US20110076202A1 - Particulate combustion catalyst, particulate filter and exhaust gas purifying apparatus - Google Patents
Particulate combustion catalyst, particulate filter and exhaust gas purifying apparatus Download PDFInfo
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- US20110076202A1 US20110076202A1 US12/994,504 US99450408A US2011076202A1 US 20110076202 A1 US20110076202 A1 US 20110076202A1 US 99450408 A US99450408 A US 99450408A US 2011076202 A1 US2011076202 A1 US 2011076202A1
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- Prior art keywords
- particulate
- combustion catalyst
- catalyst
- carrier
- mass
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- 239000003054 catalyst Substances 0.000 title claims abstract description 135
- 238000002485 combustion reaction Methods 0.000 title claims abstract description 75
- RVTZCBVAJQQJTK-UHFFFAOYSA-N oxygen(2-);zirconium(4+) Chemical compound [O-2].[O-2].[Zr+4] RVTZCBVAJQQJTK-UHFFFAOYSA-N 0.000 claims abstract description 38
- 229910001928 zirconium oxide Inorganic materials 0.000 claims abstract description 38
- 229910052709 silver Inorganic materials 0.000 claims abstract description 32
- 239000002245 particle Substances 0.000 claims abstract description 18
- 238000004140 cleaning Methods 0.000 claims abstract description 11
- 238000010304 firing Methods 0.000 claims description 16
- 230000000977 initiatory effect Effects 0.000 claims description 8
- 230000000052 comparative effect Effects 0.000 description 16
- 239000007789 gas Substances 0.000 description 13
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 12
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Substances [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 11
- 229910052593 corundum Inorganic materials 0.000 description 10
- 238000007254 oxidation reaction Methods 0.000 description 10
- 229910001845 yogo sapphire Inorganic materials 0.000 description 10
- 230000003647 oxidation Effects 0.000 description 8
- SQGYOTSLMSWVJD-UHFFFAOYSA-N silver(1+) nitrate Chemical compound [Ag+].[O-]N(=O)=O SQGYOTSLMSWVJD-UHFFFAOYSA-N 0.000 description 8
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 7
- 238000006243 chemical reaction Methods 0.000 description 6
- 239000011369 resultant mixture Substances 0.000 description 5
- 239000000243 solution Substances 0.000 description 5
- 239000004071 soot Substances 0.000 description 5
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 5
- 238000001035 drying Methods 0.000 description 4
- 230000000694 effects Effects 0.000 description 4
- 238000010438 heat treatment Methods 0.000 description 4
- 239000000203 mixture Substances 0.000 description 4
- 239000013618 particulate matter Substances 0.000 description 4
- 238000011069 regeneration method Methods 0.000 description 4
- 239000004332 silver Substances 0.000 description 4
- 229910001961 silver nitrate Inorganic materials 0.000 description 4
- 239000002002 slurry Substances 0.000 description 4
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 3
- 239000011230 binding agent Substances 0.000 description 3
- 239000011248 coating agent Substances 0.000 description 3
- 238000000576 coating method Methods 0.000 description 3
- 238000000034 method Methods 0.000 description 3
- 229910000510 noble metal Inorganic materials 0.000 description 3
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 description 2
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 2
- 229910052799 carbon Inorganic materials 0.000 description 2
- 230000003197 catalytic effect Effects 0.000 description 2
- 229910052681 coesite Inorganic materials 0.000 description 2
- 229910052906 cristobalite Inorganic materials 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 229910052760 oxygen Inorganic materials 0.000 description 2
- 239000001301 oxygen Substances 0.000 description 2
- 229910052763 palladium Inorganic materials 0.000 description 2
- 229910052697 platinum Inorganic materials 0.000 description 2
- 239000010453 quartz Substances 0.000 description 2
- 230000008929 regeneration Effects 0.000 description 2
- 239000000377 silicon dioxide Substances 0.000 description 2
- 229910052682 stishovite Inorganic materials 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 229910052905 tridymite Inorganic materials 0.000 description 2
- 229910052684 Cerium Inorganic materials 0.000 description 1
- 229910002060 Fe-Cr-Al alloy Inorganic materials 0.000 description 1
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 1
- 239000012494 Quartz wool Substances 0.000 description 1
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 description 1
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 1
- QCWXUUIWCKQGHC-UHFFFAOYSA-N Zirconium Chemical compound [Zr] QCWXUUIWCKQGHC-UHFFFAOYSA-N 0.000 description 1
- 238000003915 air pollution Methods 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 239000007864 aqueous solution Substances 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 229910010293 ceramic material Inorganic materials 0.000 description 1
- GWXLDORMOJMVQZ-UHFFFAOYSA-N cerium Chemical compound [Ce] GWXLDORMOJMVQZ-UHFFFAOYSA-N 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 229910052878 cordierite Inorganic materials 0.000 description 1
- 239000010987 cubic zirconia Substances 0.000 description 1
- JSKIRARMQDRGJZ-UHFFFAOYSA-N dimagnesium dioxido-bis[(1-oxido-3-oxo-2,4,6,8,9-pentaoxa-1,3-disila-5,7-dialuminabicyclo[3.3.1]nonan-7-yl)oxy]silane Chemical compound [Mg++].[Mg++].[O-][Si]([O-])(O[Al]1O[Al]2O[Si](=O)O[Si]([O-])(O1)O2)O[Al]1O[Al]2O[Si](=O)O[Si]([O-])(O1)O2 JSKIRARMQDRGJZ-UHFFFAOYSA-N 0.000 description 1
- 239000006185 dispersion Substances 0.000 description 1
- 238000011156 evaluation Methods 0.000 description 1
- 239000000835 fiber Substances 0.000 description 1
- 239000006260 foam Substances 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000003801 milling Methods 0.000 description 1
- 239000004570 mortar (masonry) Substances 0.000 description 1
- 229910017604 nitric acid Inorganic materials 0.000 description 1
- 230000001590 oxidative effect Effects 0.000 description 1
- WHOPEPSOPUIRQQ-UHFFFAOYSA-N oxoaluminum Chemical compound O1[Al]O[Al]1 WHOPEPSOPUIRQQ-UHFFFAOYSA-N 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- 229940100890 silver compound Drugs 0.000 description 1
- 150000003379 silver compounds Chemical class 0.000 description 1
- 238000005245 sintering Methods 0.000 description 1
- 229910001256 stainless steel alloy Inorganic materials 0.000 description 1
- 229910052719 titanium Inorganic materials 0.000 description 1
- 239000010936 titanium Substances 0.000 description 1
- 238000011144 upstream manufacturing Methods 0.000 description 1
- 229910052720 vanadium Inorganic materials 0.000 description 1
- LEONUFNNVUYDNQ-UHFFFAOYSA-N vanadium atom Chemical compound [V] LEONUFNNVUYDNQ-UHFFFAOYSA-N 0.000 description 1
- 229910052726 zirconium Inorganic materials 0.000 description 1
Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D39/00—Filtering material for liquid or gaseous fluids
- B01D39/14—Other self-supporting filtering material ; Other filtering material
- B01D39/20—Other self-supporting filtering material ; Other filtering material of inorganic material, e.g. asbestos paper, metallic filtering material of non-woven wires
- B01D39/2068—Other inorganic materials, e.g. ceramics
-
