WO2017086308A1 - 触媒用粉末及び排気ガス浄化用触媒 - Google Patents
触媒用粉末及び排気ガス浄化用触媒 Download PDFInfo
- Publication number
- WO2017086308A1 WO2017086308A1 PCT/JP2016/083804 JP2016083804W WO2017086308A1 WO 2017086308 A1 WO2017086308 A1 WO 2017086308A1 JP 2016083804 W JP2016083804 W JP 2016083804W WO 2017086308 A1 WO2017086308 A1 WO 2017086308A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- powder
- mol
- catalyst
- ratio
- cerium
- Prior art date
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
- B01J23/38—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals
- B01J23/54—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals combined with metals, oxides or hydroxides provided for in groups B01J23/02 - B01J23/36
- B01J23/56—Platinum group metals
- B01J23/63—Platinum group metals with rare earths or actinides
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/34—Chemical or biological purification of waste gases
- B01D53/92—Chemical or biological purification of waste gases of engine exhaust gases
- B01D53/94—Chemical or biological purification of waste gases of engine exhaust gases by catalytic processes
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/34—Chemical or biological purification of waste gases
- B01D53/92—Chemical or biological purification of waste gases of engine exhaust gases
- B01D53/94—Chemical or biological purification of waste gases of engine exhaust gases by catalytic processes
- B01D53/9445—Simultaneously removing carbon monoxide, hydrocarbons or nitrogen oxides making use of three-way catalysts [TWC] or four-way-catalysts [FWC]
- B01D53/945—Simultaneously removing carbon monoxide, hydrocarbons or nitrogen oxides making use of three-way catalysts [TWC] or four-way-catalysts [FWC] characterised by a specific catalyst
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
- B01J23/10—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of rare earths
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
- B01J23/38—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals
- B01J23/40—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals of the platinum group metals
- B01J23/44—Palladium
-
- 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
- B01J33/00—Protection of catalysts, e.g. by coating
-
- 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
- B01J37/0201—Impregnation
- B01J37/0207—Pretreatment of the support
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
- F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
- F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
- F01N3/10—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
- F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
- F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
- F01N3/10—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
- F01N3/24—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by constructional aspects of converting apparatus
- F01N3/28—Construction of catalytic reactors
- F01N3/2803—Construction of catalytic reactors characterised by structure, by material or by manufacturing of catalyst support
- F01N3/2807—Metal other than sintered metal
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
- F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
- F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
- F01N3/10—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
- F01N3/24—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by constructional aspects of converting apparatus
- F01N3/28—Construction of catalytic reactors
- F01N3/2803—Construction of catalytic reactors characterised by structure, by material or by manufacturing of catalyst support
- F01N3/2832—Construction of catalytic reactors characterised by structure, by material or by manufacturing of catalyst support granular, e.g. pellets
-
- 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
- B01D2255/20—Metals or compounds thereof
- B01D2255/206—Rare earth metals
- B01D2255/2065—Cerium
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2255/00—Catalysts
- B01D2255/20—Metals or compounds thereof
- B01D2255/207—Transition metals
- B01D2255/20715—Zirconium
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2255/00—Catalysts
- B01D2255/90—Physical characteristics of catalysts
- B01D2255/908—O2-storage component incorporated in the catalyst
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
- F01N2330/00—Structure of catalyst support or particle filter
- F01N2330/06—Ceramic, e.g. monoliths
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
- F01N2330/00—Structure of catalyst support or particle filter
- F01N2330/08—Granular material
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
- F01N2370/00—Selection of materials for exhaust purification
- F01N2370/02—Selection of materials for exhaust purification used in catalytic reactors
- F01N2370/04—Zeolitic material
Definitions
- the present invention relates to a catalyst powder containing ceria and zirconia, and an exhaust gas purification catalyst using the catalyst powder.
- the exhaust gas discharged from internal combustion engines such as automobiles and motorcycles contains harmful components such as HC, CO, and NOx (nitrogen oxide).
- a three-way catalyst has been used for the purpose of purifying and detoxifying these harmful components.
- a material having an OSC Oxygen Storage Capacity
- OSC Oxygen Storage Capacity
- CeO 2 and ZrO 2 As a material having this OSC.
- the solid solution of CeO 2 and ZrO 2 has OSC that absorbs and releases oxygen in the crystal structure by the surrounding atmosphere.
- Patent Document 1 describes a carrier for an exhaust gas purification catalyst for an internal combustion engine in which CeO 2 is supported on the surface of a core material made of a solid solution of CeO 2 —ZrO 2 .
- Patent Document 2 discloses an automotive exhaust gas purifying co-catalyst material having a zirconia core and ceria zirconia and ceria existing on the surface of the core, and the ceria utilization rate at 800 ° C. is 91 to 97%. What you have is described.
- Patent Document 3 discloses an exhaust gas purifying catalyst in which rhodium is supported on metal oxide particles, wherein the metal oxide particles include a central portion containing a relatively large amount of ceria and a skin portion containing a relatively large amount of zirconia. An exhaust gas purifying catalyst is described.
- the co-catalyst material in Patent Document 2 is said to have a high effective Ce rate at a high temperature, but the core material is made of zirconia, and the core part does not have OSC, so the total OSC is low. Further, Patent Document 2 does not examine the effective Ce rate at low and intermediate temperatures. Furthermore, as described in Patent Document 3, the catalyst having a surface made of zirconia does not have OSC in the outer skin portion, and thus is not sufficient in terms of an effective Ce rate at a low intermediate temperature.
- An object of the present invention is to provide a catalyst powder that can eliminate the various drawbacks of the above-described conventional technology and an exhaust gas purification catalyst using the catalyst powder.
- the present inventors surprisingly include CeO 2 and ZrO 2 in both the core part and the surface layer part of the catalyst powder, and reduce the amount of CeO 2 in the surface part as compared with the core part.
- the present inventors have found that the effective Ce ratio at low and medium temperatures after high temperature durability can be greatly improved.
- the present invention is a powder for catalyst having a core part containing ceria and zirconia, and a surface layer part located on the core part and containing ceria and zirconia, Ratio (M 2 / M 1 ) of the molar fraction M 2 (mol%) of cerium in the surface layer portion measured by X-ray photoelectron spectroscopy to the molar fraction M 1 (mol%) of cerium in the whole powder ) Is 0.30 or more and 0.95 or less.
- the present invention also provides an exhaust gas purifying catalyst comprising a catalyst powder and a noble metal supported on the catalyst powder.
- a catalyst powder from which an exhaust gas purifying catalyst having a high effective Ce rate at low and intermediate temperatures after high temperature durability can be obtained.
- the catalyst powder and the exhaust gas purifying catalyst of the present invention make use of this characteristic and are usefully used for exhaust gas purifying catalyst applications in internal combustion engines such as automobiles and motorcycles.
- the catalyst powder of the present invention is a catalyst powder having a core part containing ceria and zirconia and a surface layer part located on the core part and containing ceria and zirconia.
- the catalyst powder of the present invention is characterized by containing ceria and zirconia in both the core part and the surface layer part. It is preferable that both the core part and the surface layer part contain a solid solution with zirconia as ceria. However, as long as the effects of the present invention are not impaired, the ceria may contain a ceria single phase.
