GB2236493A - Exhaust gas purification catalyst - Google Patents

Exhaust gas purification catalyst Download PDF

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Publication number
GB2236493A
GB2236493A GB9021493A GB9021493A GB2236493A GB 2236493 A GB2236493 A GB 2236493A GB 9021493 A GB9021493 A GB 9021493A GB 9021493 A GB9021493 A GB 9021493A GB 2236493 A GB2236493 A GB 2236493A
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United Kingdom
Prior art keywords
exhaust gas
catalyst
weight
gas cleaner
filter
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Granted
Application number
GB9021493A
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GB2236493B (en
GB9021493D0 (en
Inventor
Gyo Muramatsu
Satoshi Sumiya
Kiyohide Yoshida
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Riken Corp
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Riken Corp
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Publication of GB2236493B publication Critical patent/GB2236493B/en
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Classifications

    • 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
    • B01J23/70—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper
    • B01J23/76—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper combined with metals, oxides or hydroxides provided for in groups B01J23/02 - B01J23/36
    • B01J23/78—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper combined with metals, oxides or hydroxides provided for in groups B01J23/02 - B01J23/36 with alkali- or alkaline earth metals
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
    • B01J23/70—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper
    • B01J23/76—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper combined with metals, oxides or hydroxides provided for in groups B01J23/02 - B01J23/36
    • B01J23/83—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper combined with metals, oxides or hydroxides provided for in groups B01J23/02 - B01J23/36 with rare earths or actinides
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
    • B01J23/70—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper
    • B01J23/89—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper combined with noble metals
    • B01J23/8926—Copper and noble metals
    • 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
    • F01N3/2882—Catalytic reactors combined or associated with other devices, e.g. exhaust silencers or other exhaust purification devices
    • 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
    • F01N2250/00—Combinations of different methods of purification
    • F01N2250/02—Combinations of different methods of purification filtering and catalytic conversion
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2510/00—Surface coverings
    • F01N2510/06—Surface coverings for exhaust purification, e.g. catalytic reaction
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/10—Internal combustion engine [ICE] based vehicles
    • Y02T10/12—Improving ICE efficiencies

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  • 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)
  • Environmental & Geological Engineering (AREA)
  • Biomedical Technology (AREA)
  • Analytical Chemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Oil, Petroleum & Natural Gas (AREA)
  • Toxicology (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Exhaust Gas Treatment By Means Of Catalyst (AREA)
  • Catalysts (AREA)
  • Processes For Solid Components From Exhaust (AREA)
  • Filtering Materials (AREA)

Abstract

An exhaust gas is cleaned using a catalyst supported by a heat-resistant filter such as a cordierite honeycomb. The catalyst consists esssentially of Cs, Cu and at least one of Ce and La for oxidizing fine carbonaceous particles in the exhaust gas and simultaneously reducing nitrogen oxides with the fine carbonaceous particles as a reducing agent. Silver is optionally present.