- 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
- B01D53/944—Simultaneously removing carbon monoxide, hydrocarbons or carbon making use of oxidation catalysts
-
- 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
- B01D53/96—Regeneration, reactivation or recycling of reactants
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J21/00—Catalysts comprising the elements, oxides, or hydroxides of magnesium, boron, aluminium, carbon, silicon, titanium, zirconium, or hafnium
- B01J21/06—Silicon, titanium, zirconium or hafnium; Oxides or hydroxides thereof
- B01J21/066—Zirconium or hafnium; Oxides or hydroxides thereof
-
- 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
- B01J23/48—Silver or gold
- B01J23/50—Silver
-
- B01J35/612—
-
- B01J35/613—
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
- B01J37/08—Heat treatment
-
- 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
- F01N3/02—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust
- F01N3/021—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters
- F01N3/033—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters in combination with other devices
- F01N3/035—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters in combination with other devices with catalytic reactors, e.g. catalysed diesel particulate filters
-
- 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
- B01D2255/104—Silver
-
- 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
- B01D2255/92—Dimensions
- B01D2255/9207—Specific surface
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2258/00—Sources of waste gases
- B01D2258/01—Engine exhaust gases
- B01D2258/012—Diesel engines and lean burn gasoline engines
-
- 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
Definitions
- the present invention relates to a particulate combustion catalyst, to a particulate filter, and to an exhaust gas cleaning apparatus. More particularly, the present invention relates to a particulate combustion catalyst which realizes, at low temperature, removal (through oxidation) of particulate matter discharged from a diesel internal combustion engine; to a particulate filter coated with the particulate combustion catalyst; and to an exhaust gas cleaning apparatus including the particulate filter coated with the particulate combustion catalyst.
- Exhaust gas discharged from diesel engines contains particulates (i.e., particulate matter), and release of such a substance into the atmosphere without any treatment is a main cause of air pollution. Therefore, demand has arisen for strict regulation for such a substance.
- a flow-through oxidation catalyst for combustion of soluble organic fractions (SOFs) or a diesel exhaust gas trapping system employing a diesel particulate filter (DPF) for trapping soot.
- DPF diesel particulate filter
- Hitherto proposed continuous regeneration systems include a system employing a catalyst including a carrier made of, for example, an oxide of a metal (e.g., aluminum, zirconium, cerium, titanium, or vanadium) or a composite oxide, and an expensive noble metal (e.g., Pt) supported on the carrier (see, for example, Patent Document 1, 2, or 3); and a continuous regeneration method involving NO 2 (see, for example, Patent Document 4).
- This continuous regeneration method requires provision, upstream of a DPF, of an oxidation catalyst (e.g., Pt) for oxidizing NO into NO 2 , and thus involves high cost.
- reaction involving NO 2 is affected by the ratio of NO x to C, and many restrictions are imposed on the employment of this method.
- Patent Document 1 Japanese Patent Application Laid-Open (kokai) No. H10-047035
- Patent Document 2 Japanese Patent Application Laid-Open (kokai) No. 2003-334443
- Patent Document 3 Japanese Patent Application Laid-Open (kokai) No. 2004-058013
- Patent Document 4 Japanese Patent No. 3012249
- An object of the present invention is to provide a particulate combustion catalyst which realizes removal of soot through oxidation at low temperature without employment of an expensive noble metal, and which enables oxidation reaction to proceed with the aid of only oxygen and thus realizes removal of soot through oxidation at low temperature regardless of the NO x concentration of exhaust gas.
- Another object of the present invention is to provide a particulate filter coated with the particulate combustion catalyst.
- Yet another object of the present invention is to provide an exhaust gas cleaning apparatus comprising the particulate filter coated with the particulate combustion catalyst.
- the present inventors have conducted extensive studies, and as a result have found that the objects can be achieved by providing a particulate combustion catalyst including specific zirconium oxide particles serving as a carrier, and metallic Ag or Ag oxide serving as a catalyst component, the catalyst component being supported on the carrier, wherein the amount of the catalyst component falls within a specific range, and preferably, the catalyst has a BET specific surface area falling within a specific range.
- the present invention has been accomplished on the basis of this finding.
- the present invention provides a particulate combustion catalyst characterized by comprising a carrier formed of monoclinic zirconium oxide particles, and metallic Ag or Ag oxide, which serves as a catalyst component and is supported on the carrier, wherein the amount of the catalyst component is 0.5 to 10 mass %, as reduced to metallic Ag, on the basis of the mass of the carrier.
- the particulate combustion catalyst of the present invention comprises a carrier formed of monoclinic zirconium oxide particles, and metallic Ag or Ag oxide, which serves as a catalyst component and is supported on the carrier, wherein the amount of the catalyst component is 0.5 to 10 mass %, as reduced to metallic Ag, on the basis of the mass of the carrier, and the catalyst has a BET specific surface area of 8 to 21 m 2 /g.
- the particulate combustion catalyst of the present invention comprises a carrier formed of monoclinic zirconium oxide particles, and metallic Ag or Ag oxide, which serves as a catalyst component and is supported on the carrier, wherein the amount of the catalyst component is 1 to 9 mass %, as reduced to metallic Ag, on the basis of the mass of the carrier, and the catalyst has a BET specific surface area of 11 to 20 m 2 /g.
- the present invention also provides a particulate filter characterized by being coated with any of the aforementioned particulate combustion catalysts.
- the present invention also provides an exhaust gas cleaning apparatus characterized by comprising a particulate filter coated with any of the aforementioned particulate combustion catalysts.
- particulate combustion catalyst of the present invention realizes removal of soot through oxidation at low temperature without use of an expensive noble metal.
- soot can be removed through oxidation at low temperature regardless of the NO x concentration of exhaust gas.
- the particulate combustion catalyst of the present invention includes a carrier formed of monoclinic zirconium oxide particles, and metallic Ag or Ag oxide, which serves as a catalyst component and is supported on the carrier.
- a carrier formed of monoclinic zirconium oxide particles, and metallic Ag or Ag oxide, which serves as a catalyst component and is supported on the carrier.