- the surface layer part is usually present on the surface of the core part, and preferably covers the entire surface of the core part. However, as long as the effect of the present invention is not impaired, there may be a part where the surface of the core part is exposed.
- the powder has a structure having a core portion and a surface layer portion and has a core portion containing ceria and zirconia.
- XPS X-ray photoelectron spectroscopy
- the catalyst powder of the present invention has a form in which the composition changes stepwise (discontinuously) from the center of the powder to the surface (for example, a core portion and a surface layer portion having predetermined compositions different from each other with an interface between them).
- the present invention is not limited to this.
- the composition may be continuously (gradually) changed from the center portion to the surface layer portion.
- the present inventors include ceria and zirconia in both the core portion and the surface layer portion, Further, it has been found that if the ratio of ceria in the surface layer portion is low at a constant rate as compared with the core portion, the efficiency of oxygen absorption / release is greatly improved at low and intermediate temperatures after high temperature durability.
- the catalyst powder containing ceria and zirconia of the present invention has a cerium mole fraction M 2 on the surface of the catalyst powder measured by X-ray photoelectron spectroscopy with respect to the cerium mole fraction M 1 (mol%) of the whole powder.
- the ratio of (mol%) is used as an index.
- the ratio (M 2 / M 1 ) of the molar fraction M 2 (mol%) of cerium measured by X-ray photoelectron spectroscopy to the molar fraction M 1 (mol%) of cerium in the whole powder It is 0.30 or more and 0.95 or less.
- M 2 / M 1 is preferably 0.50 or more and 0.90 or less, and more preferably 0.75 or more and 0.90 or less.
- Measurement of the molar fraction M 2 by X-ray photoelectron spectroscopy may be carried out by methods described in the examples below.
- the mole fraction of the specific metal by X-ray photoelectron spectroscopy is the ratio of the number of moles of the specific metal atom to the “number of moles of all metal atoms present on the powder surface measured by X-ray photoelectron spectroscopy”. Represents.
- the surface layer portion refers to the surface portion of the powder measured by X-ray photoelectron spectroscopy.
- the core portion refers to a portion located on the center side of the particle from the surface layer portion.
- the cerium molar fraction M 1 of the whole powder can be calculated by the composition of the raw material at the time of production, or can be measured by measuring the amount of cerium in a solution obtained by dissolving the powder by alkali melting or the like with ICP-AES. .
- M 2 is preferably 1.0 mol% or more and 40.0 mol% or less, more preferably 3.0 mol% or more and 40.0 mol% or less, and 5.0 mol% or more and 30.0 mol% or less. More preferably, it is as follows.
- the molar fraction M 1 of cerium in the whole powder is preferably 3.0 mol% or more and 49.0 mol% or less from the viewpoint of further enhancing the effect of the present invention, and is 10.0 mol% or more and 45.0 mol% or less. It is more preferable.
- the catalyst powder of the present invention it is preferable to increase the proportion of zirconia in the surface layer portion higher than that of ceria in order to more surely exhibit the effect of the present invention that increases the effective Ce rate at low and intermediate temperatures after high heat durability.
- the ratio M 4/2 is preferably larger than 1 from the viewpoint of increasing the effective Ce rate at a low intermediate temperature after high heat durability.
- the ratio M 4/2 is preferably 30 or less from the viewpoint of making the OSC of the catalyst powder sufficient. From these viewpoints, M 4/2 is more preferably 1.1 or more and 20.0 or less, and further preferably 1.1 or more and 15.0 or less.
- this ratio (M 4/2 / M 3/1 ) is 1.1 or more, it means that the molar ratio of zirconia / ceria on the powder surface exceeds the molar ratio of zirconia / ceria in the whole powder by a certain amount or more. To do.
- Such a catalyst powder is preferable from the viewpoint of further reliably achieving the effect of the present invention to increase the effective Ce rate after heat endurance.
- the ratio (M 4/2 / M 3/1 ) being 5.0 or less enhances the effective Ce ratio after heat endurance and the viewpoint that a powder for a catalyst having both heat resistance and OSC can be obtained.
- the ratio (M 4/2 / M 3/1 ) is more preferably 1.1 or more and 3.5 or less, further preferably 1.1 or more and 2.0 or less. More preferably, it is 2 or more and 2.0 or less.
- the molar fraction M 4 of zirconium in the surface layer portion measured by X-ray photoelectron spectroscopy is preferably 50.0 mol% or more from the viewpoint of improving heat resistance by containing a certain amount of zirconia on the powder surface, 90.
- the amount is preferably 0 mol% or less from the viewpoint of sufficient OSC due to ceria.
- M 4 is more preferably 50.0 mol% or more and 80.0 mol% or less, and further preferably 55.0 mol% or more and 80.0 mol% or less.
- the ratio (M 4 / M 3 ) of the molar fraction M 4 of zirconium measured by X-ray photoelectron spectroscopy to the molar fraction M 3 (mol%) of zirconium in the whole powder is 1.0 or more and 1 Is preferably 0.9 or less, more preferably 1.0 or more and 1.7 or less.
- the molar fraction M 3 of zirconium in the whole powder is preferably 50.0 mol% or more and 95.0 mol% or less from the viewpoint of further enhancing the effect of the present invention, and is 50.0 mol% or more and 90.0 mol% or less. More preferably, it is 50.0 mol% or more and 80.0 mol% or less. Mole fraction M 3 of the whole powder zirconium can be obtained in the same manner as the mole fraction M 1 of the entire powder of cerium.
- the catalyst powder preferably contains a rare earth oxide other than ceria and / or an alkaline earth metal oxide.
- a rare earth oxide other than ceria and / or alkaline earth metal oxide By containing rare earth oxides other than ceria and / or alkaline earth metal oxides, the effective Ce rate at low and medium temperatures after high temperature durability can be improved, and noble metal dispersion can be achieved by noble metal-support interaction. The degree can be increased.
- rare earth elements other than cerium include scandium (Sc), yttrium (Y), lanthanum (La), praseodymium (Pr), neodymium (Nd), samarium (Sm), europium (Eu), gadolinium (Gd), terbium ( Mention may be made of Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb) and lutetium (Lu).
- rare earth oxides and / or alkaline earth metal oxides may or may not form a solid solution with ceria and / or zirconia.
- yttria Y 2 O 3
- lanthanum oxide La 2 O 3
- Pr 6 O 11 praseodymium oxide
- Nd 2 O 3 neodymium oxide
- strontium oxide SrO
- barium oxide BaO It is preferable to contain 1 type, or 2 or more types selected from.
- the catalyst powder may contain only one kind of rare earth element oxide and / or alkaline earth metal oxide other than ceria, but the fact that it contains two or more kinds from the viewpoint of enhancing the effect of the present invention. Preferably, 3 or more types are contained. Thereby, the effective Ce rate at low and medium temperatures can be further improved by having the effects such as heat resistance and structural stability exhibited by each additive element.
- the core portion and the surface layer portion may have the same rare earth element and / or alkaline earth metal element other than Ce, or have different types of rare earth elements and / or alkaline earth metal elements other than Ce. May be.
- the design is a combination of a rare earth element oxide other than ceria that can improve the precious metal dispersion and an alkaline earth metal oxide that suppresses sintering of the precious metal at high temperatures, This is preferable from the viewpoint of further improvement.