Description

EXHAUST GAS CLEANER The present invention relates to an exhaust gas
cleaner and a method of cleaning an exhaust gas by using such an exhaust gas cleaner, and more particularly to an exhaust gas cleaner comprising a filter carrying a catalyst and a method of cleaning an exhaust gas from diesel engines, etc. by using this exhaust gas cleaner.
Recently, nitrogen oxides and fine carbonaceous particles (mainly composed of fine, solid carbon particles, and fine, liquid or solid high-molecular weight hydrocarbon particles) contained mainly in exhaust gases of diesel engines have been causing environmental problems.
Since these fine carbonaccous particles have an average particle size of 0.1-1 gm, the fine carbonaceous particles are likely to float in the air and be inhaled by breathing. In addition, a recent clinical test has shown that the fine carbonaceous particles contain carcinogens.
The removal of these fine particles is generally carried out by one of the following two methods: One method comprises passing the exhaust gas through a heat-resistant filter to trap the fine particles, and burnina the trapped fine particles by a burner, an electric heater, etc. when pressure loss has increased to a certain level, thereby regenerating the filter. such a filter may be a metal wire mesh, a ceramic foam, a monolithic ceramic honeycomb, etc. Another method comprises using a heat-resistant filter carrying a catalytic material for performing both filtration and burning actions, thereby reducing the frequency of burning fine particles and regenerating the filter. By increasing the activity of the catalyst, the regeneration of the filter can be omitted.
Attempts have been made in these methods to lower the ignition temperature of fine particles by increasing the percentages of combustible components in the exhaust gas, or by adding a carbonaceous oxidation accelerator to a fuel.
In the former method, as the removal effect of fine particles increases, the pressure loss takes place more quickly, and so the regeneration of the filter should be conducted more frequently. In addition, the regeneration needs to have high reliability, meaning that this method is economically disadvantageous.
On the other hand, the latter method would be considered to be an excellent method if there is a catalyst capable of maintaining its activity at exhaust gas conditions of diesel engines (gas composition and temperature). However, the exhaust gas temperatures of diesel engines are relatively lower than those of gasoline engines. In addition, since a gas oil is used as a fuel in diesel engines, the exhaust gases contain a large amount Of S02. Nevertheless, there has been no established method of well igniting and burning fine carbonaceous particles accumulated under these exhaust gas conditions without causing secondary pollution.
0 For instance, when base metal catalysts are supported on filters, the fine carbonaceous particles are ignited at as high a temperature as 3STC or higher. However, for most of the usual operations of diesel engines, etc., the exhaust gas temperature is lower than the above temperature, failing to cause a combustion reaction. As a result, fine particles are trapped by a catalyst-carrying filter and then burned when the temperature has increased to a certain level, thereby regenerating the filter. In this case, the pressure loss increases quickly until the filter reaches a certain temperature, necessitating the frequent burning and regeneration by a burner, an electric heater, etc. This is a practical disadvantage. When a catalyst containing precious metals is used, the fine particles are likely to be burned at a lower temperature, reducing the rate of increase of the pressure loss. However, the oxidation Of S02 in the exhaust gas takes place simultaneously. As a result, extremely harmful S03 and sulfuric acid mist are generated, causing secondary air pollution.
As mentioned above, there has been no known method of efficiently removing the fine carbonaceous particles from the exhaust gas discharged from diesel engines, etc. In addition, it is extremely difficult to remove nitrogen oxides from the exhaust gas whose oxygen concentration varies in a wide range of 2-20%.
Japanese Patent Laid-Open No. 63-242346 discloses a method of removina fine carbonaceous particles and nitroaen oxides from exhaust gas by using a heat-resistant filter carrying a catalyst comprising alkali metals and transition metals. However, even by this method, the removal ratio of nitrogen oxides at an exhaust gas temperature of about 30TC is less than 20%. Accordingly, the development of better catalysts has been desired.
Accordingly, an object of the present invention is to provide an exhaust gas cleaner capable of not only effectively burning fine carbonaceous particles contained in the exhaust gas having a relatively large oxygen concentration variation at a relatively low temperature such as those of diesel engines, but also effectively removing nitrogen oxides by reaction with the fine carbonaceous particles.
Another object of the present invention is to provide a method of cleaning an exhaust gas by using such an exhaust gas cleaner.
In view of the above objectives, the inventors have investigated a reaction between fine carbonaceous particles, oxygen and nitrogen oxides in the presence of a catalyst. As a result, it has been found that a combination of particular elements in group IA (alkali metals), the group IB (transition metals), and the rare earth metal group is effective as a catalyst for cleaning the exhaust gas, when supported by a heat-resistant filter. The present invention is based on this finding.
Thus, the exhaust gas cleaner according to the present invention comprises a heat-resistant filter and a catalyst supported by the filter, the catalyst comprising Cs, Cu and at least one of Ce and La.
The method of cleaning an exhaust gas according to the present invention comprises using a catalyst supported by a heat resistant filter, the catalyst comprising Cs, Cu and at least one of Ce and La for oxidizing fine carbonaceous particles in the 0 exhaust gas and simultaneously reducing nitrogen oxides with the fine carbonaceous particles as a reducing agent.
The exhaust gas cleaner according to the present invention comprises a heat-resistant filter and a catalyst supported thereby. The heat-resistant filter used in the present invention is disposed in an exhaust gas passage of a diesel engine.