- zirconium oxide e.g., monoclinic zirconium oxide and stabilized cubic zirconium oxide
- the particulate combustion catalyst of the present invention employs monoclinic zirconium oxide as a carrier.
- metallic Ag or Ag oxide In the particulate combustion catalyst of the present invention, metallic Ag or Ag oxide must be supported, as a catalyst component, on the aforementioned carrier.
- Metallic Ag or Ag oxide, which is employed in the present invention is less expensive than, for example, Pt or Pd.
- the amount of metallic Ag or Ag oxide supported on the carrier is 0.5 to 10 mass % (preferably, 1 to 9 mass %), as reduced to metallic Ag, on the basis of the mass of the carrier.
- the catalyst component When the amount of the catalyst component supported is less than 0.5 mass %, the catalyst component may fail to sufficiently exhibit its catalytic effects, and Tig (combustion initiation temperature) becomes higher than 300° C. Even when the amount of the catalyst component supported exceeds 10 mass %, effects commensurate with such a large catalyst component amount cannot be attained. In addition, when the amount of the catalyst component is large, sintering of metal is likely to occur, and the catalyst component is not expected to exhibit its catalytic effects. When the amount of the catalyst component supported is 1 to 9 mass %, as reduced to metallic Ag, on the basis of the mass of the carrier, and the catalyst has a BET specific surface area of 11 to 20 m 2 /g, Tig becomes 260° C. or lower, although the reason for this has not been elucidated.
- the particulate combustion catalyst of the present invention preferably has a BET specific surface area of 8 to 21 m 2 /g, more preferably 11 to 20 m 2 /g.
- a BET specific surface area of 8 to 21 m 2 /g When the catalyst has a BET specific surface area of less than 8 m 2 /g, Tig tends to become higher than 300° C., whereas when the catalyst has a BET specific surface area in excess of 21 m 2 /g, Tig also tends to become higher than 300° C.
- the catalyst has a BET specific surface area of 11 to 20 m 2 /g, and the amount of the catalyst component supported is 1 to 9 mass %, as reduced to metallic Ag, on the basis of the mass of the carrier, Tig becomes 260° C. or lower.
- a particulate combustion catalyst including a carrier and a catalyst component whose amount is 0.5 to 10 mass %, as reduced to metallic Ag, on the basis of the mass of the carrier exhibits a sufficiently low Tig
- a particulate combustion catalyst including a carrier and a catalyst component whose amount is 1 to 9 mass %, as reduced to metallic Ag, on the basis of the mass of the carrier, and having a BET specific surface area of 11 to 20 m 2 /g exhibits a Tig of 260° C. or lower.
- the particulate filter of the present invention is produced by causing the particulate combustion catalyst of the present invention to be held on a base, preferably, the surface of the carrier is provided with a binder component such as SiO 2 , TiO 2 , ZrO 2 , or Al 2 O 2 .
- a binder component such as SiO 2 , TiO 2 , ZrO 2 , or Al 2 O 2 .
- the particulate combustion catalyst of the present invention may be produced through, for example, the following process.
- the aforementioned monoclinic zirconium oxide particles are mixed with a binder component (e.g., SiO 2 or alumina sol) and water, and optionally, the resultant mixture is finely milled by means of a milling apparatus (e.g., a ball mill).
- a milling apparatus e.g., a ball mill.
- the resultant dispersion is mixed with an aqueous solution of a water-soluble silver compound, and the mixture is thoroughly stirred, to thereby prepare a slurry.
- the slurry is dried, and the catalyst-component-supported monoclinic zirconium oxide particles are fired generally at 600 to 900° C., preferably at 730 to 870° C., more preferably at 750 to 850° C. for 10 hours or longer (generally, about 20 hours).
- the firing temperature is lower than 600° C., the resultant catalyst tends to have large BET specific surface area and to exhibit high Tig, whereas when the firing temperature exceeds 900° C., the resultant catalyst tends to have small BET specific surface area and to exhibit high Tig (i.e., a practical product is less likely to be produced).
- the resultant catalyst tends to have a BET specific surface area of about 8 to about 21 m 2 /g and to exhibit a Tig of 300° C. or lower, whereas when the firing temperature is 730 to 870° C., the resultant catalyst tends to have a BET specific surface area of about 11 to about 20 m 2 /g and to exhibit a Tig of 260° C. or lower.
- the firing time is shorter than 10 hours, a catalyst having intended characteristics may fail to be produced, whereas even when the firing time exceeds 50 hours, effects commensurate with such a long firing time are not obtained.
- the particulate filter of the present invention may assume any known form of particulate filter, but preferably has a three-dimensional structure.
- filters having a three-dimensional structure include a wall-through filter, a flow-through honeycomb filter, a wire mesh filter, a ceramic fiber filter, a metallic porous filter, a particle-charged filter, and a foam filter.
- the material of the base include ceramic materials such as cordierite and SiC; Fe—Cr—Al alloys; and stainless steel alloys.
- the exhaust gas cleaning apparatus of the present invention which includes therein the aforementioned particulate filter of the present invention, will be readily appreciated by those skilled in the art.
- a base filter e.g., a wire mesh filter
- the slurry-coated filter is fired generally at 600 to 900° C., preferably at 730 to 870° C., more preferably at 750 to 850° C. for 10 hours or longer (generally, about 20 hours).
- the total catalyst coating amount is preferably 10 to 100 g/L (for a wall-flow DPF) or about 50 to about 150 g/L (for a wire mesh DPF).
- the Tig (combustion initiation temperature) of a powdery catalyst was determined through the following method.
- Particulate combustion catalyst powder (20 mg) and carbon (Printex-V (toner carbon), product of Degussa) (2 mg) were mixed for two minutes by means of an agate mortar, and the mixture was fixed at a center portion of a quartz reaction tube by use of quartz wool. While a circulation gas having the below-described composition was caused to flow through the quartz reaction tube at the below-described flow rate, the temperature of the reaction tube was elevated at the below-described temperature elevation rate by means of an electric furnace, and CO and CO 2 concentrations were measured at the outlet of the reaction tube by means of an infrared analyzer. The temperature as measured at the inlet of the catalyst-containing reaction tube when CO 2 concentration reached 30 ppm (i.e., electric furnace control temperature) was regarded as Tig (combustion initiation temperature).
- Monoclinic zirconium oxide (ZrO 2 ) particles or ⁇ -alumina (Al 2 O 3 ) particles were employed as a carrier.
- the powdery carrier was mixed with aqueous silver nitrate solution or nitric acid solution of (dinitrodiamine)Pt so that the amount of a catalyst component supported (as reduced to metallic silver or metallic platinum) on the basis of the mass of the carrier was adjusted as shown in Table 1.