- the amount of rare earth element oxide and / or alkaline earth metal oxide other than ceria is preferably 1 part by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the whole powder.
- the content of 1 part by mass or more is preferable from the viewpoint of further enhancing the effect of the rare earth element oxide described above.
- the content of the rare earth element oxide other than ceria is more preferably 2 parts by mass or more and 20 parts by mass or less, and more preferably 4 parts by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the whole powder. More preferably it is.
- the amount of the rare earth element oxide and / or alkaline earth metal oxide other than ceria is preferably 5 parts by mass or more with respect to 100 parts by mass of the whole powder from the viewpoint of improving the precious metal dispersion.
- the amount of the rare earth element oxides other than ceria powder and / or alkaline earth metal oxides, as well as the mole fraction M 1 of the entire powder cerium powder in the solution obtained by dissolving an alkali melt such as It can be measured by measuring the amount of rare earth elements other than cerium and / or alkaline earth metal elements by ICP-AES.
- the amount of “rare earth element oxide and / or alkaline earth metal oxide other than ceria” is the amount when the powder contains only one of rare earth element oxide and alkaline earth metal oxide other than ceria. Yes, if both are included, it is the total amount.
- molar fraction M 5 of the superficial layer of the rare earth elements and / or alkaline earth metal element other than cerium is measured by X-ray photoelectron spectroscopy is not less than 1.0 mol% Is more preferable, 5.0 mol% or more is more preferable, and 10.0 mol% or more is particularly preferable.
- M 5 is 50.0 mol% or less, particularly 40.0 mol% or less, especially 20.0 mol% or less, ensuring a certain amount of ceria and zirconia in the powder, and more reliably the effect of the present invention. From the viewpoint of obtaining.
- the ratio (M 5 / M 6 ) of the molar fraction M 5 of the element is preferably 0.5 or more and 10.0 or less, and more preferably 1.0 or more and 5.0 or less.
- “Mole fraction of rare earth elements other than cerium and / or alkaline earth metal elements” is the mole fraction when only one of the rare earth elements other than cerium and alkaline earth metal elements is included, When included, it is the sum of the molar fractions of both.
- a rare earth other than cerium in the surface layer portion measured by X-ray photoelectron spectroscopy with respect to the molar fraction M 2 of cerium in the surface layer portion measured by X-ray photoelectron spectroscopy is preferably 0.1 or more and 8.0 or less, and is 0.3 or more and 3.0 or less. It is more preferable.
- the catalyst powder of the present invention usually preferably has core particles containing ceria and zirconia, and a supported metal oxide supported on the surface of the core particles.
- a catalyst powder of this invention may be a surface layer portion, it is easily formed so as to satisfy M 2 / M 1 described above.
- the supported metal oxide may or may not contain ceria and / or zirconia.
- the ceria and zirconia of the core particle are contained, so that ceria and zirconia are included in the surface layer portion. Zirconia can be included, and M 2 / M 1 described above can be satisfied.
- the supported metal oxide preferably contains ceria and zirconia.
- a supported metal oxide containing ceria and zirconia is supported on the core particles containing ceria and zirconia in the catalyst powder can be observed using STEM-EDX.
- the zirconia and ceria peaks fluctuate at a certain position between the particle surface side and the center side, such that the ceria peak at the end is small and the internal ceria peak is strong.
- the core part of this invention comprises at least one part of a core particle.
- the core part may be composed only of core particles or may contain a part of the supported metal oxide.
- the surface layer portion of the present invention constitutes at least a part of the supported metal oxide.
- the supported metal oxide may be composed only of the supported metal oxide or may include some core particles. Examples of supported metal oxides other than ceria and zirconia include rare earth element oxides and / or alkaline earth metal oxides other than Ce. Needless to say, the rare earth elements and alkaline earth metals other than Ce mentioned here include those mentioned above.
- the catalyst powder of the present invention preferably has an average particle size (D 50 ) of 100 ⁇ m or less from the viewpoint of catalyst preparation.
- the average particle diameter (D 50 ) of the catalyst powder is preferably 1 ⁇ m or more from the viewpoint of catalyst preparation. From these viewpoints, the average particle diameter (D 50 ) of the catalyst powder is preferably 1 ⁇ m or more and 100 ⁇ m or less, and more preferably 2 ⁇ m or more and 50 ⁇ m or less.
- the average particle size (D 50 ) of the catalyst powder is a 50% cumulative volume particle size measured by a laser diffraction / scattering particle size distribution measuring method. For example, an automatic sample feeder for a laser diffraction particle size distribution measuring device (“Nikkiso Co., Ltd.
- Microtorac SDC a sample (powder) was put into a water-soluble solvent, and 40 W ultrasonic waves were irradiated for 360 seconds at a flow rate of 40%, and then Microtrack MT3300II manufactured by Nikkiso Co., Ltd. or Microtrack Corporation was used. Measured. Measurement conditions are determined as an average value of particle refractive index 1.5, particle shape true sphere, solvent refractive index 1.3, set zero 30 seconds, measurement time 30 seconds, and twice measurement.
- the catalyst powder of the present invention is preferably used as an exhaust gas purifying catalyst by supporting a noble metal thereon.
- the noble metal include palladium (Pd), platinum (Pt), rhodium (Rh) and the like.
- the amount of the noble metal supported is preferably 0.1 parts by mass or more and 20 parts by mass or less, preferably 1 part by mass or more and 10 parts by mass or less per 100 parts by mass of the total amount of the catalyst powder and the noble metal. More preferred.
- Amount of the noble metal, as well as the mole fraction M 1 of the entire powder of cerium, the amount of noble metal in the resulting solution by dissolving a catalyst with an alkali melt such as can be measured by measuring at ICP-AES.
- the catalyst powder of the present invention is suitably produced, for example, by the following production method.
- This production method refers to an aqueous solution containing a water-soluble cerium salt and a water-soluble zirconium salt adjusted to pH 9.0 or higher and 14.0 or lower to obtain a first precipitate, and the first precipitate is calcined.
- a first step of forming a core material The core material generated in the first step, the water-soluble salt of the supported metal, and the dispersion are adjusted to pH 9.0 or higher and 14.0 or lower to obtain a second precipitate, and the second precipitate
- Preferred examples of the water-soluble salt of the supported metal include water-soluble cerium salts and water-soluble zirconium salts.
- Examples of the water-soluble cerium salt include compounds that can be changed to CeO 2 by firing, such as cerium nitrate.
- Examples of the water-soluble zirconium salt include compounds that can be changed to ZrO 2 by firing, such as zirconium oxynitrate.
- an alkaline agent such as ammonium carbonate or sodium hydroxide. Calcination of the first precipitate can be performed in an air atmosphere, and can be performed, for example, at 600 ° C. to 1000 ° C. for 1 hour to 24 hours.
- the second precipitate can be fired in an air atmosphere, for example, 600 ° C. or more and 1000 ° C. or less and 1 hour or more and 24 hours or less.
- the aqueous solution of the water-soluble Ce salt and Zr salt in the first step and / or the coating in the second step contains a water-soluble salt of a rare earth element other than Ce and / or an alkaline earth metal.
