alkoxide for example, aluminum ethoxide, aluminum isopropoxide, aluminum, pulverized in an agate mortar
  • Al alkoxide 200 g of triisopropoxide, aluminum n-butoxide, aluminum s-butoxide, aluminum t-butoxide, aluminum tributoxide, aluminum phenoxide, aluminum ethoxyethoxyethoxide
  • alkoxides of B eg, boron n-propoxide, boron trimethyl
  • Siloxide boron ethoxy ethoxide, boron vinyl dimethyl siloxide, boron allyl oxide, boron n-butoxide, boron t-butoxide, boron ethoxide, boron isopro Kishido placed boron methoxide) 40.9 g, and stirred while replacing with N 2 gas.
  • 2-propanol is produced when the aluminum isopropoxide is hydrolyzed. Therefore, it is most preferable to use 2-propanol as a solvent.
  • a mixed solution of solvent for example, 2-propanol
  • the obtained precipitate was washed with ethanol, then washed with pure water, filtered, dried at 120 ° C. overnight (about 15 hours), calcined in air at 300 ° C. for 3 hours, and further in air 1 Calcination at 000 ° C.
  • the aluminum borate can be identified as the aluminum borate of the formula 10Al 2 O 3 ⁇ 2B 2 O 3 by X-ray diffraction.
  • the formula 9Al 2 O 3 ⁇ 2B 2 O 3 (Al 18 B 4 O 33) is present as a standard X-ray diffraction chart, the product of the formula 9Al 2 O 3 ⁇ 2B 2 O 3 (Al 18 B 4 O 33 ) can also be identified.
  • a mixture of aluminum borate having a specific composition and a lanthanum compound (soluble lanthanum compound such as lanthanum nitrate, lanthanum acetate, lanthanum chloride, lanthanum bromide, lanthanum sulfate) is mixed.
  • the aluminum borate-containing slurry and the lanthanum compound solution may be mixed, or aluminum borate may be added to the lanthanum compound solution.
  • the ratio of the amount of aluminum borate to the amount of lanthanum compound at this time is 0.3 to 2% by mass, preferably 0.4 to 2% by mass, more preferably based on the mass of aluminum borate after firing.
  • the amount of La 2 O 3 is 0.5 to 1.5% by mass.
  • the aluminum borate having a specific composition modified with La 2 O 3 obtained as described above is then mixed with a solution of a Pd compound (soluble Pd compound, for example, Pd nitrate, Pd chloride, Pd sulfate).
  • a Pd compound soluble Pd compound, for example, Pd nitrate, Pd chloride, Pd sulfate.
  • an ordinary carrier ordinarily used in the three-way catalyst or a carrier such as CeO 2 —ZrO 2 having an oxygen storage capacity (OSC) can coexist.
  • the ratio of the amount of the carrier and the amount of the Pd compound at this time is such that the amount of Pd supported after calcination is preferably 0.5 to 3% by mass, more preferably 0.7 to 2% by mass.
  • aluminum borate having a specific composition modified with La 2 O 3 obtained as described above is then added to a Ba compound (for example, It is mixed with a solution of barium oxide, barium nitrate, barium acetate, barium oxalate, barium hydroxide, barium carbonate) and a Pd compound (soluble Pd compounds such as Pd nitrate, Pd chloride, Pd sulfate).
  • a Ba compound for example, It is mixed with a solution of barium oxide, barium nitrate, barium acetate, barium oxalate, barium hydroxide, barium carbonate
  • Pd compound soluble Pd compounds such as Pd nitrate, Pd chloride, Pd sulfate
  • the ratio of the amount of the carrier and the amount of the Pd compound at this time is as described above, and the amount of the Ba compound is preferably 2 to 3% by mass, more preferably based on the mass of the Pd metal in terms of the BaO amount. 2 to 2.5% by mass.
  • the Pd compound, or both of the Pd compound and the Ba compound was evaporated to dryness at 120 ° C. overnight (about 15 hours) so that the Pd compound and both of the Ba compound and the Ba compound were almost uniformly attached, and then calcined in air at 600 ° C. for 3 hours.
  • the exhaust gas purifying catalyst of the present invention in which Pd or both of Pd and Ba are supported on aluminum borate having a specific composition modified with La 2 O 3 is obtained.
  • the exhaust gas purifying catalyst component of the present invention can be produced, for example, by the following method.
  • a mixture of aluminum borate having a specific composition modified with La 2 O 3 , a binder, a carrier such as CeO 2 —ZrO 2 having an oxygen storage capacity if necessary, and a Ba compound if necessary with a solution of a Pd compound, and wet-grinding treatment To prepare a slurry.
  • the obtained slurry is applied to a catalyst support made of ceramics or a metal material, preferably a honeycomb-shaped catalyst support, dried and fired according to a known method, and the catalyst support and the catalyst support are coated on the catalyst support.
  • An exhaust gas purifying catalyst structure including an exhaust gas purifying catalyst layer carried on the substrate is obtained.
  • An exhaust gas purifying catalyst structure having an Rh catalyst layer on the catalyst layer can also be produced.
  • the aluminum borate which is a white product.
  • the aluminum borate were identified as aluminum borate of the formula 10Al 2 O 3 ⁇ 2B 2 O 3 by X-ray diffraction. Also, this product is one that can be identified with the formula 9Al 2 O 3 ⁇ 2B 2 O 3 (Al 18 B 4 O 33).
  • Al 1 shows a measurement result of X-ray diffraction of the aluminum borate formula 10Al 2 O 3 ⁇ 2B 2 O 3 (Al 20 B 4 O 36) aluminum borate and formula represented by 9Al 2 O 3 ⁇ 2B
  • the standard card data of aluminum borate represented by 2 O 3 (Al 18 B 4 O 33 ) are shown.
  • the aluminum borate obtained above was immersed in an aqueous lanthanum nitrate solution.
  • the amount of lanthanum nitrate in this aqueous lanthanum nitrate solution is such that the amount of La 2 O 3 in the target aluminum borate modified with La 2 O 3 is 0.5% based on the mass of aluminum borate. It was the quantity used as the mass%. Then, it was evaporated to dryness at 120 ° C. overnight (about 15 hours), and calcined in air at 600 ° C. for 3 hours to obtain aluminum borate having a specific composition modified with 0.5% by mass of La 2 O 3 . .
  • the aluminum borate having a specific composition modified with 0.5% by mass of La 2 O 3 obtained above was immersed in an aqueous solution of Pd nitrate.
  • the amount of Pd nitrate in this aqueous solution of Pd nitrate is an amount that is 0.4% by mass of aluminum borate having a specific composition modified with 0.5% by mass of La 2 O 3 in terms of the mass of Pd metal. there were.
  • it was evaporated to dryness at 120 ° C. overnight (about 15 hours), and calcined in air at 600 ° C. for 3 hours to produce the exhaust gas purifying catalyst of the present invention.
  • Example 2 The amount of lanthanum nitrate in the aqueous solution of lanthanum nitrate, and La 1 wt% amount of La 2 O 3 of the modified specific composition of boric acid in the aluminum based on the weight of aluminum borate in 2 O 3 for the purpose
  • the exhaust gas purifying catalyst of the present invention was produced in the same manner as in Example 1 except that the amount was as follows.
  • Example 3 The amount of lanthanum nitrate in the aqueous solution of lanthanum nitrate, and La 2 wt% amount of La 2 O 3 of the modified specific composition of boric acid in the aluminum based on the weight of aluminum borate in 2 O 3 for the purpose
  • the exhaust gas purifying catalyst of the present invention was produced in the same manner as in Example 1 except that the amount was as follows.
  • Comparative Example 1 Comparative example in the same manner as in Example 1 except that the step of modifying with La 2 O 3 was not performed (that is, Pd was supported on aluminum borate having a specific composition without modification with La 2 O 3 ). An exhaust gas purification catalyst was manufactured.
  • Comparative Example 2 The amount of lanthanum nitrate in the aqueous solution of lanthanum nitrate, and La 3 wt% the amount of La 2 O 3 of the modified specific composition of boric acid in the aluminum based on the weight of aluminum borate in 2 O 3 for the purpose
  • the exhaust gas purifying catalyst of the comparative example was manufactured in the same manner as in Example 1 except that the amount was changed.
  • Comparative Example 3 The amount of lanthanum nitrate in the aqueous solution of lanthanum nitrate, and La 2 O 3 5 wt% amount of La 2 O 3 of the modified specific composition of boric acid in the aluminum based on the weight of aluminum borate in the intended
  • the exhaust gas purifying catalyst of the comparative example was manufactured in the same manner as in Example 1 except that the amount was changed.
  • Comparative Example 4 La-stabilized alumina was immersed in an aqueous Pd nitrate solution.
  • the amount of Pd nitrate in this aqueous solution of Pd nitrate was an amount that would be 0.4% by mass of La stabilized alumina in terms of the mass of Pd metal.
  • the catalyst was evaporated to dryness at 120 ° C. overnight (about 15 hours) and calcined in air at 600 ° C. for 3 hours to produce a comparative exhaust gas purifying catalyst.
  • the outlet gas component was measured using a CO / HC / NO analyzer. From the obtained light-off performance evaluation results, the temperatures (T10, T50, and T90) that reached the NO 10%, 50%, and 90% purification rates were determined. The results were as shown in Table 1.
  • the Pd catalyst using a specific composition of aluminum borate modified with a predetermined amount of La 2 O 3 as a carrier showed excellent catalytic activity after high temperature durability.
  • Example 2 Each exhaust gas purifying catalyst obtained in Example 2 and Comparative Example 4 was endured for 25 hours at 900 ° C., 1000 ° C., 1100 ° C. or 1200 ° C. in an air atmosphere containing 10% of water vapor.
  • the catalytic activity of was evaluated as follows.
  • catalyst powder is set in a reaction tube, CO: 0.51%, NO: 500 ppm, C 3 H 6 : 1170 ppm C, O 2 : 0.4%, from the remaining N 2
  • the outlet gas component was measured using a CO / HC / NO analyzer. From the obtained light-off performance evaluation result, the temperature (T50) at which the NO purification rate reaches 50% was determined. The results were as shown in Table 2.
  • aluminum borate has a lower BET value reduction rate due to endurance treatment than La-stabilized alumina, and aluminum borate has higher heat resistance than La-stabilized alumina. I found it excellent. Moreover, when aluminum borate is modified with 1% by mass of La 2 O 3 , a BET value that is the same as that before the durability treatment is obtained after the durability treatment, and further improvement in heat resistance by modification with La 2 O 3 was recognized.
  • Pd dispersity Pd amount (mole) corresponding to CO adsorption amount / total amount of Pd contained (mole) Is a value calculated by.
  • the Pd dispersion degree deterioration rate was obtained from these values. The results were as shown in Table 4.
  • the degree of precious metal dispersion indirectly represents the level of contact probability with exhaust gas, and it can be said that the higher the degree of precious metal dispersion, the higher the contact efficiency with exhaust gas.
  • aluminum borate modified with Pd / 1% by mass of La 2 O 3 has a reduced Pd dispersity degradation rate, and after high-temperature durability by adopting a high heat-resistant material. Pd sintering is suppressed.
  • Example 4 (Pd monolayer, Pd support concentration 1.3 g / L) It corresponds to 59.8 parts by mass of aluminum borate having a specific composition modified with 1% by mass of La 2 O 3 , 29.6 parts by mass of CeO 2 —ZrO 2 -based composite oxide, and 3.3 parts by mass as barium oxide. An amount of barium nitrate and 6.0 parts by mass of an alumina binder were added to an aqueous solution of Pd nitrate, and wet pulverization was performed to obtain a Pd-containing slurry.
  • the amount of Pd nitrate in this aqueous solution of Pd nitrate was an amount that would be 1.3% by mass in terms of solid content in terms of the mass of Pd metal.
  • the obtained slurry was applied to a ceramic honeycomb (catalyst support) in an amount of 100 g / L, dried and fired to produce an exhaust gas purifying catalyst structure of the present invention.
  • Comparative Example 5 (Pd single layer, Pd support concentration 1.3 g / L) 29.6 parts by mass of CeO 2 —ZrO 2 -based composite oxide, 59.8 parts by mass of La-stabilized alumina, barium nitrate in an amount corresponding to 3.3 parts by mass as barium oxide, and 6.0 parts by mass of an alumina binder It was added to a Pd nitrate aqueous solution and subjected to a wet pulverization treatment to obtain a Pd-containing slurry. The amount of Pd nitrate in this aqueous solution of Pd nitrate was an amount that would be 1.3% by mass in terms of solid content in terms of the mass of Pd metal. The obtained slurry was applied to a ceramic honeycomb (catalyst support) in an amount of 100 g / L, dried and fired to produce a catalyst structure for exhaust gas purification of a comparative example.
  • a ceramic honeycomb catalyst support
  • Example 4 Exhaust gas purification in Example 4 and Comparative Example 5 above was measured using a CO / HC / NO analyzer (Horiba Seisakusho MOTOR EXHAUST GAS ANALYZER MEXA9100). The light-off performance of the catalyst assembly was determined. From the result of the obtained light-off performance evaluation, the temperature (T50) at which 50% purification rate of CO / HC / NO was reached was determined. The results were as shown in Table 5.
  • the amount of Pd nitrate in the aqueous Pd nitrate solution was 0.83% by mass in terms of solid content in terms of the mass of Pd metal.
  • the obtained slurry was applied to a ceramic honeycomb (catalyst support) in an amount of 100 g / L, dried and fired.
  • Nd 2 O 3 —ZrO 2 -based composite oxide 70.3 parts by mass of Nd 2 O 3 —ZrO 2 -based composite oxide, 23.4 parts by mass of La-stabilized alumina, and 6.0 parts by mass of an alumina-based binder were added to the aqueous Rh nitrate solution, and wet pulverization was performed.
  • an Rh-containing slurry was obtained.