- the resultant mixture was stirred for one hour. Thereafter, water was evaporated under heating, followed by drying at 120° C.
- the thus-dried product was fired at 750° C. for 20 hours, to thereby produce a particulate combustion catalyst.
- Table 1 shows the BET specific surface area and Tig of the particulate combustion catalyst.
- Example 1 Catalyst com- Amount BET specific Carrier ponent supported surface area Tig Comparative ZrO 2 Ag 0 mass % 25.6 m 2 /g 384° C.
- Example 1 ZrO 2 Ag 0.5 mass % 20.7 m 2 /g 300° C.
- Example 2 ZrO 2 Ag 1 mass % 19.2 m 2 /g 251° C.
- Example 3 ZrO 2 Ag 2 mass % 16.0 m 2 /g 245° C.
- Example 4 ZrO 2 Ag 5 mass % 15.3 m 2 /g 256° C.
- Example 6 ZrO 2 Ag 10 mass % 10.2 m 2 /g 264° C. Comparative Al 2 O 3 Ag 0 mass % 147.8 m 2 /g 479° C. Example 2 Comparative Al 2 O 3 Ag 1 mass % 146.9 m 2 /g 487° C. Example 3 Comparative Al 2 O 3 Ag 2 mass % 146.4 m 2 /g 476° C. Example 4 Comparative Al 2 O 3 Ag 5 mass % 136.8 m 2 /g 441° C. Example 5 Comparative Al 2 O 3 Pt 0 mass % 147.8 m 2 /g 479° C. Example 6 Comparative Al 2 O 3 Pt 1 mass % 142.8 m 2 /g 458° C. Example 7 Comparative Al 2 O 3 Pt 2 mass % 151.2 m 2 /g 459° C. Example 8 Comparative Al 2 O 3 Pt 5 mass % 147.8 m 2 /g 461° C. Example 9
- Monoclinic zirconium oxide (ZrO 2 ) particles were employed as a carrier.
- the powdery carrier was mixed with an aqueous silver nitrate solution so that the amount of a catalyst component supported (as reduced to metallic silver) on the basis of the mass of the carrier was adjusted as shown in Table 2.
- the resultant mixture was stirred for one hour. Thereafter, water was evaporated under heating, followed by drying at 120° C. The thus-dried product was fired at 750° C. for 20 hours, to thereby produce a particulate combustion catalyst.
- Table 2 shows the BET specific surface area and Tig of the particulate combustion catalyst.
- Monoclinic zirconium oxide particles were employed as a carrier.
- the powdery carrier was mixed with an aqueous silver nitrate solution so that the amount of a catalyst component supported (as reduced to metallic silver) was adjusted to 1 mass % on the basis of the mass of the carrier, and the resultant mixture was stirred for one hour. Thereafter, water was evaporated under heating, followed by drying at 120° C. The thus-dried product was fired at a temperature shown in Table 3 for 20 hours, to thereby produce a particulate combustion catalyst.
- Table 3 shows the BET specific surface area and Tig of the particulate combustion catalyst.
- Example 12 600° C. 27.5 m 2 /g 277° C.
- Example 13 650° C. 23.2 m 2 /g 268° C.
- Example 14 700° C. 21.1 m 2 /g 271° C.
- Example 15 750° C. 19.2 m 2 /g 251° C.
- Example 16 800° C. 13.9 m 2 /g 259° C.
- Example 17 850° C. 11.9 m 2 /g 252° C.
- Example 18 900° C. 6.2 m 2 /g 275° C.
- Monoclinic zirconium oxide particles were employed as a carrier.
- the powdery carrier was mixed with an aqueous silver nitrate solution so that the amount of a catalyst component supported (as reduced to metallic silver) was adjusted to 1 mass % on the basis of the mass of the carrier, and the resultant mixture was stirred for one hour. Thereafter, water was evaporated under heating, followed by drying at 120° C. The thus-dried product was fired at 750° C. for a period of time shown in Table 4, to thereby produce a particulate combustion catalyst.
- Table 4 shows the BET specific surface area and Tig of the particulate combustion catalyst.
- Example 19 10 hours 19.1 m 2 /g 259° C.
- Example 20 15 hours 18.0 m 2 /g 256° C.
- Example 21 20 hours 19.2 m 2 /g 251° C.
- Example 22 25 hours 15.1 m 2 /g 254° C.
- Example 23 30 hours 14.7 m 2 /g 255° C.
- Example 24 50 hours 12.9 m 2 /g 258° C.
Abstract
Provided is a particulate combustion catalyst including a carrier formed of monoclinic zirconium oxide particles, and metallic Ag or Ag oxide, which serves as a catalyst component and is supported on the carrier, wherein the amount of the catalyst component is 0.5 to 10 mass %, as reduced to metallic Ag, on the basis of the mass of the carrier, and preferably, the catalyst has a BET specific surface area of 8 to 21 m2/g. Also provided are a particulate filter coated with the particulate combustion catalyst; and an exhaust gas cleaning apparatus including a particulate filter coated with the particulate combustion catalyst.
Description
- The present invention relates to a particulate combustion catalyst, to a particulate filter, and to an exhaust gas cleaning apparatus. More particularly, the present invention relates to a particulate combustion catalyst which realizes, at low temperature, removal (through oxidation) of particulate matter discharged from a diesel internal combustion engine; to a particulate filter coated with the particulate combustion catalyst; and to an exhaust gas cleaning apparatus including the particulate filter coated with the particulate combustion catalyst.
- Exhaust gas discharged from diesel engines contains particulates (i.e., particulate matter), and release of such a substance into the atmosphere without any treatment is a main cause of air pollution. Therefore, demand has arisen for strict regulation for such a substance. There has been proposed, as effective means for removing particulate matter, a flow-through oxidation catalyst for combustion of soluble organic fractions (SOFs), or a diesel exhaust gas trapping system employing a diesel particulate filter (DPF) for trapping soot. However, for regeneration of such a DPF, particulate matter trapped therein must be continuously removed through oxidation.
- Hitherto proposed continuous regeneration systems include a system employing a catalyst including a carrier made of, for example, an oxide of a metal (e.g., aluminum, zirconium, cerium, titanium, or vanadium) or a composite oxide, and an expensive noble metal (e.g., Pt) supported on the carrier (see, for example, Patent Document 1, 2, or 3); and a continuous regeneration method involving NO2 (see, for example, Patent Document 4). This continuous regeneration method requires provision, upstream of a DPF, of an oxidation catalyst (e.g., Pt) for oxidizing NO into NO2, and thus involves high cost. In addition, reaction involving NO2 is affected by the ratio of NOx to C, and many restrictions are imposed on the employment of this method.