The catalyst for removing nitrogen oxides together with fine carbonaceous particles preferably consists of Cs, Cu and at least one of Ce and La. However, this catalyst may further contain Ag.
Since the fine carbonaceous particles are brought into contact with catalyst elements and oxygen on the filter, the ignition temperature of the fine carbonaceous particles decreases so that they are burned (oxidized) at 30WC or lower. Simultaneously the fine carbonaceous particles serve as a reducing agent to reduce nitrogen oxides. Thus, by using a catalyst consisting essentially of Cs, Cu and at least one of Ce and La, the fine carbonaceous particles are activated by oxygen contained in the exhaust gas at 30WC or lower, so that they can react with nitrogen oxides. As a result, nitrogen oxides are reduced to N2, and simultaneously the fine carbonaceous particles are oxidized to C02. Accordingly, the cleaning of the exhaust gas can be achieved at a temperature of 30WC or lower.
The heat-resistant filter is required to have necessary fine carbonaceous particle -trapping capacity while causing pressure drop within the permitted range. It is thus preferably constituted by ceramic fibers, a ceramic foam, a ceramic monolith, etc. usually used as a catalyst carrier, such as alumina, silica, titania, zirconia, alumina- titania, silica-titania, silica-zirconia, titania-zirconia, mullite, cordierite, etc.
The impregnation of the heat-resistant filter with the fine carbonaceous particle -removing catalyst may be conducted by a known method in which the heat-resistant filter is immersed in solutions of carbonates, nitrates, acetates, and hydroxides of such catalyst elements.
To increase the catalyst-supporting area of the filter, it is desirable that the heat-resistant filter supports the catalysts via a porous carrier layer having a large surface area such as alumina powder, silica powder, titania powder, etc. When the carrier is used, the catalyst can be supported by the carrier by an impregnation method, a precipitation method, a sol-gel method, etc. The impregnation method is as mentioned above. The precipitation method comprises the coprecipitation of catalyst metals and ceramic carrier materials by mixing aqueous solutions of salts of both materials. The sol-gel method comprises mixing an alcohol solution of a organometallic salt of carrier ceramics such as titanium alkoxide with an aqueous solution of catalyst elements and acids such as hydrochloric acid, nitric acid, etc.
The amounts of the catalyst elements may generally be expressed in terms of the amount of the carrier. specifically, per 100 parts by weight of the carrier, Cs is 0.5 parts by weight or more, preferably 0.5-10 parts by weight, Cu is 2 parts by weight or more, preferably 2-20 parts by weight, and at least one of Cc and La is 0.5 parts by weight or more, preferably 0.5-10 parts by weight. When the amounts of these elements are smaller than the above lower limits, sufficient effects of removing both nitrogen oxides and fine 0 carbonaceous particles cannot be achieved. The more preferred amounts are 1-5 parts by weight (Cs), 5-15 parts by weight (Cu), and 1-5 parts by weight (at least one of Cc and La).
When the catalyst contains Ag, the amount of Ag is 0.01 parts by weight or more per 100 parts by weight of the carrier, preferably 0.01-5 parts by weight. When it is less than 0.01 parts by weight, sufficient effect of lowering the ignition temperature of fine carbonaceous particles and increasing the NOX removal ratio cannot be achieved. The more preferred amount of Ag is 0.05-2 parts by weight or more.
Incidentally, the amount of the carrier relative to the heat resistant filter may vary depending upon the type of the filter, but it is generally 2-15 parts by weight per 100 parts by weight of the filter.
The present invention will be explained in further detail by the following Examples.
Examples 1-4
A commercially available ceramic honeycomb made of cordierite hving a volume of 2 1, a density of 0.37 g/mI and a porosity of 86.0% (mainly composed of magnesia, alumina and silica) was coated with titania powder (average particle size: 0.04 ptm) in an amount of 10 weight % based on the ceramic honeycomb by an impregnation method, and the resulting titania layer was impregnated with 2.5 weight % of Cs by using CSN03, 10 weight % of Cu by using C11C12, and 2.5 weight % of Ce by using Ce(N03)3. The amount of catalyst element is based on the carrier. This catalyst-carrying ceramic filter was dried at 15WC or lower and then burned at 7000C for 3 hours. The resulting exhaust gas cleaner is identified as:
-)o (Cs/Cu/Ce: Example 1) In the same manner as in Example 1, a ceramic honeycomb filter was impregnated with 2.5 weight % of Cs, 10 weight % of Cu, and 2.5 weight % of La by using LaC13 (Example 2).
Also, the exhaust gas cleaner of Example 1 was further impregnated with 0.5 weight % of Ag by using AgN03 (Example 3).
Similarly, the exhaust gas cleaner of Example 2 was further impregnated with 0.5 weight % of Ag (Example 4).
(Cs/Cu/La: Example 2), (Cs/CulCe/Ag: Example 3), and (Cs/Cu/La/Ag: Example 4).
Each of the exhaust gas cleaners in Examples 1-4 was evaluated with respect to the ignition temperature of fine carbonaceous particles (expressed by temperature at which pressure drop decreases) and the removal ratio of NO,, (conversion ratio of NO.
to N2) by using a single-cylinder engine having a displacement of 510 cc. The engine was operated at 1500 rpm under a load of 90%. NOx concentration was about 480 ppm and oxygen concentration was 5% in 0 the exhaust gas. The results are shown in Table 1.
Comparative Example 1 For comparison, an exhaust gas cleaner was produced from a cordierite honeycomb filter without a catalyst and measured with respect to the ignition temperature and the NOx removal ratio in the same manner as in Examples. The results are shown in Table 1.
Table 1
NOX Removal Ratio at 30WC 0 No. - Ignition Temp. PC) (%) Example 1 280 21 Example 2 275 20 Example 3 272 27 Example 4 267 25 Comparative Example 1 600 - The exhaust gas cleaners of Examples 1-4 showed the ignition temperatures of 267'C-28TC and a high NOx removal ratio of 20% or more. On the other hand, NOX was not removed by the exhaust gas cleaner of Comparative Example 1.
As described above, by using the exhaust gas cleaner according to the present invention, fine carbonaceous particles and nitrogen oxides can be removed efficiently from the exhaust gas even at a relatively low temperature.