  • the amount of nitric acid Rh in the aqueous nitric acid Rh solution was such that the solid content after firing was 0.33% by mass in terms of the mass of Rh metal.
  • the obtained slurry is applied to the Pd-supported ceramic honeycomb obtained above in an amount of 50 g / L, dried and fired to produce the exhaust gas purifying catalyst structure of the present invention consisting of two Pd / Rh layers. did.
  • the amount of Pd nitrate in the aqueous Pd nitrate solution was 0.91% by mass in terms of solid content in terms of the mass of Pd metal.
  • the obtained slurry was applied to a ceramic honeycomb (catalyst support) in an amount of 100 g / L, dried and fired.
  • Nd 2 O 3 —ZrO 2 -based composite oxide 70.4 parts by mass of Nd 2 O 3 —ZrO 2 -based composite oxide, 23.5 parts by mass of La-stabilized alumina, and 6.0 parts by mass of an alumina binder were added to the aqueous Rh nitrate solution, and wet pulverization was performed.
  • an Rh-containing slurry was obtained.
  • the amount of nitric acid Rh in the aqueous nitric acid Rh solution was 0.18% by mass in terms of the solid content after firing in terms of the mass of Rh metal.
  • the obtained slurry is applied to the Pd-supported ceramic honeycomb obtained above in an amount of 50 g / L, dried and fired to produce the exhaust gas purifying catalyst structure of the present invention consisting of two Pd / Rh layers. did.
  • the amount of Pd nitrate in the aqueous Pd nitrate solution was 0.95% by mass in terms of solid content in terms of the mass of Pd metal.
  • the obtained slurry was applied to a ceramic honeycomb (catalyst support) in an amount of 100 g / L, dried and fired.
  • Nd 2 O 3 —ZrO 2 -based composite oxide 70.4 parts by mass of Nd 2 O 3 —ZrO 2 -based composite oxide, 23.5 parts by mass of La-stabilized alumina, and 6.0 parts by mass of an alumina binder were added to the aqueous Rh nitrate solution, and wet pulverization was performed.
  • a slurry containing Rh was obtained.
  • the amount of nitric acid Rh in the aqueous nitric acid Rh solution was an amount that would be 0.10% by mass of the solid content after calcination in terms of the mass of Rh metal.
  • the obtained slurry is applied to the Pd-supported ceramic honeycomb obtained above in an amount of 50 g / L, dried and fired to produce the exhaust gas purifying catalyst structure of the present invention consisting of two Pd / Rh layers. did.
  • Example 8 Pd monolayer, Pd support concentration 1.0 g / L It corresponds to 45.3 parts by mass of aluminum borate having a specific composition modified with 1% by mass of La 2 O 3 , 45.3 parts by mass of CeO 2 —ZrO 2 -based composite oxide, and 2.4 parts by mass as barium oxide.
  • An amount of barium nitrate and 6.0 parts by mass of an alumina binder were added to an aqueous solution of Pd nitrate, and wet pulverization was performed to obtain a Pd-containing slurry.
  • the amount of Pd nitrate in this aqueous solution of Pd nitrate was an amount that would be 1.00% by mass of the solid content in terms of the mass of Pd metal.
  • the obtained slurry was applied to a ceramic honeycomb (catalyst support) in an amount of 100 g / L, dried and fired to produce an exhaust gas purifying catalyst structure of the present invention.
  • Comparative Example 9 (Pd single layer, Pd carrying concentration 1.0 g / L) Exhaust gas purifying catalyst structure of a comparative example in the same manner as in Example 8 except that the same amount of La stabilized alumina was used instead of aluminum borate having a specific composition modified with 1% by mass of La 2 O 3 Manufactured.
  • the outlet gas components at 100 to 500 ° C. were measured using a CO / HC / NO analyzer (MOTOR EXHAUST GAS ANALYZER MEXA9100, manufactured by Horiba, Ltd.).
  • the light-off performance of the exhaust gas purification catalyst components of Examples 6 to 9 was determined.
  • the purification rate ( ⁇ 400) at 400 ° C. of each of CO / HC / NO was determined from the result of the obtained light-off performance evaluation. The results were as shown in Table 6.
  • the purification performance is at the same level as that of the Rh high loading specification, the performance degradation is suppressed, and the aluminum borate having a specific composition modified with La 2 O 3 which is a high heat resistant material is used. A significant reduction in the amount of Rh can be expected by adoption.
  • the obtained precipitate was washed with ethanol, then washed with pure water, and filtered. Then, it dried at 120 degreeC overnight (about 15 hours), baked at 300 degreeC in the air for 3 hours, and also baked at 1,000 degreeC in the air for 5 hours, and obtained the aluminum borate which is a white product.
  • the aluminum borate were identified as aluminum borate of the formula 10Al 2 O 3 ⁇ 2B 2 O 3 by X-ray diffraction. Also, this product is one that can be identified with the formula 9Al 2 O 3 ⁇ 2B 2 O 3 (Al 18 B 4 O 33).
  • the measurement result of the X-ray diffraction of the aluminum borate of this production example the aluminum borate represented by the formula 10Al 2 O 3 .2B 2 O 3 (Al 20 B 4 O 36 ), and the formula 9Al 2 O represents the standard of the card data of aluminum borate represented by 3 ⁇ 2B 2 O 3 (Al 18 B 4 O 33).

Abstract

A carrier which contains an La2O3-modified aluminum borate having a specific composition, said La2O3-modified aluminum borate being obtained by modifying aluminum borate that contains aluminum oxide and boron oxide at a ratio of from 10:2 to 9:2 with La2O3 so that the amount of La2O3 based on the mass of the aluminum borate is 0.3-2% by mass. An exhaust gas purifying catalyst which contains the carrier and Pd or Pd + Ba that are supported by the carrier. A catalyst configuration which contains a catalyst supporting body that is formed of a ceramic or a metal material and a layer of the exhaust gas purifying catalyst, said layer being disposed on the catalyst supporting body. The catalyst configuration may additionally contain an Rh catalyst layer that is disposed on the layer of the exhaust gas purifying catalyst. A method for producing an exhaust gas purifying catalyst.

Description

排気ガス浄化用触媒のための担体、排気ガス浄化用触媒及びその製造方法Carrier for exhaust gas purifying catalyst, exhaust gas purifying catalyst, and method for producing the same
　本発明は排気ガス浄化用触媒及びその製造方法に関し、より詳しくは、高温耐久後の排気ガス浄化性能に優れ、貴金属、特にＰｄの分散度に優れた排気ガス浄化用触媒、例えば、自動車等の内燃機関から排出される排気ガスに含まれる有害成分を浄化する触媒及びその製造方法に関する。 The present invention relates to an exhaust gas purification catalyst and a method for producing the same, and more specifically, an exhaust gas purification catalyst excellent in exhaust gas purification performance after high-temperature durability and excellent in dispersion of noble metals, particularly Pd, such as automobiles. The present invention relates to a catalyst for purifying harmful components contained in exhaust gas discharged from an internal combustion engine and a method for producing the same.
　自動車等の内燃機関から排出される排気ガス中には炭化水素（ＨＣ）、一酸化炭素（ＣＯ）、窒素酸化物（ＮＯＸ）等の有害成分が含まれている。それで、従来から、これらの有害成分を浄化して無害化する三元触媒が用いられている。 Exhaust gas discharged from an internal combustion engine such as an automobile contains harmful components such as hydrocarbon (HC), carbon monoxide (CO), and nitrogen oxide (NO x ). Therefore, conventionally, a three-way catalyst for purifying and detoxifying these harmful components has been used.
　このような三元触媒においては、触媒活性成分としてＰｔ、Ｐｄ、Ｒｈ等の貴金属が用いられており、担体としてアルミナ、セリア、ジルコニアや酸素吸蔵能力を持つセリア－ジルコニア複合酸化物等が用いられており、触媒支持体としてセラミックス又は金属材料からなるハニカム、板、ペレット等の形状のものが用いられている。自動車排気ガスの規制強化に伴い、内燃機関排気ガス浄化用触媒の主要触媒活性成分である貴金属のＰｔ及びＲｈの価格が高騰したことを受け、比較的安価なＰｄを触媒活性成分として利用することにより排気ガス浄化用触媒のコストを削減することが検討され、種々の手段が提案されている（例えば、特許文献１、２、３参照）。また、担体としてホウ酸アルミニウムを用いた例もあり、ホウ酸アルミニウムウィスカーによって外側が覆われその内部に中空部が形成された粉状体を含む圧粉体に触媒成分を担持させることで、ガス拡散性の向上を図っている（特許文献４参照）。 In such a three-way catalyst, noble metals such as Pt, Pd, and Rh are used as a catalytic active component, and alumina, ceria, zirconia, a ceria-zirconia composite oxide having oxygen storage ability, and the like are used as a carrier. As the catalyst support, a catalyst support having a shape such as a honeycomb, a plate, or a pellet made of a ceramic or metal material is used. Use of relatively inexpensive Pd as a catalytic active component in response to the increase in the price of precious metals Pt and Rh, which are the main catalytic active components of internal combustion engine exhaust gas purifying catalysts, in line with the tightening of automobile exhaust gas regulations Thus, it has been studied to reduce the cost of the exhaust gas purifying catalyst, and various means have been proposed (for example, see Patent Documents 1, 2, and 3). There is also an example in which aluminum borate is used as a carrier, and the catalyst component is supported on a green compact including a powdery body that is covered with an aluminum borate whisker and has a hollow portion formed therein. The diffusibility is improved (see Patent Document 4).
特開平０６－０９９０６９号公報Japanese Patent Laid-Open No. 06-099069 特開平０７－１７１３９２号公報Japanese Patent Application Laid-Open No. 07-171392 特開平０８－２８１０７１号公報Japanese Patent Laid-Open No. 08-281071 特開２００２－３７００３５号公報JP 2002-370035 A
　しかしながら、ホウ酸アルミニウムウィスカーは針状であるので比表面積が小さく、それで耐久後の貴金属の凝集が避けられず、耐久性に問題がある。 However, since aluminum borate whiskers are needle-shaped, the specific surface area is small, so that aggregation of precious metals after durability is unavoidable and there is a problem in durability.
　本発明の目的は、高温耐久後の排気ガス浄化性能に優れ、貴金属、特にＰｄの分散度に優れた排気ガス浄化用触媒のための担体、排気ガス浄化用触媒及びその製造方法を提供することにある。 An object of the present invention is to provide a carrier for an exhaust gas purifying catalyst excellent in exhaust gas purifying performance after high-temperature durability and excellent in dispersibility of noble metals, particularly Pd, an exhaust gas purifying catalyst, and a method for producing the same. It is in.
　本発明者らは上記目的を達成するために鋭意検討した結果、酸化アルミニウムと酸化ホウ素の比が１０：２～９：２の耐熱性に優れた特定組成のホウ酸アルミニウムをＬａ２Ｏ３で修飾したものを担体とし、その上にＰｄを担持させると、Ｌａ安定化アルミナを担体とし、その上にＰｄを担持させた場合と比較して高温耐久後の排気ガス浄化性能に優れ、且つＰｄ分散度も優れることを見いだし、本発明を完成した。 As a result of intensive studies to achieve the above object, the present inventors have found that a specific composition of aluminum borate excellent in heat resistance with a ratio of aluminum oxide to boron oxide of 10: 2 to 9: 2 is La 2 O 3 . When a modified product is used as a carrier and Pd is supported thereon, La-stabilized alumina is used as a carrier and Pd is supported thereon, which is superior in exhaust gas purification performance after high-temperature durability and Pd. It was found that the degree of dispersion was excellent, and the present invention was completed.
　即ち、本発明の排気ガス浄化用触媒のための担体は、ホウ酸アルミニウムの質量を基準にして０．３～２質量％となる量のＬａ２Ｏ３で修飾された、酸化アルミニウムと酸化ホウ素の比が１０：２～９：２のホウ酸アルミニウムを含むことを特徴とする。 That is, the support for the exhaust gas purifying catalyst of the present invention is an aluminum oxide and boron oxide modified with La 2 O 3 in an amount of 0.3 to 2% by mass based on the mass of aluminum borate. The ratio of aluminum borate is 10: 2 to 9: 2.
　ここで、酸化アルミニウムと酸化ホウ素の比が１０：２～９：２のホウ酸アルミニウムとは、式１０Ａｌ２Ｏ３・２Ｂ２Ｏ３（５Ａｌ２Ｏ３：Ｂ２Ｏ３、Ａｌ２０Ｂ４Ｏ３６）で表示されるもの、又は式９Ａｌ２Ｏ３・２Ｂ２Ｏ３（Ａｌ１８Ｂ４Ｏ３３）で表示されるものを包含するものであり、以下、特定組成のホウ酸アルミニウムといい、これをＬａ２Ｏ３で修飾したものを、Ｌａ２Ｏ３で修飾した特定組成のホウ酸アルミニウムという。 Here, aluminum borate having a ratio of aluminum oxide to boron oxide of 10: 2 to 9: 2 is expressed by the formula 10Al 2 O 3 .2B 2 O 3 (5Al 2 O 3 : B 2 O 3 , Al 20 B 4 those represented by O 36), or is intended to include those represented by the formula 9Al 2 O 3 · 2B 2 O 3 (Al 18 B 4 O 33), hereinafter referred to as a specific composition of aluminum borate , which those modified with La 2 O 3, La 2 O 3 that modified a specific composition of aluminum borate in.
　本発明の排気ガス浄化用触媒は、ホウ酸アルミニウムの質量を基準にして０．３～２質量％となる量のＬａ２Ｏ３で修飾された特定組成のホウ酸アルミニウムを含む担体と、該担体に担持されたＰｄとを含むことを特徴とする。 The exhaust gas purifying catalyst of the present invention comprises a carrier containing aluminum borate having a specific composition modified with La 2 O 3 in an amount of 0.3 to 2% by mass based on the mass of aluminum borate, And Pd supported on a carrier.