- Patent Document 1: Japanese Patent Application Laid-Open (kokai) No. H10-047035
Patent Document 2: Japanese Patent Application Laid-Open (kokai) No. 2003-334443
Patent Document 3: Japanese Patent Application Laid-Open (kokai) No. 2004-058013 - An object of the present invention is to provide a particulate combustion catalyst which realizes removal of soot through oxidation at low temperature without employment of an expensive noble metal, and which enables oxidation reaction to proceed with the aid of only oxygen and thus realizes removal of soot through oxidation at low temperature regardless of the NOx concentration of exhaust gas. Another object of the present invention is to provide a particulate filter coated with the particulate combustion catalyst. Yet another object of the present invention is to provide an exhaust gas cleaning apparatus comprising the particulate filter coated with the particulate combustion catalyst.
- In order to achieve the aforementioned objects, the present inventors have conducted extensive studies, and as a result have found that the objects can be achieved by providing a particulate combustion catalyst including specific zirconium oxide particles serving as a carrier, and metallic Ag or Ag oxide serving as a catalyst component, the catalyst component being supported on the carrier, wherein the amount of the catalyst component falls within a specific range, and preferably, the catalyst has a BET specific surface area falling within a specific range. The present invention has been accomplished on the basis of this finding.
- Accordingly, the present invention provides a particulate combustion catalyst characterized by comprising a carrier formed of monoclinic zirconium oxide particles, and metallic Ag or Ag oxide, which serves as a catalyst component and is supported on the carrier, wherein the amount of the catalyst component is 0.5 to 10 mass %, as reduced to metallic Ag, on the basis of the mass of the carrier.
- Preferably, the particulate combustion catalyst of the present invention comprises a carrier formed of monoclinic zirconium oxide particles, and metallic Ag or Ag oxide, which serves as a catalyst component and is supported on the carrier, wherein the amount of the catalyst component is 0.5 to 10 mass %, as reduced to metallic Ag, on the basis of the mass of the carrier, and the catalyst has a BET specific surface area of 8 to 21 m2/g.
- More preferably, the particulate combustion catalyst of the present invention comprises a carrier formed of monoclinic zirconium oxide particles, and metallic Ag or Ag oxide, which serves as a catalyst component and is supported on the carrier, wherein the amount of the catalyst component is 1 to 9 mass %, as reduced to metallic Ag, on the basis of the mass of the carrier, and the catalyst has a BET specific surface area of 11 to 20 m2/g.
- The present invention also provides a particulate filter characterized by being coated with any of the aforementioned particulate combustion catalysts. The present invention also provides an exhaust gas cleaning apparatus characterized by comprising a particulate filter coated with any of the aforementioned particulate combustion catalysts.
- Employment of the particulate combustion catalyst of the present invention realizes removal of soot through oxidation at low temperature without use of an expensive noble metal. When the particulate combustion catalyst is employed, since oxidation reaction proceeds with the aid of only oxygen, soot can be removed through oxidation at low temperature regardless of the NOx concentration of exhaust gas.
- The particulate combustion catalyst of the present invention includes a carrier formed of monoclinic zirconium oxide particles, and metallic Ag or Ag oxide, which serves as a catalyst component and is supported on the carrier. Although various types of zirconium oxide (e.g., monoclinic zirconium oxide and stabilized cubic zirconium oxide) are commercially available, the particulate combustion catalyst of the present invention employs monoclinic zirconium oxide as a carrier.
- In the particulate combustion catalyst of the present invention, metallic Ag or Ag oxide must be supported, as a catalyst component, on the aforementioned carrier. Metallic Ag or Ag oxide, which is employed in the present invention, is less expensive than, for example, Pt or Pd. In addition, when metallic Ag or Ag oxide is employed in combination with a specific carrier used in the present invention, further excellent effects are obtained, as compared with the case where a Pt or Pd component is employed. In the present invention, the amount of metallic Ag or Ag oxide supported on the carrier is 0.5 to 10 mass % (preferably, 1 to 9 mass %), as reduced to metallic Ag, on the basis of the mass of the carrier. When the amount of the catalyst component supported is less than 0.5 mass %, the catalyst component may fail to sufficiently exhibit its catalytic effects, and Tig (combustion initiation temperature) becomes higher than 300° C. Even when the amount of the catalyst component supported exceeds 10 mass %, effects commensurate with such a large catalyst component amount cannot be attained. In addition, when the amount of the catalyst component is large, sintering of metal is likely to occur, and the catalyst component is not expected to exhibit its catalytic effects. When the amount of the catalyst component supported is 1 to 9 mass %, as reduced to metallic Ag, on the basis of the mass of the carrier, and the catalyst has a BET specific surface area of 11 to 20 m2/g, Tig becomes 260° C. or lower, although the reason for this has not been elucidated.
- The particulate combustion catalyst of the present invention preferably has a BET specific surface area of 8 to 21 m2/g, more preferably 11 to 20 m2/g. When the catalyst has a BET specific surface area of less than 8 m2/g, Tig tends to become higher than 300° C., whereas when the catalyst has a BET specific surface area in excess of 21 m2/g, Tig also tends to become higher than 300° C. As described above, when the catalyst has a BET specific surface area of 11 to 20 m2/g, and the amount of the catalyst component supported is 1 to 9 mass %, as reduced to metallic Ag, on the basis of the mass of the carrier, Tig becomes 260° C. or lower.
- As shown in the Examples and Comparative Examples described hereinbelow, a particulate combustion catalyst including a carrier and a catalyst component whose amount is 0.5 to 10 mass %, as reduced to metallic Ag, on the basis of the mass of the carrier exhibits a sufficiently low Tig, whereas a particulate combustion catalyst including a carrier and a catalyst component whose amount is 1 to 9 mass %, as reduced to metallic Ag, on the basis of the mass of the carrier, and having a BET specific surface area of 11 to 20 m2/g exhibits a Tig of 260° C. or lower.
- In consideration that the particulate filter of the present invention is produced by causing the particulate combustion catalyst of the present invention to be held on a base, preferably, the surface of the carrier is provided with a binder component such as SiO2, TiO2, ZrO2, or Al2O2. When such a binder component is provided on the surface of the carrier, adhesion between the base and the carrier is enhanced, and the catalyst exhibits improved durability and heat resistance.