- cerium and zirconium are not used as the supported metal, rare earth elements other than Ce and / or alkaline earth metals may be used exclusively as the water-soluble salt in the dispersion.
- the amount of the cerium salt in the first step is adjusted so as to be 5% by mass or more and 58% by mass or less in terms of ceria, based on the mass of the oxide when all the metal salts contained in the aqueous solution are oxides. It is preferably 20% by mass or more and 58% by mass or less.
- the amount of the zirconium salt in the first step is adjusted to be 42% by mass or more and 95% by mass or less in terms of zirconia, based on the mass of the oxide when all the metal salts contained in the aqueous solution are oxides. It is preferable to be 42% by mass or more and 80% by mass or less.
- the rare earth element salt other than cerium is prepared so as to be 1% by mass or more and 20% by mass or less in terms of rare earth element oxide based on the mass of the oxide when all the metal salts contained in the aqueous solution are converted into oxides. It is preferable to do.
- the amount of the cerium salt used in the second step is 5% by mass in terms of ceria, based on the mass of the metal oxide other than the core material produced when all the water-soluble metal salts in the dispersion before pH adjustment are converted into oxides. It is preferable to prepare such that the amount is 58% by mass or less and less than the ratio of the cerium salt in the first step.
- the amount of the zirconium salt in the second step is 42% by mass in terms of zirconia, based on the mass of the metal oxide other than the core material generated when all the water-soluble metal salt contained in the dispersion before pH adjustment is converted into an oxide. It is preferable to prepare so that it may become 95 mass% or less.
- the rare earth element salt other than cerium is 1% by mass or more and 35% by mass or less in terms of rare earth element oxide based on the mass of the metal oxide other than the oxide core material in the water-soluble metal salt in the dispersion before pH adjustment. It is preferable to prepare such that
- the amount ratio between the water-soluble metal salt and the core material in the dispersion in the second step is equivalent to the mass of all water-soluble metal oxides in the dispersion (corresponding to the mass of the unsupported metal oxide, and the surface layer portion).
- the ratio of the mass of the core material to the mass of the core material is preferably 1: 0.2 or more and 99 or less, more preferably 1: 1 or more and 20 or less.
- the catalyst powder In order to support the noble metal on the catalyst powder, it is preferable to immerse the catalyst powder in a noble metal-containing solution, and then dry and calcine it.
- a noble metal-containing solution As the noble metal salt used for preparing the noble metal solution, for example, nitrate, ammine complex salt, chloride or the like is used.
- the solvent water or the like can be used. Firing is preferably performed in an air atmosphere at 400 ° C. to 800 ° C. for 1 hour to 24 hours. The firing temperature may be different within the above-described range between the first step and the second step.
- the calcination temperature in the first step can be made higher than the calcination temperature in the second step, and with such a design, the precious metal dispersibility in the initial stage of purification of the exhaust gas purification catalyst is improved. be able to.
- the exhaust gas purifying catalyst in which the noble metal is supported on the catalyst powder as described above exhibits a stable OSC even when exposed to a high temperature of about 800 ° C. or higher and 1100 ° C. or lower.
- a high effective Ce rate is shown at 400 ° C., which is the temperature of the engine when the engine is started, and at 600 ° C., which is the temperature when the engine is subsequently accelerated to start high-speed steady operation.
- Such an exhaust gas purification catalyst can exhibit stable and high exhaust gas purification performance as an exhaust gas purification catalyst of an internal combustion engine that uses fossil fuel as a power source such as a gasoline engine or a diesel engine.
- Example 1 (second step) Compared to the aqueous solution containing cerium nitrate, zirconium oxynitrate, lanthanum nitrate, and neodymium nitrate as raw materials in the ratios shown in Table 1 (supported metal oxide) when they are used as oxides.
- the powder obtained in Example 1 was added to prepare a dispersion.
- sodium hydroxide was added as a precipitating agent in such an amount that the pH became 12.0.
- the obtained precipitate was filtered, washed, sufficiently dried, and then calcined at 800 ° C. for 3 hours in an air atmosphere to obtain a catalyst powder of Example 1.
- the quantity ratio between the powder of Comparative Example 1 and the nitrate contained in the aqueous solution in the second step is such that the mass ratio of the powder and the oxide derived from the nitrate is “core particle: supported metal oxide” in Table 1. It adjusted so that it might become the ratio as described in the column of.
- Example 2-9 Comparative Example 2
- the amounts of cerium nitrate, zirconium oxynitrate, lanthanum nitrate, and neodymium nitrate in the raw materials were set to the ratios shown in Table 1 (supported metal oxide term), and the powder of Comparative Example 1 and the second sample
- the amount ratio of nitrate to be contained in the aqueous solution of the process is such that the mass ratio of the powder and the oxide derived from the nitrate is the ratio described in the column “core particle: supported metal oxide” in Table 1. Adjusted. Except for these points, it was the same as Example 1.
- Example 7 in the dispersion in the second step, praseodymium nitrate was added in addition to the nitrates, and in Example 8, in the dispersion in the second step, yttrium nitrate was added to the nitrates in addition to the nitrates.
- the ratios shown in Table 1 were used.
- the dispersion in the second step was prepared by adding the powder obtained in Comparative Example 1 to an aqueous solution containing only zirconium oxynitrate as a metal water-soluble salt.
- the amount ratio between the powder of Comparative Example 1 and the nitrate contained in the aqueous solution in the second step is such that the mass ratio of the powder and the oxide derived from the nitrate is “core particle: supported metal oxide” in Table 1. It adjusted so that it might become the ratio of description in a column. Thereafter, sodium hydroxide as a precipitating agent was added to the dispersion in such an amount that the pH became 12.0. Except for these points, it was the same as Example 1.
- the dispersion in the second step was prepared by adding the powder obtained in Comparative Example 1 to an aqueous solution containing only praseodymium nitrate as a metal water-soluble salt.
- the amount ratio between the powder of Comparative Example 1 and the nitrate contained in the aqueous solution in the second step is such that the mass ratio of the powder and the oxide derived from the nitrate is “core particle: supported metal oxide” in Table 1. It adjusted so that it might become the ratio of description in a column. Thereafter, sodium hydroxide as a precipitating agent was added to the dispersion in such an amount that the pH became 12.0. Except for these points, it was the same as Example 1.
- Example 10 (second step)
- the catalyst powder of Comparative Example 5 was added to an aqueous solution containing, as raw materials, cerium nitrate and zirconium oxynitrate in the ratio shown in Table 1 (term of supported metal oxide) when they were converted into oxides.
- a dispersion was prepared by addition.
- the amount ratio between the powder of Comparative Example 5 and the nitrate contained in the aqueous solution of the second step is such that the mass ratio of the powder and the oxide derived from the nitrate is “core particle: supported metal oxide” in Table 1. It adjusted so that it might become the ratio of description in a column.
- sodium hydroxide as a precipitating agent was added to the dispersion in such an amount that the pH became 12.0.
- the obtained precipitate was filtered, washed, sufficiently dried, and then calcined at 800 ° C. for 3 hours to obtain a catalyst powder of Example 10.
- the dispersion in the second step was prepared by adding the powder obtained in Comparative Example 1 to an aqueous solution containing only cerium nitrate as the metal water-soluble salt.