　また、本発明の排気ガス浄化用触媒は、ホウ酸アルミニウムの質量を基準にして０．３～２質量％となる量のＬａ２Ｏ３で修飾された特定組成のホウ酸アルミニウムを含む担体と、該担体に担持されたＰｄ及びＢａとを含むことを特徴とする。 The exhaust gas purifying catalyst of the present invention comprises a carrier containing aluminum borate having a specific composition modified with La 2 O 3 in an amount of 0.3 to 2% by mass based on the mass of aluminum borate. And Pd and Ba supported on the carrier.
　本発明の排気ガス浄化用触媒構成体は、セラミックス又は金属材料からなる触媒支持体と、該触媒支持体上に担持されている上記の本発明の排気ガス浄化用触媒の層とを含むことを特徴とする。 The exhaust gas purifying catalyst component of the present invention includes a catalyst support made of a ceramic or a metal material, and the exhaust gas purifying catalyst layer of the present invention supported on the catalyst support. Features.
　また、本発明の排気ガス浄化用触媒構成体は、セラミックス又は金属材料からなる触媒支持体と、該触媒支持体上に担持されている上記の排気ガス浄化用触媒の層と、該排気ガス浄化用触媒の層の上に担持されているロジウム触媒層とを含むことを特徴とする。 The exhaust gas purifying catalyst component of the present invention includes a catalyst support made of a ceramic or a metal material, the layer of the exhaust gas purifying catalyst supported on the catalyst support, and the exhaust gas purifying. And a rhodium catalyst layer supported on the catalyst layer.
　本発明の排気ガス浄化用触媒の製造方法は、特定組成のホウ酸アルミニウムとランタン化合物の溶液とを混合し、蒸発乾固させ、焼成してＬａ２Ｏ３で修飾された特定組成のホウ酸アルミニウムを製造し、次いで、該修飾された特定組成のホウ酸アルミニウムとＰｄ化合物の溶液とを混合するか、又は該修飾された特定組成のホウ酸アルミニウムとＢａ化合物とＰｄ化合物の溶液とを混合し、その後、蒸発乾固させ、焼成することを特徴とする。 The method for producing an exhaust gas purifying catalyst of the present invention comprises mixing a boric acid with a specific composition and a solution of a lanthanum compound, evaporating to dryness, firing, and boric acid having a specific composition modified with La 2 O 3 Producing aluminum, and then mixing the modified specific composition aluminum borate and Pd compound solution, or mixing the modified specific composition aluminum borate, Ba compound and Pd compound solution And then evaporated to dryness and fired.
　本発明の排気ガス浄化用触媒のための担体は高温耐久後の排気ガス浄化性能に優れ、貴金属、特にＰｄの分散度に優れた排気ガス浄化用触媒を製造するのに有用なものであり、本発明の排気ガス浄化用触媒及び本発明の排気ガス浄化用触媒構成体は高温耐久後の排気ガス浄化性能に優れ、Ｐｄの分散度に優れたものであり、本発明の製造方法は本発明の排気ガス浄化用触媒を製造するのに好適なものである。 The carrier for the exhaust gas purifying catalyst of the present invention is excellent in exhaust gas purifying performance after high temperature durability, and is useful for producing an exhaust gas purifying catalyst excellent in precious metal, especially Pd dispersibility, The exhaust gas purifying catalyst of the present invention and the exhaust gas purifying catalyst component of the present invention are excellent in exhaust gas purifying performance after high-temperature durability and excellent in the degree of dispersion of Pd, and the production method of the present invention is the present invention. It is suitable for producing an exhaust gas purifying catalyst.
実施例１のホウ酸アルミニウムのＸ線回折の測定結果を示す図である。FIG. 3 is a diagram showing the measurement results of X-ray diffraction of aluminum borate in Example 1. 製造例のホウ酸アルミニウムのＸ線回折の測定結果を示す図である。It is a figure which shows the measurement result of the X-ray diffraction of the aluminum borate of a manufacture example.
　本発明で用いる特定組成のホウ酸アルミニウムの特性及びその製造方法は、例えば、Siba　P.　Ray,　“Preparation　and　Characterization　of　Aluminum　Borate”,　J.　Am.　Ceram.　Soc.,75〔9〕,　p2605-2609　(1992)に記載されている。従来は、ホウ酸アルミニウムは化学分析により式９Ａｌ２Ｏ３・２Ｂ２Ｏ３（Ａｌ１８Ｂ４Ｏ３３）で表示されていたが、Martin　等,“Crystal-chemistry　of　mullite-type　aluminoborates　Al１８B４O３３　and　Al５BO９:A　stoichiometry　puzzle”,　Journal　of　Solid　State　Chemistry　184(2011)　70-80には、結晶構造解析によればホウ酸アルミニウムはＡｌ５ＢＯ９（５Ａｌ２Ｏ３：Ｂ２Ｏ３、Ａｌ２０Ｂ４Ｏ３６）、すなわち、式１０Ａｌ２Ｏ３・２Ｂ２Ｏ３で表示されること、ホウ酸アルミニウムに対しては式９Ａｌ２Ｏ３・２Ｂ２Ｏ３（Ａｌ１８Ｂ４Ｏ３３）及びＡｌ５ＢＯ９（５Ａｌ２Ｏ３：Ｂ２Ｏ３、Ａｌ２０Ｂ４Ｏ３６）の両方が許容されること（即ち、同一物質であること）が記載されている。 For example, Siba P. Ray, “Preparation and Characterization of Aluminum Borate”, J. Am. Ceram. Soc., 75 [9], p2605- 2609 (1992). Conventionally, aluminum boric acid had been displayed by the formula 9Al 2 O 3 · 2B 2 O 3 by a chemical analysis (Al 18 B 4 O 33) , Martin , etc., "Crystal-chemistry of mullite- type aluminoborates Al 18 B 4 O 33 and Al 5 BO 9 : A stoichiometry puzzle ”, Journal of Solid State Chemistry 184 (2011) 70-80, according to crystal structure analysis, aluminum borate is Al 5 BO 9 (5Al 2 O 3 : B 2 O 3, Al 20 B 4 O 36), i.e., that represented by formula 10Al 2 O 3 · 2B 2 O 3, relative to the aluminum borate formula 9Al 2 O 3 · 2B 2 O 3 (Al 18 It is described that both B 4 O 33 ) and Al 5 BO 9 (5Al 2 O 3 : B 2 O 3 , Al 20 B 4 O 36 ) are allowed (ie, they are the same substance).
　よって、本発明で用いる特定組成のホウ酸アルミニウムは、式１０Ａｌ２Ｏ３・２Ｂ２Ｏ３（５Ａｌ２Ｏ３：Ｂ２Ｏ３、Ａｌ２０Ｂ４Ｏ３６）で表示されるもの、又は式９Ａｌ２Ｏ３・２Ｂ２Ｏ３（Ａｌ１８Ｂ４Ｏ３３）で表示されるものを包含するものである。 Thus, aluminum borate having a specific composition for use in the present invention have the formula 10Al 2 O 3 · 2B 2 O 3 (5Al 2 O 3: B 2 O 3, Al 20 B 4 O 36) intended to be displayed in, or formula it is intended to include those represented by 9Al 2 O 3 · 2B 2 O 3 (Al 18 B 4 O 33).
　また、特定組成のホウ酸アルミニウムは結晶構造の内部に直径約０．４ｎｍの空洞を持つことが知られている。このようなホウ酸アルミニウムをホウ酸アルミニウムの質量を基準にして０．３～２質量％、好ましくは０．４～２質量％、より好ましくは０．５～１．５質量％となる量のＬａ２Ｏ３で修飾することにより本発明の排気ガス浄化用触媒のための担体が得られる。Ｌａ２Ｏ３の量がホウ酸アルミニウムの質量を基準にして０．３質量％未満であるか、２質量％超である場合には後記の実施例、比較例からも明らかなように高温耐久後の触媒の排気ガス浄化性能の改善程度が不十分である。 In addition, it is known that aluminum borate having a specific composition has a cavity having a diameter of about 0.4 nm inside the crystal structure. Such an aluminum borate in an amount of 0.3 to 2% by weight, preferably 0.4 to 2% by weight, more preferably 0.5 to 1.5% by weight, based on the weight of the aluminum borate. The carrier for the exhaust gas purifying catalyst of the present invention can be obtained by modifying with La 2 O 3 . When the amount of La 2 O 3 is less than 0.3% by mass or more than 2% by mass based on the mass of aluminum borate, high temperature durability is evident from the examples and comparative examples described later. The degree of improvement in the exhaust gas purification performance of the later catalyst is insufficient.
　本発明の排気ガス浄化用触媒のための担体は、上記のＬａ２Ｏ３で修飾された特定組成のホウ酸アルミニウムのみからなるものであっても、上記のＬａ２Ｏ３で修飾された特定組成のホウ酸アルミニウムと三元触媒において普通に使用されているアルミナ等のバインダーや酸素貯蔵能力（ＯＳＣ）を有するＣｅＯ２－ＺｒＯ２等の担体との混合物であってもよい。即ち、本発明の排気ガス浄化用触媒のための担体は上記のＬａ２Ｏ３で修飾されたホウ酸アルミニウムを含むものである。 Even if the carrier for the exhaust gas purifying catalyst of the present invention consists only of aluminum borate having a specific composition modified with La 2 O 3 , the carrier modified with La 2 O 3 is used. It may be a mixture of aluminum borate having a composition and a binder such as alumina commonly used in a three-way catalyst or a support such as CeO 2 —ZrO 2 having an oxygen storage capacity (OSC). That is, the carrier for the exhaust gas purifying catalyst of the present invention contains aluminum borate modified with La 2 O 3 described above.
　上記の本発明の排気ガス浄化用触媒のための担体はＰｄ、Ｒｈ及びＰｔの何れの貴金属を担持させても、高温耐久後の貴金属分散度劣化率が抑えられ、高温耐久後の貴金属シンタリングの抑制が図られるが、貴金属がＰｄである場合に効果は顕著である。 The carrier for the exhaust gas purifying catalyst of the present invention described above can suppress the deterioration rate of the precious metal dispersion after high temperature endurance regardless of any precious metal of Pd, Rh and Pt, and precious metal sintering after high temperature endurance However, the effect is remarkable when the noble metal is Pd.
　本発明の排気ガス浄化用触媒は、上記のＬａ２Ｏ３で修飾された特定組成のホウ酸アルミニウムを含む担体にＰｄを担持させたものである。Ｐｄの担持量はＰｄメタルの質量に換算して担体の質量を基準にして好ましくは０．３～３質量％、より好ましくは０．４～２質量％である。上記のＬａ２Ｏ３で修飾された特定組成のホウ酸アルミニウムにＰｄを担持させることにより、酸素貯蔵能力を有するＣｅＯ２－ＺｒＯ２にＰｄを担持させた場合やＬａ安定化アルミナにＰｄを担持させた場合よりも、高温耐久後のＰｄ分散度劣化率が抑えられ、高温耐久後のＰｄシンタリングの抑制が図られる。 The exhaust gas purifying catalyst of the present invention is a catalyst in which Pd is supported on a carrier containing aluminum borate having a specific composition modified with La 2 O 3 described above. The amount of Pd supported is preferably 0.3 to 3% by mass, more preferably 0.4 to 2% by mass based on the mass of the carrier in terms of the mass of Pd metal. When Pd is supported on CeO 2 —ZrO 2 having oxygen storage capacity by supporting Pd on aluminum borate having a specific composition modified with La 2 O 3 as described above, Pd is supported on La-stabilized alumina. Compared with the case where it is made, Pd dispersion degree deterioration rate after high temperature durability is suppressed, and Pd sintering after high temperature durability is suppressed.
　また、本発明の排気ガス浄化用触媒は、上記のＬａ２Ｏ３で修飾された特定組成のホウ酸アルミニウムを含む担体にＰｄ及びＢａを担持させたものである。Ｐｄ及びＢａを担持させることによりＰｄＯの酸素解離温度を高温化することができ、Ｐｄの触媒作用を高めることができる。Ｐｄの担持量及び効果は上記のとおりである。Ｂａの担持量はＢａＯの質量に換算してＰｄメタルの質量を基準にして好ましくは２～３質量％、より好ましくは２～２．５質量％である。 The exhaust gas purifying catalyst of the present invention is one in which Pd and Ba are supported on a carrier containing aluminum borate having a specific composition modified with La 2 O 3 . By supporting Pd and Ba, the oxygen dissociation temperature of PdO can be increased, and the catalytic action of Pd can be enhanced. The amount and effect of Pd are as described above. The supported amount of Ba is preferably 2 to 3% by mass, more preferably 2 to 2.5% by mass based on the mass of Pd metal in terms of the mass of BaO.
　本発明の排気ガス浄化用触媒構成体は、セラミックス又は金属材料からなる触媒支持体上に上記の本発明の排気ガス浄化用触媒からなる層を形成させ、担持させたものである。その担持量は好ましくは７０～３００ｇ／Ｌ、より好ましくは１００～２３０ｇ／Ｌである。このような排気ガス浄化用触媒構成体においては、セラミックス又は金属材料からなる触媒支持体の形状は、特に限定されるものではないが、一般的にはハニカム、板、ペレット等の形状であり、好ましくはハニカム形状である。また、このような触媒支持体の材質としては、例えば、アルミナ（Ａｌ２Ｏ３）、ムライト（３Ａｌ２Ｏ３－２ＳｉＯ２）、コージェライト（２ＭｇＯ－２Ａｌ２Ｏ３－５ＳｉＯ２）等のセラミックスや、ステンレス等の金属材料を挙げることができる。 The exhaust gas purifying catalyst structure of the present invention is formed by forming and supporting a layer made of the above-described exhaust gas purifying catalyst of the present invention on a catalyst support made of ceramics or a metal material. The supported amount is preferably 70 to 300 g / L, more preferably 100 to 230 g / L. In such an exhaust gas purifying catalyst component, the shape of the catalyst support made of a ceramic or metal material is not particularly limited, but is generally a shape of a honeycomb, a plate, a pellet, etc. A honeycomb shape is preferred. Examples of the material for such a catalyst support include ceramics such as alumina (Al 2 O 3 ), mullite (3Al 2 O 3 -2SiO 2 ), cordierite (2MgO-2Al 2 O 3 -5SiO 2 ), and the like. And metal materials such as stainless steel.