- The particulate combustion catalyst of the present invention may be produced through, for example, the following process. The aforementioned monoclinic zirconium oxide particles are mixed with a binder component (e.g., SiO2 or alumina sol) and water, and optionally, the resultant mixture is finely milled by means of a milling apparatus (e.g., a ball mill). The resultant dispersion is mixed with an aqueous solution of a water-soluble silver compound, and the mixture is thoroughly stirred, to thereby prepare a slurry. Thereafter, the slurry is dried, and the catalyst-component-supported monoclinic zirconium oxide particles are fired generally at 600 to 900° C., preferably at 730 to 870° C., more preferably at 750 to 850° C. for 10 hours or longer (generally, about 20 hours). When the firing temperature is lower than 600° C., the resultant catalyst tends to have large BET specific surface area and to exhibit high Tig, whereas when the firing temperature exceeds 900° C., the resultant catalyst tends to have small BET specific surface area and to exhibit high Tig (i.e., a practical product is less likely to be produced). When the firing temperature is 600 to 900° C., the resultant catalyst tends to have a BET specific surface area of about 8 to about 21 m2/g and to exhibit a Tig of 300° C. or lower, whereas when the firing temperature is 730 to 870° C., the resultant catalyst tends to have a BET specific surface area of about 11 to about 20 m2/g and to exhibit a Tig of 260° C. or lower. When the firing time is shorter than 10 hours, a catalyst having intended characteristics may fail to be produced, whereas even when the firing time exceeds 50 hours, effects commensurate with such a long firing time are not obtained.
- The particulate filter of the present invention may assume any known form of particulate filter, but preferably has a three-dimensional structure. Specific examples of filters having a three-dimensional structure include a wall-through filter, a flow-through honeycomb filter, a wire mesh filter, a ceramic fiber filter, a metallic porous filter, a particle-charged filter, and a foam filter. Examples of the material of the base include ceramic materials such as cordierite and SiC; Fe—Cr—Al alloys; and stainless steel alloys.
- The exhaust gas cleaning apparatus of the present invention, which includes therein the aforementioned particulate filter of the present invention, will be readily appreciated by those skilled in the art.
- Next will be described a method for producing the particulate filter of the present invention. A base filter (e.g., a wire mesh filter) is coated with a slurry prepared as described above. The slurry-coated filter is fired generally at 600 to 900° C., preferably at 730 to 870° C., more preferably at 750 to 850° C. for 10 hours or longer (generally, about 20 hours). The total catalyst coating amount is preferably 10 to 100 g/L (for a wall-flow DPF) or about 50 to about 150 g/L (for a wire mesh DPF). When the total catalyst coating amount is excessively small, sufficient performance fails to be attained, whereas when the total catalyst coating amount is excessively large, back pressure to exhaust gas increases.
- The present invention will next be described in detail with reference to Examples and Comparative Examples.
- In the below-described Examples and Comparative Examples, the Tig (combustion initiation temperature) of a powdery catalyst was determined through the following method.
- Particulate combustion catalyst powder (20 mg) and carbon (Printex-V (toner carbon), product of Degussa) (2 mg) were mixed for two minutes by means of an agate mortar, and the mixture was fixed at a center portion of a quartz reaction tube by use of quartz wool. While a circulation gas having the below-described composition was caused to flow through the quartz reaction tube at the below-described flow rate, the temperature of the reaction tube was elevated at the below-described temperature elevation rate by means of an electric furnace, and CO and CO2 concentrations were measured at the outlet of the reaction tube by means of an infrared analyzer. The temperature as measured at the inlet of the catalyst-containing reaction tube when CO2 concentration reached 30 ppm (i.e., electric furnace control temperature) was regarded as Tig (combustion initiation temperature).
- Gas composition: O2: 10%, N2: 90%
- Flow rate: 400 cc/min
- Temperature elevation rate: 10 degrees (° C.)/min
- Monoclinic zirconium oxide (ZrO2) particles or γ-alumina (Al2O3) particles were employed as a carrier. The powdery carrier was mixed with aqueous silver nitrate solution or nitric acid solution of (dinitrodiamine)Pt so that the amount of a catalyst component supported (as reduced to metallic silver or metallic platinum) on the basis of the mass of the carrier was adjusted as shown in Table 1. The resultant mixture was stirred for one hour. Thereafter, water was evaporated under heating, followed by drying at 120° C. The thus-dried product was fired at 750° C. for 20 hours, to thereby produce a particulate combustion catalyst. Table 1 shows the BET specific surface area and Tig of the particulate combustion catalyst.
-
TABLE 1 Catalyst com- Amount BET specific Carrier ponent supported surface area Tig Comparative ZrO2 Ag 0 mass % 25.6 m2/g 384° C. Example 1 Example 1 ZrO2 Ag 0.5 mass % 20.7 m2/g 300° C. Example 2 ZrO2 Ag 1 mass % 19.2 m2/g 251° C. Example 3 ZrO2 Ag 2 mass % 16.0 m2/g 245° C. Example 4 ZrO2 Ag 5 mass % 15.3 m2/g 256° C. Example 5 ZrO2 Ag 9 mass % 13.1 m2/g 258° C. Example 6 ZrO2 Ag 10 mass % 10.2 m2/g 264° C. Comparative Al2O3 Ag 0 mass % 147.8 m2/g 479° C. Example 2 Comparative Al2O3 Ag 1 mass % 146.9 m2/g 487° C. Example 3 Comparative Al2O3 Ag 2 mass % 146.4 m2/g 476° C. Example 4 Comparative Al2O3 Ag 5 mass % 136.8 m2/g 441° C. Example 5 Comparative Al2O3 Pt 0 mass % 147.8 m2/g 479° C. Example 6 Comparative Al2O3 Pt 1 mass % 142.8 m2/g 458° C. Example 7 Comparative Al2O3 Pt 2 mass % 151.2 m2/g 459° C. Example 8 Comparative Al2O3 Pt 5 mass % 147.8 m2/g 461° C. Example 9 - As is clear from data shown in Table 1 (Examples 1 to 6), when Ag (i.e., a catalyst component) was supported on a carrier formed of monoclinic zirconium oxide particles so that the amount of the catalyst component was adjusted to 0.5 to 10 mass % (as reduced to metallic Ag) on the basis of the mass of the carrier, the resultant catalyst exhibited a Tig of 300° C. or lower and had a BET specific surface area of 8 to 21 m2/g, and when the catalyst component was supported on the carrier so that the amount of the catalyst component was adjusted to 1 to 9 mass % (as reduced to metallic Ag) on the basis of the mass of the carrier, the resultant catalyst exhibited a Tig of 260° C. or lower and had a BET specific surface area of 11 to 20 m2/g. In contrast, as is clear from data obtained in Comparative Examples 2 to 9, when Al2O3 was employed as a carrier in place of ZrO2, or when Pt was employed as a catalyst component in place of Ag, the Tig of the resultant catalyst was not low.