Claims (9)

-10CLAIMS:
1. An exhaust gas cleaner comprising a heat-resistant filter and a catalyst supported by said filter, said catalyst comprising Cs, Cu and at least one of Ce and La.
2. An exhaust gas cleaner as claimed in claim 1 wherein said catalyst consists essentially of Cs, Cu and at least one of Ce and La.
3. An exhaust gas cleaner as claimed in claim 1, wherein said catalyst further contains Ag.
4. An exhaust gas cleaner as claimed in any one of claims 1-3 in which the heat-resistant filter supports the catalysts via a porous carrier layer.
5. An exhaust gas cleaner as claimed in claim 4, wherein said carrier comprises 0.5 parts by weight or more of Cs, 2 parts by weight or more of Cu and 0.5 parts by weight or more of Ce or La, based on the weight of the carrier.
6. An exhaust gas cleaner as claimed in claim 1 substantially as herein described with reference to any of examples 1-4.
7. A method of cleaning an exhaust gas, which method comprises passing said exhaust gas through a catalyst supported by a heat-resistant filter, said catalyst comprising Cs, Cu and at least one of Ce and La, so as to oxidize fine carbonaceous particles which are present in said exhaust gas and simultaneously reduce nitrogen oxides in the presence of said fine carbonaceous particles as a reducing agent.
8. A method as claimed in claim 7 wherein said catalyst further contains Ag.
9. A method as claimed in claim 7 substantially as herein described with reference to any of examples 1 to 4.
Published 1991 at The Patent Office. State House, 66/71 High Holborn. London WC1 R 47P. Further copies may be obtained from Sales Branch. Unit 6. Nint: Mile Point. Cwmfelinfach, Cross Keys. Newport. NPI 7HZ. Printed by Multiplex techniques lid, St Mary Cray. Kent-
GB9021493A 1989-10-03 1990-10-03 Exhaust gas cleaner Expired - Fee Related GB2236493B (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP25856789A JP2863567B2 (en) 1989-10-03 1989-10-03 Exhaust gas purifying material and exhaust gas purifying method

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GB9021493D0 GB9021493D0 (en) 1990-11-14
GB2236493A true GB2236493A (en) 1991-04-10
GB2236493B GB2236493B (en) 1993-10-13