　本発明の排気ガス浄化用触媒構成体のその他の形態は、セラミックス又は金属材料からなる触媒支持体上に上記の本発明の排気ガス浄化用触媒からなる層を担持させた後、その層の上にＲｈ触媒層を形成させ、担持させたものである。このような排気ガス浄化用触媒構成体におけるセラミックス又は金属材料からなる触媒支持体の形状、材質は上記と同じである。Ｒｈ触媒層におけるＲｈの担持量はＲｈ触媒層中の担体の質量を基準にして好ましくは０．１～０．６質量％、より好ましくは０．１～０．４質量％である。この形態の排気ガス浄化用触媒構成体においてはＰｄ：Ｒｈの比は好ましくは３～２０：１、より好ましくは５～２０：１である。また、下層の担持量は好ましくは７０～２００ｇ／Ｌ、より好ましくは１００～１６０ｇ／Ｌであり、上層の担持量は耐熱性、下層へのガス拡散性、排圧等を考慮すると好ましくは３０～１００ｇ／Ｌ、より好ましくは５０～７０ｇ／Ｌである。 In another embodiment of the exhaust gas purifying catalyst structure of the present invention, a layer made of the above-described exhaust gas purifying catalyst of the present invention is supported on a catalyst support made of a ceramic or metal material, The Rh catalyst layer is formed on and supported. The shape and material of the catalyst support made of ceramic or metal material in the exhaust gas purifying catalyst component are the same as described above. The amount of Rh supported in the Rh catalyst layer is preferably 0.1 to 0.6% by mass, more preferably 0.1 to 0.4% by mass, based on the mass of the carrier in the Rh catalyst layer. In this form of exhaust gas purifying catalyst structure, the ratio of Pd: Rh is preferably 3 to 20: 1, more preferably 5 to 20: 1. The loading amount of the lower layer is preferably 70 to 200 g / L, more preferably 100 to 160 g / L, and the loading amount of the upper layer is preferably 30 in consideration of heat resistance, gas diffusibility to the lower layer, exhaust pressure and the like. -100 g / L, more preferably 50-70 g / L.
　本発明の排気ガス浄化用触媒の製造方法は、特定組成のホウ酸アルミニウムとランタン化合物の溶液とを混合し、蒸発乾固させ、焼成してＬａ２Ｏ３で修飾された特定組成のホウ酸アルミニウムを製造し、次いで、該修飾されたホウ酸アルミニウムとＰｄ化合物の溶液とを混合するか、又は該修飾されたホウ酸アルミニウムとＢａ化合物とＰｄ化合物の溶液とを混合し、その後、蒸発乾固させ、焼成することからなる。その処理工程を以下に具体的に説明する。なお、本明細書、請求の範囲等の記載において、「溶液」を構成する溶媒は溶液を形成できるものであれば特には制限されないが、一般的には水が用いられる。 The method for producing an exhaust gas purifying catalyst of the present invention comprises mixing a boric acid with a specific composition and a solution of a lanthanum compound, evaporating to dryness, firing, and boric acid having a specific composition modified with La 2 O 3 An aluminum is prepared and then the modified aluminum borate and Pd compound solution are mixed, or the modified aluminum borate, Ba compound and Pd compound solution are mixed and then evaporated to dryness. Solidifying and firing. The processing steps will be specifically described below. In the description of the present specification, claims, and the like, the solvent constituting the “solution” is not particularly limited as long as it can form a solution, but water is generally used.
　本発明の排気ガス浄化用触媒の製造方法で用いる特定組成のホウ酸アルミニウムは市販されており、また実験室規模では、例えば次の方法で製造することができる。５０℃の湯浴に浸した三口フラスコ中に溶媒（例えば、２－プロパノール、ブタノール、エタノール）１．５Ｌ、瑪瑙乳鉢にて粉砕したＡｌのアルコキシド（例えば、アルミニウムエトキシド、アルミニウムイソプロポキシド、アルミニウムトリイソプロポキシド、アルミニウムｎ－ブトキシド、アルミニウムｓ－ブトキシド、アルミニウムｔ－ブトキシド、アルミニウムトリブトキシド、アルミニウムフェノキシド、アルミニウムエトキシエトキシエトキシド）２００ｇ、及びＢのアルコキシド（例えば、ボロンｎ－プロポキシド、ボロントリメチルシロキシド、ボロンエトキシエトキシド、ボロンビニルジメチルシロキシド、ボロンアルリルオキシド、ボロンｎ－ブトキシド、ボロンｔ－ブトキシド、ボロンエトキシド、ボロンイソプロポキシド、ボロンメトキシド）４０．９ｇを入れ、Ｎ２ガスにて置換しながら攪拌する。Ａｌのアルコキシドとしてアルミニウムイソプロポキシドを用いる場合には、アルミニウムイソプロポキシドが加水分解すると２－プロパノールが生成されるので、溶媒として２－プロパノールを用いることが製造上最も好ましい。Ａｌのアルコキシドが完全に溶解した後、溶媒（例えば、２－プロパノール）：水＝１：１の混合溶液２４．６ｇをゆっくり滴下して徐々に加水分解させると白いゲル状物質が生成する。得られた沈殿物をエタノールで洗浄し、次いで純水で洗浄し、ろ過した後、１２０℃で一晩（約１５時間）乾燥させ、空気中３００℃で３時間焼成した後、更に空気中１，０００℃で５時間焼成して白色生成物であるホウ酸アルミニウムを得る。このホウ酸アルミニウムはＸ線回折によって式１０Ａｌ２Ｏ３・２Ｂ２Ｏ３で表わされるホウ酸アルミニウムであると同定できる。また、Ｘ線回折の標準チャートとして式９Ａｌ２Ｏ３・２Ｂ２Ｏ３（Ａｌ１８Ｂ４Ｏ３３）が存在するが、生成物は、式９Ａｌ２Ｏ３・２Ｂ２Ｏ３（Ａｌ１８Ｂ４Ｏ３３）とも同定できるものである。 The aluminum borate having a specific composition used in the method for producing the exhaust gas purifying catalyst of the present invention is commercially available, and can be produced, for example, by the following method on a laboratory scale. 1.5 L of solvent (for example, 2-propanol, butanol, ethanol) in a three-necked flask immersed in a 50 ° C. water bath, Al alkoxide (for example, aluminum ethoxide, aluminum isopropoxide, aluminum, pulverized in an agate mortar) 200 g of triisopropoxide, aluminum n-butoxide, aluminum s-butoxide, aluminum t-butoxide, aluminum tributoxide, aluminum phenoxide, aluminum ethoxyethoxyethoxide) and alkoxides of B (eg, boron n-propoxide, boron trimethyl) Siloxide, boron ethoxy ethoxide, boron vinyl dimethyl siloxide, boron allyl oxide, boron n-butoxide, boron t-butoxide, boron ethoxide, boron isopro Kishido placed boron methoxide) 40.9 g, and stirred while replacing with N 2 gas. When aluminum isopropoxide is used as the alkoxide of Al, 2-propanol is produced when the aluminum isopropoxide is hydrolyzed. Therefore, it is most preferable to use 2-propanol as a solvent. After the Al alkoxide is completely dissolved, 24.6 g of a mixed solution of solvent (for example, 2-propanol): water = 1: 1 is slowly added dropwise and gradually hydrolyzed to form a white gel substance. The obtained precipitate was washed with ethanol, then washed with pure water, filtered, dried at 120 ° C. overnight (about 15 hours), calcined in air at 300 ° C. for 3 hours, and further in air 1 Calcination at 000 ° C. for 5 hours to obtain aluminum borate as a white product. The aluminum borate can be identified as the aluminum borate of the formula 10Al 2 O 3 · 2B 2 O 3 by X-ray diffraction. Although the formula 9Al 2 O 3 · 2B 2 O 3 (Al 18 B 4 O 33) is present as a standard X-ray diffraction chart, the product of the formula 9Al 2 O 3 · 2B 2 O 3 (Al 18 B 4 O 33 ) can also be identified.
　本発明の排気ガス浄化用触媒の製造方法において特定組成のホウ酸アルミニウムとランタン化合物（可溶性のランタン化合物、例えば硝酸ランタン、酢酸ランタン、塩化ランタン、臭化ランタン、硫酸ランタン）の溶液とを混合する工程は、ホウ酸アルミニウム含有スラリーとランタン化合物の溶液とを混合しても、ランタン化合物の溶液中にホウ酸アルミニウムを添加してもよい。この際のホウ酸アルミニウムの量とランタン化合物の量との比は、焼成後にホウ酸アルミニウムの質量を基準にして０．３～２質量％、好ましくは０．４～２質量％、より好ましくは０．５～１．５質量％のＬａ２Ｏ３となるようにする。 In the method for producing an exhaust gas purifying catalyst of the present invention, a mixture of aluminum borate having a specific composition and a lanthanum compound (soluble lanthanum compound such as lanthanum nitrate, lanthanum acetate, lanthanum chloride, lanthanum bromide, lanthanum sulfate) is mixed. In the step, the aluminum borate-containing slurry and the lanthanum compound solution may be mixed, or aluminum borate may be added to the lanthanum compound solution. The ratio of the amount of aluminum borate to the amount of lanthanum compound at this time is 0.3 to 2% by mass, preferably 0.4 to 2% by mass, more preferably based on the mass of aluminum borate after firing. The amount of La 2 O 3 is 0.5 to 1.5% by mass.
　その後、ランタン化合物がホウ酸アルミニウムの表面にほぼ均一に付着するようにして１２０℃で一晩（約１５時間）蒸発乾固させ、次いで空気中６００℃で３時間焼成して、Ｌａ２Ｏ３で修飾された特定組成のホウ酸アルミニウム、即ち本発明の排気ガス浄化用触媒のための担体を得る。 Then, overnight at 120 ° C. lanthanum compound so as to substantially uniformly adhered to the surface of aluminum borate (about 15 hours) and evaporated to dryness, then calcined 3 hours at 600 ° C. in air, La 2 O 3 To obtain a carrier for the catalyst for purifying exhaust gas of the present invention.
　上記のようにして得られたＬａ２Ｏ３で修飾された特定組成のホウ酸アルミニウムを次いでＰｄ化合物（可溶性のＰｄ化合物、例えば、硝酸Ｐｄ、塩化Ｐｄ、硫酸Ｐｄ）の溶液と混合する。この際、三元触媒において普通に使用されている通常の担体や酸素貯蔵能力（ＯＳＣ）を有するＣｅＯ２－ＺｒＯ２等の担体を共存させることもできる。また、この際の担体の量とＰｄ化合物の量との比は、焼成後にＰｄの担持量が全担体の質量を基準にして好ましくは０．５～３質量％、より好ましくは０．７～２質量％となるようにする。 The aluminum borate having a specific composition modified with La 2 O 3 obtained as described above is then mixed with a solution of a Pd compound (soluble Pd compound, for example, Pd nitrate, Pd chloride, Pd sulfate). At this time, an ordinary carrier ordinarily used in the three-way catalyst or a carrier such as CeO 2 —ZrO 2 having an oxygen storage capacity (OSC) can coexist. Further, the ratio of the amount of the carrier and the amount of the Pd compound at this time is such that the amount of Pd supported after calcination is preferably 0.5 to 3% by mass, more preferably 0.7 to 2% by mass.
　また、Ｐｄ及びＢａが担持された排気ガス浄化用触媒を製造する場合には、上記のようにして得られたＬａ２Ｏ３で修飾された特定組成のホウ酸アルミニウムを次いでＢａ化合物（例えば、酸化バリウム、硝酸バリウム、酢酸バリウム、シュウ酸バリウム、水酸化バリウム、炭酸バリウム）及びＰｄ化合物（可溶性のＰｄ化合物、例えば、硝酸Ｐｄ、塩化Ｐｄ、硫酸Ｐｄ）の溶液と混合する。この際、三元触媒において普通に使用されている通常の担体や酸素貯蔵能力（ＯＳＣ）を有するＣｅＯ２－ＺｒＯ２等の担体を共存させることもできる。この際の担体の量とＰｄ化合物の量との比は上記のとおりにし、Ｂａ化合物の量はＢａＯ量に換算してＰｄメタルの質量を基準にして好ましくは２～３質量％、より好ましくは２～２．５質量％となるようにする。 Further, when producing an exhaust gas purifying catalyst on which Pd and Ba are supported, aluminum borate having a specific composition modified with La 2 O 3 obtained as described above is then added to a Ba compound (for example, It is mixed with a solution of barium oxide, barium nitrate, barium acetate, barium oxalate, barium hydroxide, barium carbonate) and a Pd compound (soluble Pd compounds such as Pd nitrate, Pd chloride, Pd sulfate). At this time, an ordinary carrier ordinarily used in the three-way catalyst or a carrier such as CeO 2 —ZrO 2 having an oxygen storage capacity (OSC) can coexist. The ratio of the amount of the carrier and the amount of the Pd compound at this time is as described above, and the amount of the Ba compound is preferably 2 to 3% by mass, more preferably based on the mass of the Pd metal in terms of the BaO amount. 2 to 2.5% by mass.
　その後、Ｐｄ化合物、又はＰｄ化合物及びＢａ化合物の両方が担体の表面にほぼ均一に付着するようにして１２０℃で一晩（約１５時間）蒸発乾固させ、次いで空気中６００℃で３時間焼成して、Ｌａ２Ｏ３で修飾された特定組成のホウ酸アルミニウムにＰｄ、又はＰｄ及びＢａの両方が担持されている本発明の排気ガス浄化用触媒を得る。 Thereafter, the Pd compound, or both of the Pd compound and the Ba compound, was evaporated to dryness at 120 ° C. overnight (about 15 hours) so that the Pd compound and both of the Ba compound and the Ba compound were almost uniformly attached, and then calcined in air at 600 ° C. for 3 hours. Thus, the exhaust gas purifying catalyst of the present invention in which Pd or both of Pd and Ba are supported on aluminum borate having a specific composition modified with La 2 O 3 is obtained.