- Monoclinic zirconium oxide (ZrO2) particles were employed as a carrier. The powdery carrier was mixed with an aqueous silver nitrate solution so that the amount of a catalyst component supported (as reduced to metallic silver) on the basis of the mass of the carrier was adjusted as shown in Table 2. The resultant mixture was stirred for one hour. Thereafter, water was evaporated under heating, followed by drying at 120° C. The thus-dried product was fired at 750° C. for 20 hours, to thereby produce a particulate combustion catalyst. Table 2 shows the BET specific surface area and Tig of the particulate combustion catalyst.
-
TABLE 2 Car- Catalyst Amount BET specific rier component supported surface area Tig Comparative ZrO2 Ag 0 mass % 10.0 m2/g 396° C. Example 10 Example 7 ZrO2 Ag 0.5 mass % 9.5 m2/g 300° C. Example 8 ZrO2 Ag 1 mass % 8.5 m2/g 268° C. Example 9 ZrO2 Ag 2 mass % 8.4 m2/g 269° C. Example 10 ZrO2 Ag 5 mass % 8.4 m2/g 274° C. Example 11 ZrO2 Ag 10 mass % 8.3 m2/g 269° C. - Monoclinic zirconium oxide particles were employed as a carrier. The powdery carrier was mixed with an aqueous silver nitrate solution so that the amount of a catalyst component supported (as reduced to metallic silver) was adjusted to 1 mass % on the basis of the mass of the carrier, and the resultant mixture was stirred for one hour. Thereafter, water was evaporated under heating, followed by drying at 120° C. The thus-dried product was fired at a temperature shown in Table 3 for 20 hours, to thereby produce a particulate combustion catalyst. Table 3 shows the BET specific surface area and Tig of the particulate combustion catalyst.
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TABLE 3 BET specific Firing temperature surface area Tig Example 12 600° C. 27.5 m2/g 277° C. Example 13 650° C. 23.2 m2/g 268° C. Example 14 700° C. 21.1 m2/g 271° C. Example 15 750° C. 19.2 m2/g 251° C. Example 16 800° C. 13.9 m2/g 259° C. Example 17 850° C. 11.9 m2/g 252° C. Example 18 900° C. 6.2 m2/g 275° C. - Monoclinic zirconium oxide particles were employed as a carrier. The powdery carrier was mixed with an aqueous silver nitrate solution so that the amount of a catalyst component supported (as reduced to metallic silver) was adjusted to 1 mass % on the basis of the mass of the carrier, and the resultant mixture was stirred for one hour. Thereafter, water was evaporated under heating, followed by drying at 120° C. The thus-dried product was fired at 750° C. for a period of time shown in Table 4, to thereby produce a particulate combustion catalyst. Table 4 shows the BET specific surface area and Tig of the particulate combustion catalyst.
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TABLE 4 BET specific Firing time surface area Tig Example 19 10 hours 19.1 m2/g 259° C. Example 20 15 hours 18.0 m2/g 256° C. Example 21 20 hours 19.2 m2/g 251° C. Example 22 25 hours 15.1 m2/g 254° C. Example 23 30 hours 14.7 m2/g 255° C. Example 24 50 hours 12.9 m2/g 258° C.
Claims (29)
1. A particulate combustion catalyst characterized by comprising a carrier formed of monoclinic zirconium oxide particles, and metallic Ag or Ag oxide, which serves as a catalyst component and is supported on the carrier, wherein the amount of the catalyst component is 0.5 to 10 mass %, as reduced to metallic Ag, on the basis of the mass of the carrier.
2. A particulate combustion catalyst according to claim 1 , which is produced through firing at 600 to 900° C. for 10 hours or longer.
3. A particulate combustion catalyst according to claim 1 , which has a BET specific surface area of 8 to 21 m2/g.
4. A particulate combustion catalyst according to claim 1 , which exhibits a combustion initiation temperature (Tig) of 300° C. or lower.
5. A particulate combustion catalyst characterized by comprising a carrier formed of monoclinic zirconium oxide particles, and metallic Ag or Ag oxide, which serves as a catalyst component and is supported on the carrier, wherein the amount of the catalyst component is 1 to 9 mass %, as reduced to metallic Ag, on the basis of the mass of the carrier, and the catalyst has a BET specific surface area of 11 to 20 m2/g.
6. A particulate combustion catalyst according to claim 5 , which exhibits a combustion initiation temperature (Tig) of 260° C. or lower.
7. A particulate combustion catalyst according to claim 1 , which is produced through firing at 730 to 870° C. for 10 hours or longer.
8. A particulate filter characterized by comprising a base coated with a particulate combustion catalyst as recited in claim 1 .
9. An exhaust gas cleaning apparatus characterized by comprising a particulate filter coated with a particulate combustion catalyst as recited in claim 1 .
10. A particulate combustion catalyst characterized by comprising a carrier formed of monoclinic zirconium oxide particles, and metallic Ag or Ag oxide, which serves as a catalyst component and is supported on the carrier, wherein the amount of the catalyst component is 0.5 to 10 mass %, as reduced to metallic Ag, on the basis of the mass of the carrier.
11. A particulate combustion catalyst according to claim 10 , which is produced through firing at 600 to 900° C. for 10 hours or longer.
12. A particulate combustion catalyst according to claim 10 , which has a BET specific surface area of 8 to 21 m2/g.
13. A particulate combustion catalyst according to claim 11 , which has a BET specific surface area of 8 to 21 m2/g.
14. A particulate combustion catalyst according to claim 10 , which exhibits a combustion initiation temperature (Tig) of 300° C. or lower.
15. A particulate combustion catalyst according to claim 13 , which exhibits a combustion initiation temperature (Tig) of 300° C. or lower.
16. A particulate combustion catalyst characterized by comprising a carrier formed of monoclinic zirconium oxide particles, and metallic Ag or Ag oxide, which serves as a catalyst component and is supported on the carrier, wherein the amount of the catalyst component is 1 to 9 mass %, as reduced to metallic Ag, on the basis of the mass of the carrier, and the catalyst has a BET specific surface area of 11 to 20 m2/g.
17. A particulate combustion catalyst according to claim 16 , which exhibits a combustion initiation temperature (Tig) of 260° C. or lower.
18. A particulate combustion catalyst according to claim 10 , which is produced through firing at 730 to 870° C. for 10 hours or longer.
19. A particulate combustion catalyst according to claim 11 , which is produced through firing at 730 to 870° C. for 10 hours or longer.
20. A particulate combustion catalyst according to claim 12 , which is produced through firing at 730 to 870° C. for 10 hours or longer.