- the amount ratio between the powder of Comparative Example 1 and the nitrate contained in the aqueous solution in the second step is such that the mass ratio of the powder and the oxide derived from the nitrate is “core particle: supported metal oxide” in Table 1. It adjusted so that it might become the ratio of description in a column. Thereafter, sodium hydroxide as a precipitating agent was added to the dispersion in such an amount that the pH became 12.0. Except for these points, it was the same as Example 1.
- Example 11-14 In Example 1, the amounts of cerium nitrate, zirconium oxynitrate, lanthanum nitrate, and neodymium nitrate, and praseodymium nitrate, yttrium nitrate, and / or strontium nitrate in the raw materials are as shown in Table 1 (section of supported metal oxide).
- the ratio of the powder of Comparative Example 1 and the nitrate contained in the aqueous solution of the second step is the mass ratio of the powder and the oxide derived from the nitrate “core particles: supported” in Table 1. The ratio was adjusted to the ratio described in the column “Metal oxide”. Except for these points, it was the same as Example 1.
- Example 15 In Example 1, the amounts of yttrium nitrate and strontium nitrate in the raw materials were set to the ratios shown in Table 1 (supported metal oxide term), and nitrates contained in the powder of Comparative Example 1 and the aqueous solution in the second step was adjusted so that the mass ratio of the powder and the oxide derived from the nitrate would be the ratio described in the column “core particle: supported metal oxide” in Table 1. Except for these points, it was the same as Example 1.
- M 5 of the rare earth element and / or alkaline earth metal element other than ceria in the surface layer part and the molar fraction M 6 of the rare earth element and / or alkaline earth metal element other than ceria in the whole powder are obtained, M 5 / M was calculated 2 and M 5 / M 6.
- XPS Quantum 2000 manufactured by ULVAC-PHI was used as an X-ray photoelectron spectroscopic analyzer.
- AlK ⁇ 1 ray 1486.8 eV
- X-ray irradiation area 200 ⁇ m ⁇
- pass energy 23.5 eV
- measurement depth several nm
- measurement interval 0 0.1 eV
- tube voltage 15 kV
- tube current 2.67 mA
- the number of scans was 10 conditions for each element.
- “Multipack Ver6.1A” manufactured by ULVAC-PHI was used.
- Each of the catalyst powders of Examples 1 to 15 and Comparative Examples 1 to 6 was added to a palladium nitrate (II) aqueous solution, and the palladium loading concentration converted to the mass of palladium metal was based on the total amount of the catalyst powder and palladium metal. Impregnation was performed at a ratio of 1.0% by mass. Then, after evaporating to dryness, firing was performed at 600 ° C. for 3 hours in an air atmosphere to obtain a catalyst powder which is a Pd-supported CeO 2 —ZrO 2 -based composite oxide.
- II palladium nitrate
- the obtained catalyst powder was subjected to durable baking at 950 ° C. in the air for 24 hours, and then the following evaluation was performed.
- Comparative Example 1 having a uniform composition and M 2/1 close to 1
- Comparative Examples 2 and 6 having a large amount of ceria in the surface layer portion and M 2/1 larger than that of the present invention, and the oxide on the surface side supported by the core material does not contain ceria.
- the catalyst of each Example has a high effective Ce rate of 400 to 600 ° C. Even when no rare earth element other than Ce is contained, the effective Ce rate in Example 10 is higher than that in Comparative Example 5 having a uniform composition. From these results, it can be seen that in the catalyst of each Example, oxygen absorption / release occurs more efficiently than the catalysts of Comparative Examples 1 to 6 at low and intermediate temperatures after high temperature durability.
- the catalysts of Examples 1 to 9 and 11 to 15 containing rare earth elements other than Ce were effective against the catalyst of Example 10 not containing the rare earth elements.
- the Ce rate was improved. From the above, it can be seen that the catalyst powder of the present invention and the catalyst loaded with a noble metal exhibit an excellent effect for exhaust gas purification for internal combustion engines, particularly for exhaust gas purification generated at low and intermediate temperatures.
- Comparative Example 1 having a uniform composition
- Comparative Example 2 having more ceria in the surface layer than the present invention
- Comparative Examples 3 and 4 in which the oxide on the surface side supported on the core material does not contain ceria