　本発明の排気ガス浄化用触媒構成体は、例えば、次の方法によって製造することができる。Ｌａ２Ｏ３で修飾された特定組成のホウ酸アルミニウム、バインダー、所望により酸素貯蔵能力を有するＣｅＯ２－ＺｒＯ２等の担体、及び所望によりＢａ化合物をＰｄ化合物の溶液と混合し、湿式粉砕処理してスラリーを調製する。得られたスラリーを、周知の方法に従って、セラミックス又は金属材料からなる触媒支持体、好ましくはハニカム形状の触媒支持体に塗布し、乾燥させ、焼成して、触媒支持体と、該触媒支持体上に担持されている排気ガス浄化用触媒の層とを含む排気ガス浄化用触媒構成体を得る。この触媒層の上に更にＲｈ触媒層を有する排気ガス浄化用触媒構成体も同様に製造することができる。 The exhaust gas purifying catalyst component of the present invention can be produced, for example, by the following method. A mixture of aluminum borate having a specific composition modified with La 2 O 3 , a binder, a carrier such as CeO 2 —ZrO 2 having an oxygen storage capacity if necessary, and a Ba compound if necessary with a solution of a Pd compound, and wet-grinding treatment To prepare a slurry. The obtained slurry is applied to a catalyst support made of ceramics or a metal material, preferably a honeycomb-shaped catalyst support, dried and fired according to a known method, and the catalyst support and the catalyst support are coated on the catalyst support. An exhaust gas purifying catalyst structure including an exhaust gas purifying catalyst layer carried on the substrate is obtained. An exhaust gas purifying catalyst structure having an Rh catalyst layer on the catalyst layer can also be produced.
　以下に、実施例及び比較例に基づいて本発明を具体的に説明する。 Hereinafter, the present invention will be described in detail based on examples and comparative examples.
　実施例１
　５０℃の湯浴に浸した三口フラスコ中に２－プロパノール１．５Ｌ、瑪瑙乳鉢にて粉砕したアルミニウムイソプロポキシド２００ｇ及びボロンｎ－プロポキシド４０．９ｇを入れ（酸化アルミニウムと酸化ホウ素の比が９：２となる配合）、Ｎ２ガスにて置換しながら攪拌した。アルミニウムイソプロポキシドが完全に溶解した（溶液が透明になった）後、２－プロパノール：水＝１：１の混合溶液２４．６ｇをゆっくり滴下して徐々に加水分解させると白いゲル状物質が生成した。得られた沈殿物をエタノールで洗浄し、次いで純水で洗浄し、ろ過した。その後、１２０℃で一晩（約１５時間）乾燥し、空気中３００℃で３時間焼成し、更に空気中１，０００℃で５時間焼成して白色生成物であるホウ酸アルミニウムを得た。このホウ酸アルミニウムはＸ線回折によって式１０Ａｌ２Ｏ３・２Ｂ２Ｏ３で表わされるホウ酸アルミニウムであると同定できた。また、この生成物は、式９Ａｌ２Ｏ３・２Ｂ２Ｏ３（Ａｌ１８Ｂ４Ｏ３３）とも同定できるものである。 Example 1
In a three-necked flask immersed in a 50 ° C. hot water bath, 1.5 L of 2-propanol, 200 g of aluminum isopropoxide pulverized in an agate mortar and 40.9 g of boron n-propoxide are added (the ratio of aluminum oxide to boron oxide is 9: 2) and stirred while replacing with N 2 gas. After the aluminum isopropoxide is completely dissolved (the solution becomes transparent), 24.6 g of a mixed solution of 2-propanol: water = 1: 1 is slowly dropped and gradually hydrolyzed to form a white gel-like substance. Generated. The obtained precipitate was washed with ethanol, then washed with pure water, and filtered. Then, it dried at 120 degreeC overnight (about 15 hours), baked at 300 degreeC in the air for 3 hours, and also baked at 1,000 degreeC in the air for 5 hours, and obtained the aluminum borate which is a white product. The aluminum borate were identified as aluminum borate of the formula 10Al 2 O 3 · 2B 2 O 3 by X-ray diffraction. Also, this product is one that can be identified with the formula 9Al 2 O 3 · 2B 2 O 3 (Al 18 B 4 O 33).
　図１には、ホウ酸アルミニウムのＸ線回折の測定結果と、式１０Ａｌ２Ｏ３・２Ｂ２Ｏ３（Ａｌ２０Ｂ４Ｏ３６）で表されるホウ酸アルミニウム及び式９Ａｌ２Ｏ３・２Ｂ２Ｏ３（Ａｌ１８Ｂ４Ｏ３３）で表されるホウ酸アルミニウムの標準のカードデータを示す。 1 shows a measurement result of X-ray diffraction of the aluminum borate formula 10Al 2 O 3 · 2B 2 O 3 (Al 20 B 4 O 36) aluminum borate and formula represented by 9Al 2 O 3 · 2B The standard card data of aluminum borate represented by 2 O 3 (Al 18 B 4 O 33 ) are shown.
　上記で得られたホウ酸アルミニウムを硝酸ランタン水溶液中に浸漬させた。この硝酸ランタン水溶液中の硝酸ランタンの量は、目的とするＬａ２Ｏ３で修飾された特定組成のホウ酸アルミニウム中のＬａ２Ｏ３の量がホウ酸アルミニウムの質量を基準にして０．５質量％となる量であった。その後、１２０℃で一晩（約１５時間）蒸発乾固させ、空気中６００℃で３時間焼成して０．５質量％のＬａ２Ｏ３で修飾された特定組成のホウ酸アルミニウムを得た。 The aluminum borate obtained above was immersed in an aqueous lanthanum nitrate solution. The amount of lanthanum nitrate in this aqueous lanthanum nitrate solution is such that the amount of La 2 O 3 in the target aluminum borate modified with La 2 O 3 is 0.5% based on the mass of aluminum borate. It was the quantity used as the mass%. Then, it was evaporated to dryness at 120 ° C. overnight (about 15 hours), and calcined in air at 600 ° C. for 3 hours to obtain aluminum borate having a specific composition modified with 0.5% by mass of La 2 O 3 . .
　次に、上記で得た０．５質量％のＬａ２Ｏ３で修飾された特定組成のホウ酸アルミニウムを硝酸Ｐｄ水溶液中に浸漬させた。この硝酸Ｐｄ水溶液中の硝酸Ｐｄの量はＰｄメタルの質量に換算して、０．５質量％のＬａ２Ｏ３で修飾された特定組成のホウ酸アルミニウムの０．４質量％となる量であった。その後、１２０℃で一晩（約１５時間）蒸発乾固させ、空気中６００℃で３時間焼成して本発明の排気ガス浄化用触媒を製造した。 Next, the aluminum borate having a specific composition modified with 0.5% by mass of La 2 O 3 obtained above was immersed in an aqueous solution of Pd nitrate. The amount of Pd nitrate in this aqueous solution of Pd nitrate is an amount that is 0.4% by mass of aluminum borate having a specific composition modified with 0.5% by mass of La 2 O 3 in terms of the mass of Pd metal. there were. Then, it was evaporated to dryness at 120 ° C. overnight (about 15 hours), and calcined in air at 600 ° C. for 3 hours to produce the exhaust gas purifying catalyst of the present invention.
　実施例２
　硝酸ランタン水溶液中の硝酸ランタンの量を、目的とするＬａ２Ｏ３で修飾された特定組成のホウ酸アルミニウム中のＬａ２Ｏ３の量がホウ酸アルミニウムの質量を基準にして１質量％となる量とした以外は実施例１と同様にして本発明の排気ガス浄化用触媒を製造した。 Example 2
The amount of lanthanum nitrate in the aqueous solution of lanthanum nitrate, and La 1 wt% amount of La 2 O 3 of the modified specific composition of boric acid in the aluminum based on the weight of aluminum borate in 2 O 3 for the purpose The exhaust gas purifying catalyst of the present invention was produced in the same manner as in Example 1 except that the amount was as follows.
　実施例３
　硝酸ランタン水溶液中の硝酸ランタンの量を、目的とするＬａ２Ｏ３で修飾された特定組成のホウ酸アルミニウム中のＬａ２Ｏ３の量がホウ酸アルミニウムの質量を基準にして２質量％となる量とした以外は実施例１と同様にして本発明の排気ガス浄化用触媒を製造した。 Example 3
The amount of lanthanum nitrate in the aqueous solution of lanthanum nitrate, and La 2 wt% amount of La 2 O 3 of the modified specific composition of boric acid in the aluminum based on the weight of aluminum borate in 2 O 3 for the purpose The exhaust gas purifying catalyst of the present invention was produced in the same manner as in Example 1 except that the amount was as follows.
　比較例１
　Ｌａ２Ｏ３で修飾させる工程を実施しなかった以外は実施例１と同様にして（即ち、Ｌａ２Ｏ３で修飾させることなしで特定組成のホウ酸アルミニウムにＰｄを担持させて）比較例の排気ガス浄化用触媒を製造した。 Comparative Example 1
Comparative example in the same manner as in Example 1 except that the step of modifying with La 2 O 3 was not performed (that is, Pd was supported on aluminum borate having a specific composition without modification with La 2 O 3 ). An exhaust gas purification catalyst was manufactured.
　比較例２
　硝酸ランタン水溶液中の硝酸ランタンの量を、目的とするＬａ２Ｏ３で修飾された特定組成のホウ酸アルミニウム中のＬａ２Ｏ３の量がホウ酸アルミニウムの質量を基準にして３質量％となる量とした以外は実施例１と同様にして比較例の排気ガス浄化用触媒を製造した。 Comparative Example 2
The amount of lanthanum nitrate in the aqueous solution of lanthanum nitrate, and La 3 wt% the amount of La 2 O 3 of the modified specific composition of boric acid in the aluminum based on the weight of aluminum borate in 2 O 3 for the purpose The exhaust gas purifying catalyst of the comparative example was manufactured in the same manner as in Example 1 except that the amount was changed.
　比較例３
　硝酸ランタン水溶液中の硝酸ランタンの量を、目的とするＬａ２Ｏ３で修飾された特定組成のホウ酸アルミニウム中のＬａ２Ｏ３の量がホウ酸アルミニウムの質量を基準にして５質量％となる量とした以外は実施例１と同様にして比較例の排気ガス浄化用触媒を製造した。 Comparative Example 3
The amount of lanthanum nitrate in the aqueous solution of lanthanum nitrate, and La 2 O 3 5 wt% amount of La 2 O 3 of the modified specific composition of boric acid in the aluminum based on the weight of aluminum borate in the intended The exhaust gas purifying catalyst of the comparative example was manufactured in the same manner as in Example 1 except that the amount was changed.
　比較例４
　Ｌａ安定化アルミナを硝酸Ｐｄ水溶液中に浸漬させた。この硝酸Ｐｄ水溶液中の硝酸Ｐｄの量はＰｄメタルの質量に換算して、Ｌａ安定化アルミナの０．４質量％となる量であった。その後、１２０℃で一晩（約１５時間）蒸発乾固させ、空気中６００℃で３時間焼成して比較例の排気ガス浄化用触媒を製造した。 Comparative Example 4
La-stabilized alumina was immersed in an aqueous Pd nitrate solution. The amount of Pd nitrate in this aqueous solution of Pd nitrate was an amount that would be 0.4% by mass of La stabilized alumina in terms of the mass of Pd metal. Thereafter, the catalyst was evaporated to dryness at 120 ° C. overnight (about 15 hours) and calcined in air at 600 ° C. for 3 hours to produce a comparative exhaust gas purifying catalyst.
　＜評価＞
　実施例１～３及び比較例１～３で得られた各々の排気ガス浄化用触媒を水蒸気１０％を含んだ大気雰囲気中で、９００℃で２５時間耐久処理した後、それらの触媒活性を以下のようにして評価した。即ち、固定床流通型反応装置を用い、反応管に触媒粉をセットし、ＣＯ：０．５１％、ＮＯ：５００ｐｐｍ、Ｃ３Ｈ６：１１７０ｐｐｍＣ、Ｏ２：０．４％、残余Ｎ２から成る完全燃焼を想定した模擬排気ガスをＷ／Ｆ（触媒質量／ガス流量）＝５．０×１０－４ｇ・ｍｉｎ・ｃｍ－３となるように反応管に流通させ、１００～５００℃における出口ガス成分をＣＯ／ＨＣ／ＮＯ分析計を用いて測定した。得られたライトオフ性能評価結果より、ＮＯの１０％、５０％及び９０％浄化率に到達する温度（Ｔ１０、Ｔ５０及びＴ９０）を求めた。その結果は第１表に示す通りであった。 <Evaluation>
Each exhaust gas purifying catalyst obtained in Examples 1 to 3 and Comparative Examples 1 to 3 was subjected to an endurance treatment at 900 ° C. for 25 hours in an air atmosphere containing 10% of water vapor. It evaluated as follows. That is, using a fixed bed flow type reactor, catalyst powder is set in a reaction tube, CO: 0.51%, NO: 500 ppm, C 3 H 6 : 1170 ppm C, O 2 : 0.4%, from the remaining N 2 The simulated exhaust gas assuming complete combustion is circulated through the reaction tube so that W / F (catalyst mass / gas flow rate) = 5.0 × 10 −4 g · min · cm −3, and at 100 to 500 ° C. The outlet gas component was measured using a CO / HC / NO analyzer. From the obtained light-off performance evaluation results, the temperatures (T10, T50, and T90) that reached the NO 10%, 50%, and 90% purification rates were determined. The results were as shown in Table 1.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
　第１表に示すデータから明らかなように、所定量のＬａ２Ｏ３で修飾された特定組成のホウ酸アルミニウムを担体とするＰｄ触媒は高温耐久後において優れた触媒活性が認められた。 As is apparent from the data shown in Table 1, the Pd catalyst using a specific composition of aluminum borate modified with a predetermined amount of La 2 O 3 as a carrier showed excellent catalytic activity after high temperature durability.