21. A particulate combustion catalyst according to claim 15 , which is produced through firing at 730 to 870° C. for 10 hours or longer.
22. A particulate filter characterized by comprising a base coated with a particulate combustion catalyst as recited in claim 10 .
23. A particulate filter characterized by comprising a base coated with a particulate combustion catalyst as recited in claim 11 .
24. A particulate filter characterized by comprising a base coated with a particulate combustion catalyst as recited in claim 12 .
25. A particulate filter characterized by comprising a base coated with a particulate combustion catalyst as recited in claim 15 .
26. An exhaust gas cleaning apparatus characterized by comprising a particulate filter coated with a particulate combustion catalyst as recited in claim 10 .
27. An exhaust gas cleaning apparatus characterized by comprising a particulate filter coated with a particulate combustion catalyst as recited in claim 11 .
28. An exhaust gas cleaning apparatus characterized by comprising a particulate filter coated with a particulate combustion catalyst as recited in claim 12 .
29. An exhaust gas cleaning apparatus characterized by comprising a particulate filter coated with a particulate combustion catalyst as recited in claim 15 .
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Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4927799A (en) * | 1986-04-11 | 1990-05-22 | Toyota Jidosha Kabushiki Kaisha | Catalyst for the purification of exhaust gas |
US5540981A (en) * | 1994-05-31 | 1996-07-30 | Rohm And Haas Company | Inorganic-containing composites |
US5935529A (en) * | 1995-09-08 | 1999-08-10 | Kabushiki Kaisha Riken | Exhaust gas cleaner and method for cleaning exhaust gas |
US6034029A (en) * | 1996-12-20 | 2000-03-07 | Basf Aktiengesellschaft | Monoclinic zirconium dioxide having a large surface area |
US20050135980A1 (en) * | 2003-12-19 | 2005-06-23 | Park Paul W. | Silver doped catalysts for treatment of exhaust |
FR2905371A1 (en) * | 2006-08-31 | 2008-03-07 | Rhodia Recherches & Tech | HIGH REDUCIBILITY COMPOSITION BASED ON NANOMETRY CERIUM OXIDE ON A CARRIER, PROCESS FOR PREPARATION AND USE AS CATALYST |
Family Cites Families (11)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4902487A (en) | 1988-05-13 | 1990-02-20 | Johnson Matthey, Inc. | Treatment of diesel exhaust gases |
JPH0975739A (en) * | 1995-07-11 | 1997-03-25 | Riken Corp | Waste gas purification material and method for purifying waste gas |
JPH0985053A (en) * | 1995-09-21 | 1997-03-31 | Riken Corp | Exhaust gas purifying material and exhaust gas purifying method |
JP3421958B2 (en) * | 1995-09-22 | 2003-06-30 | 日野自動車株式会社 | Exhaust gas purification device for turbocharged engine |
JPH1047035A (en) | 1996-08-08 | 1998-02-17 | Sumitomo Electric Ind Ltd | Particulate trap for diesel engine |
JPH115035A (en) * | 1997-04-23 | 1999-01-12 | Riken Corp | Waste gas purification material and method for purifying waste gas |
US6677063B2 (en) * | 2000-08-31 | 2004-01-13 | Ppg Industries Ohio, Inc. | Methods of obtaining photoactive coatings and/or anatase crystalline phase of titanium oxides and articles made thereby |
JP3528839B2 (en) | 2002-05-15 | 2004-05-24 | トヨタ自動車株式会社 | Particulate oxidizer and oxidation catalyst |
JP2004058013A (en) | 2002-07-31 | 2004-02-26 | Nissan Motor Co Ltd | Purification catalyst for exhaust gas |
EP1637225A4 (en) * | 2003-06-09 | 2007-12-19 | Nippon Sheet Glass Co Ltd | Photocatalyst member |
EP1932590B1 (en) * | 2005-10-06 | 2013-03-27 | Mitsui Mining and Smelting Co., Ltd. | Particulate combustion catalyst, particulate filter, and exhaust gas clean-up system |
-
2008
- 2008-10-23 US US12/994,504 patent/US20110076202A1/en not_active Abandoned
- 2008-10-23 EP EP08874480.0A patent/EP2289619B1/en active Active
- 2008-10-23 CN CN201410440863.0A patent/CN104279025A/en active Pending
- 2008-10-23 WO PCT/JP2008/069243 patent/WO2009144847A1/en active Application Filing
- 2008-10-23 CN CN200880129514XA patent/CN102046287A/en active Pending
- 2008-10-23 JP JP2010514331A patent/JP5328783B2/en active Active
-
2013
- 2013-09-03 US US14/016,795 patent/US9393522B2/en active Active
Patent Citations (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4927799A (en) * | 1986-04-11 | 1990-05-22 | Toyota Jidosha Kabushiki Kaisha | Catalyst for the purification of exhaust gas |
US5540981A (en) * | 1994-05-31 | 1996-07-30 | Rohm And Haas Company | Inorganic-containing composites |
US5935529A (en) * | 1995-09-08 | 1999-08-10 | Kabushiki Kaisha Riken | Exhaust gas cleaner and method for cleaning exhaust gas |
US6034029A (en) * | 1996-12-20 | 2000-03-07 | Basf Aktiengesellschaft | Monoclinic zirconium dioxide having a large surface area |
US20050135980A1 (en) * | 2003-12-19 | 2005-06-23 | Park Paul W. | Silver doped catalysts for treatment of exhaust |
FR2905371A1 (en) * | 2006-08-31 | 2008-03-07 | Rhodia Recherches & Tech | HIGH REDUCIBILITY COMPOSITION BASED ON NANOMETRY CERIUM OXIDE ON A CARRIER, PROCESS FOR PREPARATION AND USE AS CATALYST |
US20100111789A1 (en) * | 2006-08-31 | 2010-05-06 | Franck Fajardie | Catalyst/catalyst support compositions having high reducibility and comprising a nanometric cerium oxide deposited onto a support substrate |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2015077578A (en) * | 2013-10-18 | 2015-04-23 | 株式会社キャタラー | Diesel particulate filter catalyst |
Also Published As
Publication number | Publication date |
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WO2009144847A1 (en) | 2009-12-03 |
EP2289619A1 (en) | 2011-03-02 |
US20140004026A1 (en) | 2014-01-02 |
JPWO2009144847A1 (en) | 2011-10-06 |
CN104279025A (en) | 2015-01-14 |
EP2289619B1 (en) | 2019-04-24 |
EP2289619A4 (en) | 2011-12-14 |
US9393522B2 (en) | 2016-07-19 |
JP5328783B2 (en) | 2013-10-30 |
CN102046287A (en) | 2011-05-04 |
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