- the catalysts of Examples 1 to 9 and 11 to 15 have noble metal dispersion equal to or higher than that.
- the catalyst of Example 10 with respect to Comparative Example 5 has a noble metal dispersion equal to or higher than that.
- the samples of Examples 5 to 8 and 11 to 15 containing a large amount of rare earth elements other than Ce have high noble metal dispersion. It was suggested that addition of rare earth other than Ce is effective in suppressing sintering of the noble metal due to the heat resistance of the support and the noble metal-support interaction.
- the catalyst powder and catalyst of the present invention are excellent for exhaust gas purification for internal combustion engines, particularly for exhaust gas purification generated at low and medium temperatures, in that the catalytic activity of noble metals is maintained high. I understand.
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Materials Engineering (AREA)
- Organic Chemistry (AREA)
- Combustion & Propulsion (AREA)
- Health & Medical Sciences (AREA)
- Mechanical Engineering (AREA)
- Toxicology (AREA)
- General Engineering & Computer Science (AREA)
- Biomedical Technology (AREA)
- Environmental & Geological Engineering (AREA)
- Analytical Chemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Catalysts (AREA)
- Exhaust Gas Treatment By Means Of Catalyst (AREA)
- Exhaust Gas After Treatment (AREA)
Abstract
Description
従来から、これらの有害成分を浄化して無害化する目的で三元触媒が用いられている。それらの三元触媒の中には、排気ガスの酸素濃度の変動を緩和させてHC、CO、NOxを効率よく浄化させるためにOSC(酸素貯蔵能:Oxygen Storage Capacity)を有する材料を触媒構成材として使用しているものもあり、このOSCを有する材料としてCeO2及びZrO2の固溶体を使用しているものがある。CeO2及びZrO2の固溶体は、周囲の雰囲気によって結晶構造中の酸素を吸放出するOSCを有している。
一方、特許文献2での助触媒材は、高温での有効Ce率が高いとされているが、コア材をジルコニアとしており、コア部がOSCを有していないため、総OSCが低い。また特許文献2は低中温での有効Ce率について何ら検討していない。
更に、特許文献3に記載のように表面がジルコニアからなる触媒は、外皮部にOSCを有していないため、低中温の有効Ce率の点で十分なものでなかった。
前記粉末全体のセリウムのモル分率M1(mol%)に対し、X線光電子分光法で測定される前記表層部のセリウムのモル分率M2(mol%)の比(M2/M1)が0.30以上0.95以下である、触媒用粉末を提供するものである。
本発明の触媒用粉末は、セリア及びジルコニアを含むコア部と、該コア部上に位置し、セリア及びジルコニアを含む表層部とを有する触媒用粉末である。このように本発明の触媒用粉末はコア部及び表層部の両方に、セリア及びジルコニアを含むことを特徴の一つとしている。コア部及び表層部はいずれも、セリアとして、ジルコニアとの固溶体を含んでいることが好ましい。しかしながら本発明の効果を損なわない範囲で、セリアとして、セリア単独相を含んでいてもよい。表層部は、通常コア部の表面に存在し、コア部の表面の全体を被覆していることが好ましい。しかし、本発明の効果を損なわない範囲で、一部にコア部の表面が露出している部位があってもよい。
本発明のセリア及びジルコニアを含有する触媒用粉末は、粉末全体のセリウムのモル分率M1(mol%)に対するX線光電子分光法で測定される触媒用粉末表面のセリウムのモル分率M2(mol%)の比を指標とする。本発明では粉末全体のセリウムのモル分率M1(mol%)に対し、X線光電子分光法で測定されるセリウムのモル分率M2(mol%)の比(M2/M1)が0.30以上0.95以下である。
本製造方法とは、水溶性のセリウム塩及び水溶性のジルコニウム塩を含有する水溶液をpH9.0以上14.0以下に調整して第1の沈殿物を得、該第1の沈殿物を焼成してコア材を形成する第1工程と、
前記第1工程で生成したコア材と、前記の被担持金属の水溶性塩と、分散液をpH9.0以上14.0以下に調整して第2の沈殿物を得、該第2の沈殿物を焼成する第2工程と、を有する。前記の被担持金属の水溶性塩としては、水溶性セリウム塩及び水溶性ジルコニウム塩が好ましく挙げられる。
原料として、硝酸セリウム、オキシ硝酸ジルコニウム、硝酸ランタン、及び硝酸ネオジムを、それらを酸化物としたときに下記表1に示す組成となる比率で含有する水溶液に、沈殿剤として水酸化ナトリウムをpHが12.0となる量で添加した。得られた沈殿物を濾過、洗浄し、十分に乾燥させ、その後、大気雰囲気下800℃で3時間焼成することにより比較例1の触媒用粉末を得た。
原料として、硝酸セリウム、オキシ硝酸ジルコニウム、硝酸ランタン、及び硝酸ネオジムを、それらを酸化物としたときに表1(被担持金属酸化物の項)に示す組成となる比率で含有する水溶液に、比較例1で得られた粉末を添加し、分散液を調製した。この分散液に、沈殿剤として水酸化ナトリウムをpHが12.0となる量で添加した。得られた沈殿物を濾過、洗浄し、十分に乾燥させ、その後大気雰囲気下、800℃で3時間焼成することにより実施例1の触媒用粉末を得た。なお比較例1の粉末と第2工程の水溶液に含有させる硝酸塩との量比は、該粉末と該硝酸塩に由来する酸化物との質量比が表1の「コア粒子:被担持金属酸化物」の欄に記載の比率になるように調整した。
実施例1において、原料における硝酸セリウム、オキシ硝酸ジルコニウム、硝酸ランタン、及び硝酸ネオジムの量を表1(被担持金属酸化物の項)に示す組成となる比率とし、比較例1の粉末と第2工程の水溶液に含有させる硝酸塩との量比は、該粉末と該硝酸塩に由来する酸化物との質量比が表1の「コア粒子:被担持金属酸化物」の欄に記載の比率になるように調整した。それらの点以外は実施例1と同様とした。ただし、実施例7では第2工程における分散液において、前記各硝酸塩に加えて硝酸プラセオジムを、実施例8では第2工程における分散液において、前記各硝酸塩に加えて硝酸イットリウムを、それぞれ酸化物としたときに表1に示す組成となる比率で用いた。
第2工程における分散液を、金属水溶性塩としてオキシ硝酸ジルコニウムのみを含有する水溶液に、比較例1で得られた粉末を添加することにより調製した。比較例1の粉末と第2工程の水溶液に含有させる硝酸塩との量比は、該粉末と該硝酸塩に由来する酸化物との質量比が表1の「コア粒子:被担持金属酸化物」の欄に記載の比率になるように調整した。その後、この分散液に、沈殿剤として水酸化ナトリウムをpHが12.0となる量で添加した。これらの点以外は、実施例1と同様とした。
第2工程における分散液を、金属水溶性塩として硝酸プラセオジムのみを含有する水溶液に、比較例1で得られた粉末を添加して調製した。比較例1の粉末と第2工程の水溶液に含有させる硝酸塩との量比は、該粉末と該硝酸塩に由来する酸化物との質量比が表1の「コア粒子:被担持金属酸化物」の欄に記載の比率になるように調整した。その後、この分散液に、沈殿剤として水酸化ナトリウムをpHが12.0となる量で添加した。これらの点以外は、実施例1と同様とした。
原料として、硝酸セリウム、オキシ硝酸ジルコニウムを、それらを酸化物としたときに表1に示す組成となる比率で含有する水溶液を調製した。この水溶液に、沈殿剤として水酸化ナトリウムをpHが12.0となる量で添加した。得られた沈殿物を濾過、洗浄し、十分に乾燥させ、その後、800℃で3時間焼成することにより触媒用粉末を得た。
原料として、硝酸セリウム、オキシ硝酸ジルコニウムを、それらを酸化物としたときに表1(被担持金属酸化物の項)に示す組成となる比率で含有する水溶液に、比較例5の触媒用粉末を添加して分散液を調製した。比較例5の粉末と第2工程の水溶液に含有させる硝酸塩との量比は、該粉末と該硝酸塩に由来する酸化物との質量比が表1の「コア粒子:被担持金属酸化物」の欄に記載の比率になるように調整した。その後、この分散液に、沈殿剤として水酸化ナトリウムをpHが12.0となる量で添加した。得られた沈殿物を濾過、洗浄し、十分に乾燥させ、その後、800℃で3時間焼成することにより実施例10の触媒用粉末を得た。
第2工程における分散液を、金属水溶性塩として硝酸セリウムのみを含有する水溶液に、比較例1で得られた粉末を添加することにより調製した。比較例1の粉末と第2工程の水溶液に含有させる硝酸塩との量比は、該粉末と該硝酸塩に由来する酸化物との質量比が表1の「コア粒子:被担持金属酸化物」の欄に記載の比率になるように調整した。その後、この分散液に、沈殿剤として水酸化ナトリウムをpHが12.0となる量で添加した。これらの点以外は、実施例1と同様とした。