　実施例２及び比較例４で得られた各々の排気ガス浄化用触媒を水蒸気１０％を含んだ大気雰囲気中で、９００℃、１０００℃、１１００℃又は１２００℃で２５時間耐久処理した後、それらの触媒活性を以下のようにして評価した。即ち、固定床流通型反応装置を用い、反応管に触媒粉をセットし、ＣＯ：０．５１％、ＮＯ：５００ｐｐｍ、Ｃ３Ｈ６：１１７０ｐｐｍＣ、Ｏ２：０．４％、残余Ｎ２から成る完全燃焼を想定した模擬排気ガスをＷ／Ｆ（触媒質量／ガス流量）＝５．０×１０－４ｇ・ｍｉｎ・ｃｍ－３となるように反応管に流通させ、１００～５００℃における出口ガス成分をＣＯ／ＨＣ／ＮＯ分析計を用いて測定した。得られたライトオフ性能評価結果より、ＮＯの５０％浄化率に到達する温度（Ｔ５０）を求めた。その結果は第２表に示す通りであった。 Each exhaust gas purifying catalyst obtained in Example 2 and Comparative Example 4 was endured for 25 hours at 900 ° C., 1000 ° C., 1100 ° C. or 1200 ° C. in an air atmosphere containing 10% of water vapor. The catalytic activity of was evaluated as follows. That is, using a fixed bed flow type reactor, catalyst powder is set in a reaction tube, CO: 0.51%, NO: 500 ppm, C 3 H 6 : 1170 ppm C, O 2 : 0.4%, from the remaining N 2 The simulated exhaust gas assuming complete combustion is circulated through the reaction tube so that W / F (catalyst mass / gas flow rate) = 5.0 × 10 −4 g · min · cm −3, and at 100 to 500 ° C. The outlet gas component was measured using a CO / HC / NO analyzer. From the obtained light-off performance evaluation result, the temperature (T50) at which the NO purification rate reaches 50% was determined. The results were as shown in Table 2.
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
　第２表に示すデータから明らかなように、耐久温度が１０００℃を超えると比較例４の触媒は耐久温度の上昇と共にＮＯｘライトオフ性能が低下するのに対して、実施例２の触媒は比較例４の触媒に比べてＮＯｘライトオフ性能の低下が抑えられており、高温での耐久性能に優れる傾向が認められた。 As is apparent from the data shown in Table 2, when the endurance temperature exceeds 1000 ° C., the catalyst of Comparative Example 4 decreases in NOx light-off performance as the endurance temperature increases, whereas the catalyst of Example 2 compares A decrease in NOx light-off performance was suppressed as compared with the catalyst of Example 4, and a tendency to be superior in durability at high temperatures was observed.
　Ｌａ安定化アルミナ、Ｌａ２Ｏ３で修飾されていない特定組成のホウ酸アルミニウム、及び１質量％のＬａ２Ｏ３で修飾された特定組成のホウ酸アルミニウムの各々の担体について、耐久前のＢＥＴ値、水蒸気１０％を含んだ大気雰囲気中で、１０００℃で２５時間耐久処理した後のＢＥＴ値を求めた。また、それらの値から減少率を計算した。それらの結果は第３表に示す通りであった。 For each support of La stabilized alumina, aluminum borate with a specific composition not modified with La 2 O 3 , and aluminum borate with a specific composition modified with 1% by mass of La 2 O 3 , the BET before durability Value, and BET value after endurance treatment at 1000 ° C. for 25 hours in an air atmosphere containing 10% water vapor. The reduction rate was calculated from these values. The results were as shown in Table 3.
Figure JPOXMLDOC01-appb-T000003
Figure JPOXMLDOC01-appb-T000003
　第３表に示すデータから明らかなように、ホウ酸アルミニウムはＬａ安定化アルミナに比べて耐久処理によるＢＥＴ値減少率が抑えられており、ホウ酸アルミニウムはＬａ安定化アルミナに比べて耐熱性に優れることが分かった。また、ホウ酸アルミニウムを１質量％のＬａ２Ｏ３で修飾すると耐久処理後も耐久処理前と変わらないＢＥＴ値が得られており、Ｌａ２Ｏ３で修飾することによる更なる耐熱性の向上が認められた。 As is apparent from the data shown in Table 3, aluminum borate has a lower BET value reduction rate due to endurance treatment than La-stabilized alumina, and aluminum borate has higher heat resistance than La-stabilized alumina. I found it excellent. Moreover, when aluminum borate is modified with 1% by mass of La 2 O 3 , a BET value that is the same as that before the durability treatment is obtained after the durability treatment, and further improvement in heat resistance by modification with La 2 O 3 Was recognized.
　１質量％Ｐｄ／ＣｅＯ２－ＺｒＯ２系複合酸化物（ＯＳＣ材）、１質量％Ｐｄ／Ｌａ安定化アルミナ、及び１質量％Ｐｄ／１質量％のＬａ２Ｏ３で修飾されたホウ酸アルミニウムの各々の触媒について、耐久前のＰｄ分散度、水蒸気１０％を含んだ大気雰囲気中で、１０００℃で２５時間耐久処理した後のＰｄ分散度を公知手段であるＣＯパルス吸着法（T. Takeguchi、S. Manabe、R. Kikuchi、K. Eguchi、T. Kanazawa、S. Matsumoto、Applied Catalysis A：293（2005）91.）に基づいて測定した。このＰｄ分散度は式
　Ｐｄ分散度＝ＣＯ吸着量に相当するＰｄ量(モル)／含まれているＰｄの総量(モル)
により計算される値である。それらの値からＰｄ分散度劣化率を求めた。それらの結果は第４表に示す通りであった。 Aluminum borate modified with 1% by mass Pd / CeO 2 —ZrO 2 -based composite oxide (OSC material), 1% by mass Pd / La stabilized alumina, and 1% by mass Pd / 1% by mass La 2 O 3 For each of the above catalysts, the Pd dispersion before durability, and the Pd dispersion after durability treatment at 1000 ° C. for 25 hours in an air atmosphere containing 10% of water vapor is a known means of CO pulse adsorption method (T. Takeguchi , S. Manabe, R. Kikuchi, K. Eguchi, T. Kanazawa, S. Matsumoto, Applied Catalysis A: 293 (2005) 91.). This Pd dispersity is expressed by the formula Pd dispersity = Pd amount (mole) corresponding to CO adsorption amount / total amount of Pd contained (mole)
Is a value calculated by. The Pd dispersion degree deterioration rate was obtained from these values. The results were as shown in Table 4.
Figure JPOXMLDOC01-appb-T000004
Figure JPOXMLDOC01-appb-T000004
　貴金属分散度は排気ガスとの接触確率の高低を間接的に表しており、貴金属分散度が高い方が排気ガスとの接触効率が高いといえる。第４表に示すデータから明らかなように、Ｐｄ／１質量％のＬａ２Ｏ３で修飾されたホウ酸アルミニウムはＰｄ分散度劣化率が抑えられており高耐熱性材料の採用による高温耐久後のＰｄシンタリング抑制が図られている。 The degree of precious metal dispersion indirectly represents the level of contact probability with exhaust gas, and it can be said that the higher the degree of precious metal dispersion, the higher the contact efficiency with exhaust gas. As is apparent from the data shown in Table 4, aluminum borate modified with Pd / 1% by mass of La 2 O 3 has a reduced Pd dispersity degradation rate, and after high-temperature durability by adopting a high heat-resistant material. Pd sintering is suppressed.
　実施例４（Ｐｄ単層、Ｐｄ担持濃度１．３ｇ／Ｌ）
　１質量％のＬａ２Ｏ３で修飾された特定組成のホウ酸アルミニウム５９．８質量部、ＣｅＯ２－ＺｒＯ２系複合酸化物２９．６質量部、酸化バリウムとして３．３質量部に相当する量の硝酸バリウム及びアルミナ系バインダー６．０質量部を硝酸Ｐｄ水溶液に添加し、湿式粉砕処理を施してＰｄ含有スラリーを得た。この硝酸Ｐｄ水溶液中の硝酸Ｐｄの量はＰｄメタルの質量に換算して、固形分の１．３質量％となる量であった。得られたスラリーをセラミックハニカム（触媒支持体）に１００ｇ／Ｌとなる量で塗布し、乾燥し、焼成して本発明の排気ガス浄化用触媒構成体を製造した。 Example 4 (Pd monolayer, Pd support concentration 1.3 g / L)
It corresponds to 59.8 parts by mass of aluminum borate having a specific composition modified with 1% by mass of La 2 O 3 , 29.6 parts by mass of CeO 2 —ZrO 2 -based composite oxide, and 3.3 parts by mass as barium oxide. An amount of barium nitrate and 6.0 parts by mass of an alumina binder were added to an aqueous solution of Pd nitrate, and wet pulverization was performed to obtain a Pd-containing slurry. The amount of Pd nitrate in this aqueous solution of Pd nitrate was an amount that would be 1.3% by mass in terms of solid content in terms of the mass of Pd metal. The obtained slurry was applied to a ceramic honeycomb (catalyst support) in an amount of 100 g / L, dried and fired to produce an exhaust gas purifying catalyst structure of the present invention.
　比較例５（Ｐｄ単層、Ｐｄ担持濃度１．３ｇ／Ｌ）
　ＣｅＯ２－ＺｒＯ２系複合酸化物２９．６質量部、Ｌａ安定化アルミナ５９．８質量部、酸化バリウムとして３．３質量部に相当する量の硝酸バリウム及びアルミナ系バインダー６．０質量部を硝酸Ｐｄ水溶液に添加し、湿式粉砕処理を施してＰｄ含有スラリーを得た。この硝酸Ｐｄ水溶液中の硝酸Ｐｄの量はＰｄメタルの質量に換算して、固形分の１．３質量％となる量であった。得られたスラリーをセラミックハニカム（触媒支持体）に１００ｇ／Ｌとなる量で塗布し、乾燥し、焼成して比較例の排気ガス浄化用触媒構成体を製造した。 Comparative Example 5 (Pd single layer, Pd support concentration 1.3 g / L)
29.6 parts by mass of CeO 2 —ZrO 2 -based composite oxide, 59.8 parts by mass of La-stabilized alumina, barium nitrate in an amount corresponding to 3.3 parts by mass as barium oxide, and 6.0 parts by mass of an alumina binder It was added to a Pd nitrate aqueous solution and subjected to a wet pulverization treatment to obtain a Pd-containing slurry. The amount of Pd nitrate in this aqueous solution of Pd nitrate was an amount that would be 1.3% by mass in terms of solid content in terms of the mass of Pd metal. The obtained slurry was applied to a ceramic honeycomb (catalyst support) in an amount of 100 g / L, dried and fired to produce a catalyst structure for exhaust gas purification of a comparative example.
　＜評価＞
　上記実施例４、比較例５の排気ガス浄化用触媒構成体を１０００℃に保持した電気炉にセットし、Ｃ３Ｈ６：５，０００ｐｐｍＣ、Ｏ２：０．７５％及び残余量のＮ２から成る完全燃焼を想定した模擬排気ガス（５０ｓ）及び空気（５０ｓ）を周期させながら流通させて２５時間処理した。この模擬排気ガス耐久後の排気ガス浄化用触媒構成体について性能比較を行った。上記と同一組成の完全燃焼を想定した模擬排気ガスを全流量２５Ｌ／ｍｉｎ、ＳＶ＝１００，０００ｈ－１となるように上記の耐久後の実施例４、比較例５の排気ガス浄化用触媒構成体に流通させ、１００～５００℃における出口ガス成分をＣＯ／ＨＣ／ＮＯ分析計（堀場製作所製 MOTOR EXHAUST GAS ANALYZER MEXA9100）を用いて測定して、上記実施例４、比較例５の排気ガス浄化用触媒構成体のライトオフ性能を求めた。得られたライトオフ性能評価の結果より、ＣＯ／ＨＣ／ＮＯそれぞれの５０％浄化率に到達する温度（Ｔ５０）を求めた。その結果は第５表に示す通りであった。 <Evaluation>
The exhaust gas purification catalyst structure of Example 4 and Comparative Example 5 was set in an electric furnace maintained at 1000 ° C., and C 3 H 6 : 5,000 ppmC, O 2 : 0.75%, and the remaining amount of N 2 A simulated exhaust gas (50 s) and air (50 s) assumed to be a complete combustion consisting of were circulated while being cycled for 25 hours. A performance comparison was made on the exhaust gas purifying catalyst structure after endurance of the simulated exhaust gas. Exhaust gas purifying catalyst configurations of Example 4 and Comparative Example 5 after the endurance so that a simulated exhaust gas having the same composition as above is assumed to have a total flow rate of 25 L / min and SV = 100,000 h −1. Exhaust gas purification in Example 4 and Comparative Example 5 above was measured using a CO / HC / NO analyzer (Horiba Seisakusho MOTOR EXHAUST GAS ANALYZER MEXA9100). The light-off performance of the catalyst assembly was determined. From the result of the obtained light-off performance evaluation, the temperature (T50) at which 50% purification rate of CO / HC / NO was reached was determined. The results were as shown in Table 5.
Figure JPOXMLDOC01-appb-T000005
Figure JPOXMLDOC01-appb-T000005
　第５表に示すデータから明らかなように、模擬排気ガス耐久後においても１質量％のＬａ２Ｏ３で修飾された特定組成のホウ酸アルミニウムの方が従来使用されているＬａ安定化アルミナに比べてＣＯ、ＨＣ、ＮＯｘの全てにおいてライトオフ性能に優れていた。 As is apparent from the data shown in Table 5, aluminum borate having a specific composition modified with 1% by mass of La 2 O 3 even after endurance of simulated exhaust gas is used as a conventionally used La-stabilized alumina. Compared to CO, HC, and NOx, the light-off performance was excellent.