実施例1において、原料における硝酸セリウム、オキシ硝酸ジルコニウム、硝酸ランタン、及び硝酸ネオジム、並びに硝酸プラセオジム、硝酸イットリウム及び/又は硝酸ストロンチウムの量を表1(被担持金属酸化物の項)に示す組成となる比率とし、また比較例1の粉末と第2工程の水溶液に含有させる硝酸塩との量比を、該粉末と該硝酸塩に由来する酸化物との質量比が表1の「コア粒子:被担持金属酸化物」の欄に記載の比率になるように調整した。それらの点以外は実施例1と同様とした。
実施例1において、原料における硝酸イットリウム及び硝酸ストロンチウムの量を表1(被担持金属酸化物の項)に示す組成となる比率とし、また比較例1の粉末と第2工程の水溶液に含有させる硝酸塩との量比を、該粉末と該硝酸塩に由来する酸化物との質量比が表1の「コア粒子:被担持金属酸化物」の欄に記載の比率になるように調整した。それらの点以外は実施例1と同様とした。
なお、XPS分析により、各実施例で得られた粉末の表層部に存在する酸化物種は、表1に記載の非担持金属酸化物の項に記載のものと同様であることを確認した。またSTEM-EDXによる分析により、各実施例で得られた粉末のコア部に存在する酸化物種は、表1に記載のコア粒子の項に記載のものと同様であることを確認した。
X線光電子分光分析装置として、アルバック・ファイ社製、XPS Quantam2000を使用した。X線源としてAlKα1線(1486.8eV)を使用し、X線照射面積:200μmφ、パスエネルギー:23.5eV、試料と検出器のなす角度15°、測定深さ:数nm、測定間隔:0.1eV、管電圧:15kV、管電流:2.67mA、スキャン回数は各元素10回の条件で行った。なお、データ解析にはアルバック・ファイ社製「マルチパックVer6.1A」を用いた。
<有効Ce率(%)の測定>
各触媒粉末のOSCの測定をCOパルス法で行った。有効Ce率は触媒粉末に含まれるCeが全てCe4+からCe3+に変化する場合のOSC量(μmol-O2)を100%としたときの触媒粉末のOSCの割合として示した。結果を表3に示す。
Pd分散度はCOパルス法で測定したCO吸着量から、触媒に含まれるPdがCOと1:1の割合で吸着するとみなし、算出した。結果を表4に示す。
以上より、本発明の触媒用粉末及びこれに貴金属を担持した触媒が、内燃機関用の排気ガス浄化、特に低中温で発生する排気ガス浄化に優れた効果を発揮することが判る。
以上より、本発明の触媒用粉末及び触媒が、貴金属の触媒活性を高く維持する点でも、内燃機関用の排気ガス浄化、特に低中温で発生する排気ガス浄化用として優れたものであることが判る。
Claims (6)
- セリア及びジルコニアを含むコア部と、該コア部上に位置し、セリア及びジルコニアを含む表層部とを有する触媒用粉末であって、
前記粉末全体のセリウムのモル分率M1(mol%)に対し、X線光電子分光法で測定される前記表層部のセリウムのモル分率M2(mol%)の比(M2/M1)が0.30以上0.95以下である、触媒用粉末。 - セリア及びジルコニアを含むコア粒子と、該コア粒子の表面に担持されたセリア及びジルコニアを含む被担持金属酸化物とを有し、
前記表層部が被担持金属酸化物の少なくとも一部を構成する請求項1に記載の触媒用粉末。 - X線光電子分光法で測定される表層部のジルコニウムのモル分率をM4(mol%)、X線光電子分光法で測定される表層部のセリウムのモル分率をM2(mol%)としたとき、M4と前記M2の比であるM4/2(=M4/M2)が1より大きい請求項1又は2に記載の触媒用粉末。
- 前記粉末全体のジルコニウムのモル分率M3(mol%)と前記粉末全体のセリウムのモル分率M1(mol%)の比をM3/1(=M3/M1)とし、X線光電子分光法で測定されるジルコニウムのモル分率M4(mol%)とX線光電子分光法で測定されるセリウムのモル分率M2(mol%)の比をM4/2(=M4/M2)としたときに前記M3/1とM4/2の比(M4/2/M3/1)が1.1以上5.0以下である、請求項1~3のいずれか1項に記載の触媒用粉末。
- 前記粉末全体の100質量部に対し、セリア以外の希土類元素酸化物及び/又はアルカリ土類金属酸化物を1質量部以上20質量部以下含有する、請求項1~4のいずれか1項に記載の触媒用粉末。
- 請求項1~5のいずれか1項に記載の触媒用粉末と、該触媒用粉末に担持された貴金属とを含有する、排気ガス浄化用触媒。
Priority Applications (5)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP16866309.4A EP3378557A4 (en) | 2015-11-17 | 2016-11-15 | POWDER FOR CATALYSTS, AND CATALYST FOR EXHAUST GAS PURIFICATION |
US15/765,481 US10780423B2 (en) | 2015-11-17 | 2016-11-15 | Powder for catalysts and catalyst for exhaust gas purification |
JP2017551884A JP6695897B2 (ja) | 2015-11-17 | 2016-11-15 | 触媒用粉末及び排気ガス浄化用触媒 |
BR112018007804-2A BR112018007804B1 (pt) | 2015-11-17 | 2016-11-15 | Pó para catalisadores, e, catalisador para purificação de gás de escapamento |
CN201680060733.1A CN108136371B (zh) | 2015-11-17 | 2016-11-15 | 催化剂用粉末及废气净化用催化剂 |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2015225102 | 2015-11-17 | ||
JP2015-225102 | 2015-11-17 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO2017086308A1 true WO2017086308A1 (ja) | 2017-05-26 |
Family
ID=58718925
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/JP2016/083804 WO2017086308A1 (ja) | 2015-11-17 | 2016-11-15 | 触媒用粉末及び排気ガス浄化用触媒 |
Country Status (6)
Country | Link |
---|---|
US (1) | US10780423B2 (ja) |
EP (1) | EP3378557A4 (ja) |
JP (2) | JP6695897B2 (ja) |
CN (1) | CN108136371B (ja) |
BR (1) | BR112018007804B1 (ja) |
WO (1) | WO2017086308A1 (ja) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2021049525A1 (ja) * | 2019-09-10 | 2021-03-18 | 三井金属鉱業株式会社 | セリウム元素及びジルコニウム元素を含有する複合酸化物の粉末、及びこれを使用した排ガス浄化用触媒組成物、並びにその製造方法 |
Citations (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH07171392A (ja) * | 1993-12-20 | 1995-07-11 | Cataler Kogyo Kk | 排気ガス浄化用触媒 |
JP2004243177A (ja) * | 2003-02-12 | 2004-09-02 | Toyota Motor Corp | 排ガス浄化用触媒 |
US20070129246A1 (en) | 2005-04-27 | 2007-06-07 | Masahide Miura | Exhaust gas purifying catalyst and production process thereof |
WO2012105454A1 (ja) * | 2011-02-01 | 2012-08-09 | 株式会社アイシーティー | 排ガス浄化用触媒 |
JP2012245452A (ja) * | 2011-05-26 | 2012-12-13 | Toyota Motor Corp | 排ガス浄化用触媒およびその製造方法 |
US20140038818A1 (en) | 2011-04-22 | 2014-02-06 | Mitsui Mining & Smelting Co., Ltd. | Carrier for internal-combustion engine exhaust gas purification catalyst |
JP2014030801A (ja) | 2012-08-03 | 2014-02-20 | Noritake Co Ltd | 自動車排ガス浄化用助触媒材およびその製造方法 |
JP2015071520A (ja) * | 2013-10-04 | 2015-04-16 | 株式会社豊田中央研究所 | セリア−ジルコニア系複合酸化物及びその製造方法、並びにそのセリア−ジルコニア系複合酸化物を用いた排ガス浄化用触媒 |
Family Cites Families (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP4165441B2 (ja) * | 2004-04-27 | 2008-10-15 | トヨタ自動車株式会社 | 排ガス浄化触媒の製造方法 |
JP4179299B2 (ja) * | 2005-03-23 | 2008-11-12 | トヨタ自動車株式会社 | 触媒担体粉末及び排ガス浄化触媒 |
JP2014114196A (ja) * | 2012-12-12 | 2014-06-26 | Toyota Motor Corp | 複合酸化物材料およびそれを用いた排ガス浄化触媒 |
WO2016143722A1 (en) | 2015-03-12 | 2016-09-15 | Toyota Jidosha Kabushiki Kaisha | Core-shell support, method for producing the same, catalyst for purification of exhaust gas using the core- shell support, method for producing the same, and method for purification of exhaust gas using the catalyst for purification of exhaust gas |