　実施例５（下層Ｐｄ、上層Ｒｈの二層触媒、Ｐｄ／Ｒｈ＝５／１、Ｐｄ－Ｒｈ担持濃度１．０ｇ／Ｌ）
　１質量％のＬａ２Ｏ３で修飾された特定組成のホウ酸アルミニウム４５．６質量部、ＣｅＯ２－ＺｒＯ２系複合酸化物４５．６質量部、酸化バリウムとして２．０質量部に相当する量の硝酸バリウム及びアルミナ系バインダー６．０質量部を硝酸Ｐｄ水溶液に添加し、湿式粉砕処理を施してＰｄ含有スラリーを得た。この硝酸Ｐｄ水溶液中の硝酸Ｐｄの量はＰｄメタルの質量に換算して、固形分の０．８３質量％となる量であった。得られたスラリーをセラミックハニカム（触媒支持体）に１００ｇ／Ｌとなる量で塗布し、乾燥し、焼成した。 Example 5 (Lower layer Pd, Upper layer Rh two-layer catalyst, Pd / Rh = 5/1, Pd-Rh loading concentration 1.0 g / L)
This corresponds to 45.6 parts by mass of aluminum borate having a specific composition modified with 1% by mass of La 2 O 3 , 45.6 parts by mass of CeO 2 —ZrO 2 -based composite oxide, and 2.0 parts by mass as barium oxide. An amount of barium nitrate and 6.0 parts by mass of an alumina binder were added to an aqueous solution of Pd nitrate, and wet pulverization was performed to obtain a Pd-containing slurry. The amount of Pd nitrate in the aqueous Pd nitrate solution was 0.83% by mass in terms of solid content in terms of the mass of Pd metal. The obtained slurry was applied to a ceramic honeycomb (catalyst support) in an amount of 100 g / L, dried and fired.
　また、Ｎｄ２Ｏ３－ＺｒＯ２系複合酸化物７０．３質量部、Ｌａ安定化アルミナ２３．４質量部及びアルミナ系バインダー６．０質量部を硝酸Ｒｈ水溶液に添加し、湿式粉砕処理を施してＲｈ含有スラリーを得た。この硝酸Ｒｈ水溶液中の硝酸Ｒｈの量はＲｈメタルの質量に換算して、焼成後の固形分の０．３３質量％となる量であった。得られたスラリーを上記で得られたＰｄ担持セラミックハニカムに５０ｇ／Ｌとなる量で塗布し、乾燥し、焼成してＰｄ／Ｒｈ二層からなる本発明の排気ガス浄化用触媒構成体を製造した。 Further, 70.3 parts by mass of Nd 2 O 3 —ZrO 2 -based composite oxide, 23.4 parts by mass of La-stabilized alumina, and 6.0 parts by mass of an alumina-based binder were added to the aqueous Rh nitrate solution, and wet pulverization was performed. Thus, an Rh-containing slurry was obtained. The amount of nitric acid Rh in the aqueous nitric acid Rh solution was such that the solid content after firing was 0.33% by mass in terms of the mass of Rh metal. The obtained slurry is applied to the Pd-supported ceramic honeycomb obtained above in an amount of 50 g / L, dried and fired to produce the exhaust gas purifying catalyst structure of the present invention consisting of two Pd / Rh layers. did.
　実施例６（下層Ｐｄ、上層Ｒｈの二層触媒、Ｐｄ／Ｒｈ＝１０／１、Ｐｄ－Ｒｈ担持濃度１．０ｇ／Ｌ）
　１質量％のＬａ２Ｏ３で修飾された特定組成のホウ酸アルミニウム４５．４質量部、ＣｅＯ２－ＺｒＯ２系複合酸化物４５．４質量部、酸化バリウムとして２．２質量部に相当する量の硝酸バリウム及びアルミナ系バインダー６．０質量部を硝酸Ｐｄ水溶液に添加し、湿式粉砕処理を施してＰｄ含有スラリーを得た。この硝酸Ｐｄ水溶液中の硝酸Ｐｄの量はＰｄメタルの質量に換算して、固形分の０．９１質量％となる量であった。得られたスラリーをセラミックハニカム（触媒支持体）に１００ｇ／Ｌとなる量で塗布し、乾燥し、焼成した。 Example 6 (Lower layer Pd, upper layer Rh two-layer catalyst, Pd / Rh = 10/1, Pd—Rh supported concentration 1.0 g / L)
It corresponds to 45.4 parts by mass of aluminum borate having a specific composition modified with 1% by mass of La 2 O 3 , 45.4 parts by mass of CeO 2 —ZrO 2 -based composite oxide, and 2.2 parts by mass as barium oxide. An amount of barium nitrate and 6.0 parts by mass of an alumina binder were added to an aqueous solution of Pd nitrate, and wet pulverization was performed to obtain a Pd-containing slurry. The amount of Pd nitrate in the aqueous Pd nitrate solution was 0.91% by mass in terms of solid content in terms of the mass of Pd metal. The obtained slurry was applied to a ceramic honeycomb (catalyst support) in an amount of 100 g / L, dried and fired.
　また、Ｎｄ２Ｏ３－ＺｒＯ２系複合酸化物７０．４質量部、Ｌａ安定化アルミナ２３．５質量部及びアルミナ系バインダー６．０質量部を硝酸Ｒｈ水溶液に添加し、湿式粉砕処理を施してＲｈ含有スラリーを得た。この硝酸Ｒｈ水溶液中の硝酸Ｒｈの量はＲｈメタルの質量に換算して、焼成後の固形分の０．１８質量％となる量であった。得られたスラリーを上記で得られたＰｄ担持セラミックハニカムに５０ｇ／Ｌとなる量で塗布し、乾燥し、焼成してＰｄ／Ｒｈ二層からなる本発明の排気ガス浄化用触媒構成体を製造した。 Further, 70.4 parts by mass of Nd 2 O 3 —ZrO 2 -based composite oxide, 23.5 parts by mass of La-stabilized alumina, and 6.0 parts by mass of an alumina binder were added to the aqueous Rh nitrate solution, and wet pulverization was performed. Thus, an Rh-containing slurry was obtained. The amount of nitric acid Rh in the aqueous nitric acid Rh solution was 0.18% by mass in terms of the solid content after firing in terms of the mass of Rh metal. The obtained slurry is applied to the Pd-supported ceramic honeycomb obtained above in an amount of 50 g / L, dried and fired to produce the exhaust gas purifying catalyst structure of the present invention consisting of two Pd / Rh layers. did.
　実施例７（下層Ｐｄ、上層Ｒｈの二層触媒、Ｐｄ／Ｒｈ＝１９／１、Ｐｄ－Ｒｈ担持濃度１．０ｇ／Ｌ）
　１質量％のＬａ２Ｏ３で修飾された特定組成のホウ酸アルミニウム４５．４質量部、ＣｅＯ２－ＺｒＯ２系複合酸化物４５．４質量部、酸化バリウムとして２．３質量部に相当する量の硝酸バリウム及びアルミナ系バインダー６．０質量部を硝酸Ｐｄ水溶液に添加し、湿式粉砕処理を施してＰｄ含有スラリーを得た。この硝酸Ｐｄ水溶液中の硝酸Ｐｄの量はＰｄメタルの質量に換算して、固形分の０．９５質量％となる量であった。得られたスラリーをセラミックハニカム（触媒支持体）に１００ｇ／Ｌとなる量で塗布し、乾燥し、焼成した。 Example 7 (Lower layer Pd, Upper layer Rh two-layer catalyst, Pd / Rh = 19/1, Pd-Rh supported concentration 1.0 g / L)
It corresponds to 45.4 parts by mass of aluminum borate having a specific composition modified with 1% by mass of La 2 O 3 , 45.4 parts by mass of CeO 2 —ZrO 2 -based composite oxide, and 2.3 parts by mass as barium oxide. An amount of barium nitrate and 6.0 parts by mass of an alumina binder were added to an aqueous solution of Pd nitrate, and wet pulverization was performed to obtain a Pd-containing slurry. The amount of Pd nitrate in the aqueous Pd nitrate solution was 0.95% by mass in terms of solid content in terms of the mass of Pd metal. The obtained slurry was applied to a ceramic honeycomb (catalyst support) in an amount of 100 g / L, dried and fired.
　また、Ｎｄ２Ｏ３－ＺｒＯ２系複合酸化物７０．４質量部、Ｌａ安定化アルミナ２３．５質量部及びアルミナ系バインダー６．０質量部を硝酸Ｒｈ水溶液に添加し、湿式粉砕処理を施してＲｈ含有スラリーを得た。この硝酸Ｒｈ水溶液中の硝酸Ｒｈの量はＲｈメタルの質量に換算して、焼成後の固形分の０．１０質量％となる量であった。得られたスラリーを上記で得られたＰｄ担持セラミックハニカムに５０ｇ／Ｌとなる量で塗布し、乾燥し、焼成してＰｄ／Ｒｈ二層からなる本発明の排気ガス浄化用触媒構成体を製造した。 Further, 70.4 parts by mass of Nd 2 O 3 —ZrO 2 -based composite oxide, 23.5 parts by mass of La-stabilized alumina, and 6.0 parts by mass of an alumina binder were added to the aqueous Rh nitrate solution, and wet pulverization was performed. Thus, a slurry containing Rh was obtained. The amount of nitric acid Rh in the aqueous nitric acid Rh solution was an amount that would be 0.10% by mass of the solid content after calcination in terms of the mass of Rh metal. The obtained slurry is applied to the Pd-supported ceramic honeycomb obtained above in an amount of 50 g / L, dried and fired to produce the exhaust gas purifying catalyst structure of the present invention consisting of two Pd / Rh layers. did.
　実施例８（Ｐｄ単層、Ｐｄ担持濃度１．０ｇ／Ｌ）
　１質量％のＬａ２Ｏ３で修飾された特定組成のホウ酸アルミニウム４５．３質量部、ＣｅＯ２－ＺｒＯ２系複合酸化物４５．３質量部、酸化バリウムとして２．４質量部に相当する量の硝酸バリウム及びアルミナ系バインダー６．０質量部を硝酸Ｐｄ水溶液に添加し、湿式粉砕処理を施してＰｄ含有スラリーを得た。この硝酸Ｐｄ水溶液中の硝酸Ｐｄの量はＰｄメタルの質量に換算して、固形分の１．００質量％となる量であった。得られたスラリーをセラミックハニカム（触媒支持体）に１００ｇ／Ｌとなる量で塗布し、乾燥し、焼成して本発明の排気ガス浄化用触媒構成体を製造した。 Example 8 (Pd monolayer, Pd support concentration 1.0 g / L)
It corresponds to 45.3 parts by mass of aluminum borate having a specific composition modified with 1% by mass of La 2 O 3 , 45.3 parts by mass of CeO 2 —ZrO 2 -based composite oxide, and 2.4 parts by mass as barium oxide. An amount of barium nitrate and 6.0 parts by mass of an alumina binder were added to an aqueous solution of Pd nitrate, and wet pulverization was performed to obtain a Pd-containing slurry. The amount of Pd nitrate in this aqueous solution of Pd nitrate was an amount that would be 1.00% by mass of the solid content in terms of the mass of Pd metal. The obtained slurry was applied to a ceramic honeycomb (catalyst support) in an amount of 100 g / L, dried and fired to produce an exhaust gas purifying catalyst structure of the present invention.
　比較例６（下層Ｐｄ、上層Ｒｈの二層触媒、Ｐｄ／Ｒｈ＝５／１、Ｐｄ－Ｒｈ担持濃度１．０ｇ／Ｌ）
　１質量％のＬａ２Ｏ３で修飾された特定組成のホウ酸アルミニウムの代わりに同量のＬａ安定化アルミナを用いた以外は実施例５と同様にして比較例の排気ガス浄化用触媒構成体を製造した。 Comparative Example 6 (Lower layer Pd, Upper layer Rh two-layer catalyst, Pd / Rh = 5/1, Pd—Rh supported concentration 1.0 g / L)
Exhaust gas purifying catalyst structure of a comparative example in the same manner as in Example 5 except that the same amount of La stabilized alumina was used instead of aluminum borate having a specific composition modified with 1% by mass of La 2 O 3 Manufactured.
　比較例７（下層Ｐｄ、上層Ｒｈの二層触媒、Ｐｄ／Ｒｈ＝１０／１、Ｐｄ－Ｒｈ担持濃度１．０ｇ／Ｌ）
　１質量％のＬａ２Ｏ３で修飾された特定組成のホウ酸アルミニウムの代わりに同量のＬａ安定化アルミナを用いた以外は実施例６と同様にして比較例の排気ガス浄化用触媒構成体を製造した。 Comparative Example 7 (lower layer Pd, upper layer Rh two-layer catalyst, Pd / Rh = 10/1, Pd—Rh loading concentration 1.0 g / L)
Exhaust gas purifying catalyst structure of a comparative example in the same manner as in Example 6 except that the same amount of La stabilized alumina was used instead of aluminum borate having a specific composition modified with 1% by mass of La 2 O 3 Manufactured.
　比較例８（下層Ｐｄ、上層Ｒｈの二層触媒、Ｐｄ／Ｒｈ＝１９／１、Ｐｄ－Ｒｈ担持濃度１．０ｇ／Ｌ）
　１質量％のＬａ２Ｏ３で修飾された特定組成のホウ酸アルミニウムの代わりに同量のＬａ安定化アルミナを用いた以外は実施例７と同様にして比較例の排気ガス浄化用触媒構成体を製造した。 Comparative Example 8 (Lower layer Pd, Upper layer Rh two-layer catalyst, Pd / Rh = 19/1, Pd—Rh supported concentration 1.0 g / L)
Exhaust gas purifying catalyst structure of a comparative example in the same manner as in Example 7 except that the same amount of La stabilized alumina was used instead of aluminum borate having a specific composition modified with 1% by mass of La 2 O 3 Manufactured.
　比較例９（Ｐｄ単層、Ｐｄ担持濃度１．０ｇ／Ｌ）
　１質量％のＬａ２Ｏ３で修飾された特定組成のホウ酸アルミニウムの代わりに同量のＬａ安定化アルミナを用いた以外は実施例８と同様にして比較例の排気ガス浄化用触媒構成体を製造した。 Comparative Example 9 (Pd single layer, Pd carrying concentration 1.0 g / L)
Exhaust gas purifying catalyst structure of a comparative example in the same manner as in Example 8 except that the same amount of La stabilized alumina was used instead of aluminum borate having a specific composition modified with 1% by mass of La 2 O 3 Manufactured.
　＜評価＞
　上記実施例５～８、比較例６～９の排気ガス浄化用触媒構成体を１０００℃に保持した電気炉にセットし、Ｃ３Ｈ６：５，０００ｐｐｍＣ、Ｏ２：０．７５％及び残余量のＮ２から成る完全燃焼を想定した模擬排気ガス（５０ｓ）及び空気（５０ｓ）を周期させながら流通させて２５時間処理した。この模擬排気ガス耐久後の排気ガス浄化用触媒構成体について性能比較を行った。上記と同一組成の完全燃焼を想定した模擬排気ガスを全流量２５Ｌ／ｍｉｎ、ＳＶ＝１００，０００ｈ－１となるように上記の耐久後の実施例５～８、比較例６～９の排気ガス浄化用触媒構成体に流通させ、１００～５００℃における出口ガス成分をＣＯ／ＨＣ／ＮＯ分析計（堀場製作所製 MOTOR EXHAUST GAS ANALYZER MEXA9100）を用いて測定して、上記実施例５～８、比較例６～９の排気ガス浄化用触媒構成体のライトオフ性能を求めた。得られたライトオフ性能評価の結果より、ＣＯ／ＨＣ／ＮＯそれぞれの４００℃における浄化率（η４００）を求めた。その結果は第６表に示す通りであった。 <Evaluation>
The exhaust gas purifying catalyst components of Examples 5 to 8 and Comparative Examples 6 to 9 were set in an electric furnace maintained at 1000 ° C., and C 3 H 6 : 5,000 ppmC, O 2 : 0.75%, and the remainder Simulated exhaust gas (50 s) and air (50 s) consisting of an amount of N 2 assuming complete combustion were circulated while being cycled for 25 hours. A performance comparison was made on the exhaust gas purifying catalyst structure after endurance of the simulated exhaust gas. Exhaust gases of Examples 5 to 8 and Comparative Examples 6 to 9 after the endurance so that the simulated exhaust gas having the same composition as described above is assumed to have a total flow rate of 25 L / min and SV = 100,000 h −1. Compared with Examples 5 to 8 above, the outlet gas components at 100 to 500 ° C. were measured using a CO / HC / NO analyzer (MOTOR EXHAUST GAS ANALYZER MEXA9100, manufactured by Horiba, Ltd.). The light-off performance of the exhaust gas purification catalyst components of Examples 6 to 9 was determined. The purification rate (η400) at 400 ° C. of each of CO / HC / NO was determined from the result of the obtained light-off performance evaluation. The results were as shown in Table 6.
Figure JPOXMLDOC01-appb-T000006
Figure JPOXMLDOC01-appb-T000006
　第６表に示すデータから明らかなように、模擬排気ガス耐久後において、従来使用されているＬａ安定化アルミナ及びＣｅＯ２－ＺｒＯ２系複合酸化物をＰｄの担体として用いると（比較例６～９）、Ｒｈ担持量が０．３３％から０．１０％へと少なくなるに従って浄化性能は低下する傾向にある。一方、１質量％のＬａ２Ｏ３で修飾された特定組成のホウ酸アルミニウム及びＣｅＯ２－ＺｒＯ２系複合酸化物をＰｄの担体として用いると、Ｒｈ担持量が０．３３％から０．１０％へと少なくなっても、浄化性能はＲｈ高担持仕様と同等レベルであり、性能低下が抑えられており、高耐熱性材料であるＬａ２Ｏ３で修飾された特定組成のホウ酸アルミニウムの採用によるＲｈ量の大幅な削減が期待できる。 As is apparent from the data shown in Table 6, after the simulated exhaust gas endurance, conventionally used La-stabilized alumina and CeO 2 —ZrO 2 -based composite oxide were used as Pd carriers (Comparative Examples 6 to 6). 9) Purifying performance tends to decrease as the amount of Rh supported decreases from 0.33% to 0.10%. On the other hand, when an aluminum borate having a specific composition modified with 1% by mass of La 2 O 3 and a CeO 2 —ZrO 2 -based composite oxide are used as a Pd support, the Rh loading is 0.33% to 0.10. %, The purification performance is at the same level as that of the Rh high loading specification, the performance degradation is suppressed, and the aluminum borate having a specific composition modified with La 2 O 3 which is a high heat resistant material is used. A significant reduction in the amount of Rh can be expected by adoption.
　（特定組成のホウ酸アルミニウムの製造例）
　５０℃の湯浴に浸した三口フラスコ中に２－プロパノール１．５Ｌ、瑪瑙乳鉢にて粉砕したアルミニウムイソプロポキシド２２２．２ｇ及びボロンｎ－プロポキシド４０．９ｇを入れ（酸化アルミニウムと酸化ホウ素の比が１０：２となる配合）、Ｎ２ガスにて置換しながら攪拌した。アルミニウムイソプロポキシドが完全に溶解した（溶液が透明になった）後、２－プロパノール：水＝１：１の混合溶液２４．６ｇをゆっくり滴下して徐々に加水分解させると白いゲル状物質が生成した。得られた沈殿物をエタノールで洗浄し、次いで純水で洗浄し、ろ過した。その後、１２０℃で一晩（約１５時間）乾燥し、空気中３００℃で３時間焼成し、更に空気中１，０００℃で５時間焼成して白色生成物であるホウ酸アルミニウムを得た。このホウ酸アルミニウムはＸ線回折によって式１０Ａｌ２Ｏ３・２Ｂ２Ｏ３で表わされるホウ酸アルミニウムであると同定できた。また、この生成物は、式９Ａｌ２Ｏ３・２Ｂ２Ｏ３（Ａｌ１８Ｂ４Ｏ３３）とも同定できるものである。 (Production example of aluminum borate with specific composition)
In a three-necked flask immersed in a 50 ° C. hot water bath, 1.5 L of 2-propanol, 222.2 g of aluminum isopropoxide pulverized in an agate mortar and 40.9 g of boron n-propoxide are placed (aluminum oxide and boron oxide The mixture was stirred at a ratio of 10: 2) and N 2 gas. After the aluminum isopropoxide is completely dissolved (the solution becomes transparent), 24.6 g of a mixed solution of 2-propanol: water = 1: 1 is slowly dropped and gradually hydrolyzed to form a white gel-like substance. Generated. The obtained precipitate was washed with ethanol, then washed with pure water, and filtered. Then, it dried at 120 degreeC overnight (about 15 hours), baked at 300 degreeC in the air for 3 hours, and also baked at 1,000 degreeC in the air for 5 hours, and obtained the aluminum borate which is a white product. The aluminum borate were identified as aluminum borate of the formula 10Al 2 O 3 · 2B 2 O 3 by X-ray diffraction. Also, this product is one that can be identified with the formula 9Al 2 O 3 · 2B 2 O 3 (Al 18 B 4 O 33).
　この結果、酸化アルミニウムと酸化ホウ素の比が９：２となる配合としても、酸化アルミニウムと酸化ホウ素の比が１０：２となる配合としても、同一の物質が製造されることが確認された。 As a result, it was confirmed that the same substance was produced both when the ratio of aluminum oxide and boron oxide was 9: 2 and when the ratio of aluminum oxide and boron oxide was 10: 2.
　図２には、本製造例のホウ酸アルミニウムのＸ線回折の測定結果と、式１０Ａｌ２Ｏ３・２Ｂ２Ｏ３（Ａｌ２０Ｂ４Ｏ３６）で表されるホウ酸アルミニウム及び式９Ａｌ２Ｏ３・２Ｂ２Ｏ３（Ａｌ１８Ｂ４Ｏ３３）で表されるホウ酸アルミニウムの標準のカードデータを示す。 In FIG. 2, the measurement result of the X-ray diffraction of the aluminum borate of this production example, the aluminum borate represented by the formula 10Al 2 O 3 .2B 2 O 3 (Al 20 B 4 O 36 ), and the formula 9Al 2 O represents the standard of the card data of aluminum borate represented by 3 · 2B 2 O 3 (Al 18 B 4 O 33).

Claims (10)

  1. 　酸化アルミニウムと酸化ホウ素の比が１０：２～９：２の特定組成のホウ酸アルミニウムをＬａ２Ｏ３で修飾され、前記Ｌａ２Ｏ３の量がホウ酸アルミニウムの質量を基準にして０．３～２質量％である、Ｌａ２Ｏ３で修飾された特定組成のホウ酸アルミニウムを含むことを特徴とする排気ガス浄化用触媒のための担体。 The ratio of aluminum oxide, boron oxide of 10: 2-9: 2 of the specific composition of the aluminum borate modified with La 2 O 3, 0 amount of the La 2 O 3 is based on the weight of aluminum borate. A carrier for an exhaust gas purifying catalyst, comprising 3 to 2% by mass of aluminum borate having a specific composition modified with La 2 O 3 .
  2. 　前記特定組成のホウ酸アルミニウムが、式１０Ａｌ２Ｏ３・２Ｂ２Ｏ３で表わされることを特徴とする請求項１記載の排気ガス浄化用触媒のための担体。 The aluminum borate having a specific composition is a carrier for an exhaust gas purifying catalyst according to claim 1, wherein the formula 10Al 2 O 3 · 2B 2 O 3.
  3. 　前記特定組成のホウ酸アルミニウムが、式９Ａｌ２Ｏ３・２Ｂ２Ｏ３で表わされることを特徴とする請求項１記載の排気ガス浄化用触媒のための担体。 The carrier for an exhaust gas purifying catalyst according to claim 1, wherein the aluminum borate having the specific composition is represented by the formula 9Al 2 O 3 · 2B 2 O 3 .
  4. 　請求項１～３の何れか一項に記載の担体と、該担体に担持されたＰｄとを含むことを特徴とする排気ガス浄化用触媒。 An exhaust gas purifying catalyst comprising the carrier according to any one of claims 1 to 3 and Pd supported on the carrier.
  5. 　請求項１～３の何れか一項に記載の担体と、該担体に担持されたＰｄ及びＢａとを含むことを特徴とする排気ガス浄化用触媒。 An exhaust gas purifying catalyst comprising the carrier according to any one of claims 1 to 3 and Pd and Ba supported on the carrier.
  6. 　セラミックス又は金属材料からなる触媒支持体と、該触媒支持体上に担持されている請求項４又は５記載の排気ガス浄化用触媒の層とを含むことを特徴とする排気ガス浄化用触媒構成体。 An exhaust gas purifying catalyst structure comprising: a catalyst support made of a ceramic or metal material; and an exhaust gas purifying catalyst layer supported on the catalyst support. .
  7. 　セラミックス又は金属材料からなる触媒支持体と、該触媒支持体上に担持されている請求項４又は５記載の排気ガス浄化用触媒の層と、該排気ガス浄化用触媒の層の上に担持されているＲｈ触媒層とを含むことを特徴とする排気ガス浄化用触媒構成体。 A catalyst support made of a ceramic or metal material, an exhaust gas purification catalyst layer supported on the catalyst support, and an exhaust gas purification catalyst layer supported on the catalyst support layer. An exhaust gas purifying catalyst structure, comprising: an Rh catalyst layer.
  8. 　酸化アルミニウムと酸化ホウ素の比が１０：２～９：２の特定組成のホウ酸アルミニウムと、ランタン化合物の水溶液とを混合し、蒸発乾固させ、焼成してＬａ２Ｏ３で修飾された特定組成のホウ酸アルミニウムを製造し、次いで、該修飾された特定組成のホウ酸アルミニウムとＰｄ化合物の水溶液とを混合するか、又は該修飾された特定組成のホウ酸アルミニウムとＢａ化合物とＰｄ化合物の水溶液とを混合し、その後、蒸発乾固させ、焼成することを特徴とする排気ガス浄化用触媒の製造方法。 Aluminum borate having a specific composition ratio of aluminum oxide to boron oxide of 10: 2 to 9: 2 and an aqueous solution of a lanthanum compound are mixed, evaporated to dryness, baked and modified with La 2 O 3 The aluminum borate having the composition is manufactured, and then the aluminum borate having the modified specific composition and the aqueous solution of the Pd compound are mixed, or the aluminum borate, Ba compound, and the Pd compound having the modified specific composition are mixed. A method for producing an exhaust gas purifying catalyst, comprising mixing with an aqueous solution, followed by evaporating to dryness and firing.
  9. 　前記特定組成のホウ酸アルミニウムが、式１０Ａｌ２Ｏ３・２Ｂ２Ｏ３で表わされることを特徴とする請求項８記載の排気ガス浄化用触媒の製造方法。 The aluminum borate having a specific composition has the formula 10Al 2 O 3 · 2B 2 The process according to claim 8 exhaust gas purifying catalyst, wherein the represented by O 3.
  10. 　前記特定組成のホウ酸アルミニウムが、式９Ａｌ２Ｏ３・２Ｂ２Ｏ３で表わされることを特徴とする請求項８記載の排気ガス浄化用触媒の製造方法。 The aluminum borate having a specific composition has the formula 9Al 2 O 3 · 2B 2 The process according to claim 8 exhaust gas purifying catalyst, wherein the represented by O 3.
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