-
2016
- 2016-11-15 JP JP2017551884A patent/JP6695897B2/ja active Active
- 2016-11-15 CN CN201680060733.1A patent/CN108136371B/zh active Active
- 2016-11-15 WO PCT/JP2016/083804 patent/WO2017086308A1/ja unknown
- 2016-11-15 EP EP16866309.4A patent/EP3378557A4/en active Pending
- 2016-11-15 BR BR112018007804-2A patent/BR112018007804B1/pt active IP Right Grant
- 2016-11-15 US US15/765,481 patent/US10780423B2/en active Active
-
2020
- 2020-04-21 JP JP2020075678A patent/JP6869399B2/ja active Active
Patent Citations (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH07171392A (ja) * | 1993-12-20 | 1995-07-11 | Cataler Kogyo Kk | 排気ガス浄化用触媒 |
JP2004243177A (ja) * | 2003-02-12 | 2004-09-02 | Toyota Motor Corp | 排ガス浄化用触媒 |
US20070129246A1 (en) | 2005-04-27 | 2007-06-07 | Masahide Miura | Exhaust gas purifying catalyst and production process thereof |
WO2012105454A1 (ja) * | 2011-02-01 | 2012-08-09 | 株式会社アイシーティー | 排ガス浄化用触媒 |
US20140038818A1 (en) | 2011-04-22 | 2014-02-06 | Mitsui Mining & Smelting Co., Ltd. | Carrier for internal-combustion engine exhaust gas purification catalyst |
JP2012245452A (ja) * | 2011-05-26 | 2012-12-13 | Toyota Motor Corp | 排ガス浄化用触媒およびその製造方法 |
JP2014030801A (ja) | 2012-08-03 | 2014-02-20 | Noritake Co Ltd | 自動車排ガス浄化用助触媒材およびその製造方法 |
JP2015071520A (ja) * | 2013-10-04 | 2015-04-16 | 株式会社豊田中央研究所 | セリア−ジルコニア系複合酸化物及びその製造方法、並びにそのセリア−ジルコニア系複合酸化物を用いた排ガス浄化用触媒 |
Non-Patent Citations (2)
Title |
---|
ATRIBAK, IDRISS ET AL.: "Influence of the physico-chemical properties of CeO2-ZrO2 mixed oxides on the catalytic oxidation of NO to N02", APPLIED SURFACE SCIENCE, vol. 256, 2010, pages 7706 - 7712, XP027167616 * |
See also references of EP3378557A4 |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2021049525A1 (ja) * | 2019-09-10 | 2021-03-18 | 三井金属鉱業株式会社 | セリウム元素及びジルコニウム元素を含有する複合酸化物の粉末、及びこれを使用した排ガス浄化用触媒組成物、並びにその製造方法 |
JP7461364B2 (ja) | 2019-09-10 | 2024-04-03 | 三井金属鉱業株式会社 | セリウム元素及びジルコニウム元素を含有する複合酸化物の粉末、及びこれを使用した排ガス浄化用触媒組成物、並びにその製造方法 |
Also Published As
Publication number | Publication date |
---|---|
CN108136371B (zh) | 2021-09-28 |
EP3378557A4 (en) | 2019-06-26 |
EP3378557A1 (en) | 2018-09-26 |
JP6695897B2 (ja) | 2020-05-20 |
US10780423B2 (en) | 2020-09-22 |
BR112018007804B1 (pt) | 2021-07-20 |
JP6869399B2 (ja) | 2021-05-12 |
CN108136371A (zh) | 2018-06-08 |
BR112018007804A2 (ja) | 2018-10-30 |
JPWO2017086308A1 (ja) | 2018-09-06 |
US20190070590A1 (en) | 2019-03-07 |
JP2020124709A (ja) | 2020-08-20 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
JP3797313B2 (ja) | 金属酸化物粒子の製造法及び排ガス浄化用触媒 | |
CA2562556C (en) | Process for producing metal oxide particle and exhaust gas purifying catalyst | |
JP6676394B2 (ja) | コアシェル担体及びその製造方法、そのコアシェル担体を用いた排ガス浄化用触媒及びその製造方法、並びに、その排ガス浄化用触媒を用いた排ガス浄化方法 | |
JP5526502B2 (ja) | 排気ガス浄化用触媒及びその製造方法 | |
JP4726714B2 (ja) | 無機酸化物、及びそれを用いた排ガス浄化用触媒 | |
JP6869399B2 (ja) | 触媒用粉末及び排気ガス浄化用触媒 | |
JP2005254047A (ja) | 排ガス浄化触媒並びに、金属酸化物粒子及びその製造方法 | |
JP7213822B2 (ja) | 排ガス浄化用組成物 | |
JP2011092859A (ja) | 酸素吸放出材及びそれを含む排ガス浄化用触媒 | |
JP2006298759A (ja) | 排ガス浄化用触媒 | |
JP2006043683A (ja) | 触媒担体及びその製造方法、並びに排ガス浄化触媒 | |
WO2015174102A1 (ja) | 排ガス浄化用触媒 | |
JP6824051B2 (ja) | 複合酸化物、及びその酸素貯蔵能の評価方法 | |
JP7329060B2 (ja) | 排気ガス浄化用触媒、排気ガスの浄化方法、及び排気ガス浄化用触媒の製造方法 | |
JP6824467B2 (ja) | 排ガス浄化用触媒 | |
WO2015173880A1 (ja) | 水素生成用触媒及び排ガス浄化用触媒 | |
JP7086196B2 (ja) | 排ガス浄化触媒用組成物及びそれを用いた排ガス浄化触媒 | |
EP4219002A1 (en) | Doped ceria-zirconia having increased stability to disordering | |
JP2003144923A (ja) | 排気ガス浄化用触媒 | |
US11084022B2 (en) | Pd-supporting Zr-based composite oxide | |
JP2016140809A (ja) | 排ガス浄化用触媒 | |
EP2177258B1 (en) | Exhaust gas purification catalyst | |
JP2018075550A (ja) | 排ガス浄化用三元触媒及びその製造方法、並びに排ガス浄化用触媒コンバータ | |
JP2024000368A (ja) | 排ガス浄化用触媒 | |
JP2014147877A (ja) | 排ガス浄化用触媒 |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
121 | Ep: the epo has been informed by wipo that ep was designated in this application |
Ref document number: 16866309 Country of ref document: EP Kind code of ref document: A1 |
|
ENP | Entry into the national phase |
Ref document number: 2017551884 Country of ref document: JP Kind code of ref document: A |
|
REG | Reference to national code |
Ref country code: BR Ref legal event code: B01A Ref document number: 112018007804 Country of ref document: BR |
|
NENP | Non-entry into the national phase |
Ref country code: DE |
|
ENP | Entry into the national phase |
Ref document number: 112018007804 Country of ref document: BR Kind code of ref document: A2 Effective date: 20180418 |