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Cited By (19)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2248194A (en) * 1990-09-25 1992-04-01 Riken Kk Catalyst for cleaning exhaust gases
FR2714717A1 (en) * 1993-12-31 1995-07-07 Rhone Poulenc Chimie Reduction of carbonaceous particulate emissions in vehicle exhausts
US5462907A (en) * 1991-11-26 1995-10-31 Engelhard Corporation Ceria-alumina oxidation catalyst
FR2720405A1 (en) * 1994-05-25 1995-12-01 Rhone Poulenc Chimie Reduction of carbonaceous particulate emissions in vehicle exhausts
US5491120A (en) * 1991-11-26 1996-02-13 Engelhard Corporation Oxidation catalyst with bulk ceria, a second bulk metal oxide, and platinum
EP0712660A1 (en) * 1993-07-29 1996-05-22 Hongxing Zhou Bifunctional catalyst containing multimetal oxides
EP0714693A1 (en) * 1994-11-28 1996-06-05 Kabushiki Kaisha Riken Exhaust gas cleaner and method for cleaning exhaust gas
US5580535A (en) * 1994-07-07 1996-12-03 Engelhard Corporation System and method for abatement of food cooking fumes
EP0710499A3 (en) * 1994-11-04 1997-05-21 Agency Ind Science Techn Exhaust gas cleaner and method for cleaning exhaust gas
DE19623425A1 (en) * 1996-06-12 1997-12-18 Dlr Deutsche Forschungsanstalt Reaction bonded mullite-based ceramic article
GB2355943A (en) * 1999-11-03 2001-05-09 Johnson Matthey Plc Control of diesel particulate pollution
GB2375058A (en) * 2001-03-29 2002-11-06 Daimler Chrysler Ag Exhaust gas particle filter
EP1378288A3 (en) * 2002-04-18 2004-01-14 Ford Global Technologies, LLC, A subsidary of Ford Motor Company Platinum-group-metal free catalytic washcoats for particulate exhaust gas filter applications
US6790807B2 (en) 2001-09-13 2004-09-14 Rothmans, Benson & Hedges Inc. Zirconium/metal oxide fibers
EP1990082A1 (en) 2007-05-11 2008-11-12 Ford Global Technologies, LLC PGM-free DPF catalyst for soot oxidation
US7485271B2 (en) 2003-08-09 2009-02-03 Johnson Matthey Public Limited Company Catalyst structure for treating NOx containing exhaust gas from a lean burn engine
US8267096B2 (en) 2000-09-18 2012-09-18 Rothmans, Benson & Hedges, Inc. Low sidestream smoke cigarette with combustible paper
US8387367B2 (en) 2005-11-14 2013-03-05 Johnson Matthey Public Limited Company Reducing coking over Ag/Al2O3 HC-SCR catalyst
US8518333B2 (en) 2005-07-21 2013-08-27 Ibiden Co., Ltd. Honeycomb structured body and exhaust gas purifying device

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US6248684B1 (en) 1992-11-19 2001-06-19 Englehard Corporation Zeolite-containing oxidation catalyst and method of use
DE4336132A1 (en) * 1993-10-22 1994-12-08 Siemens Ag Process for purifying an exhaust gas
IT1307693B1 (en) 1999-05-14 2001-11-14 Fiat Ricerche PROCEDURE FOR THE PRODUCTION OF A PARTICULATE FILTER FOR MOTORIDIESEL, USING A HIGH PERFORMANCE CERAMIC FOAM
JP2007253144A (en) * 2005-07-21 2007-10-04 Ibiden Co Ltd Honeycomb structured body and exhaust gas purifying device
JP2007098274A (en) * 2005-10-04 2007-04-19 Ibiden Co Ltd Porous honeycomb structure and apparatus for purifying exhaust gas using the same
CN102909023A (en) * 2012-09-14 2013-02-06 广州市卫斯理日化实业有限公司 Automobile exhaust catalyst and preparation method thereof

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GB1443234A (en) * 1972-08-25 1976-07-21 Hitachi Ltd Method of treating a gas containing one or more nitrogen oxides
GB1473951A (en) * 1973-05-29 1977-05-18 Western Electric Co Improvements in or relating to catalysts for exhaust gas treatment
GB1492945A (en) * 1974-09-20 1977-11-23 British Petroleum Co Process for producing vinyl chloride
EP0320243A1 (en) * 1987-12-11 1989-06-14 Johnson Matthey Public Limited Company Catalysts

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Publication number Priority date Publication date Assignee Title
GB1443234A (en) * 1972-08-25 1976-07-21 Hitachi Ltd Method of treating a gas containing one or more nitrogen oxides
GB1473951A (en) * 1973-05-29 1977-05-18 Western Electric Co Improvements in or relating to catalysts for exhaust gas treatment
GB1492945A (en) * 1974-09-20 1977-11-23 British Petroleum Co Process for producing vinyl chloride
EP0320243A1 (en) * 1987-12-11 1989-06-14 Johnson Matthey Public Limited Company Catalysts

Cited By (35)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2248194A (en) * 1990-09-25 1992-04-01 Riken Kk Catalyst for cleaning exhaust gases
US5208202A (en) * 1990-09-25 1993-05-04 Kabushiki Kaisha Riken Exhaust gas cleaner and method of cleaning exhaust gas catalyst for cleaning exhaust gas
GB2248194B (en) * 1990-09-25 1994-11-09 Riken Kk Catalyst for cleaning exhaust gas
US5384110A (en) * 1990-09-25 1995-01-24 Kabushiki Kaisha Riken Exhaust gas cleaner and method of cleaning exhaust gas
US6255249B1 (en) 1991-11-26 2001-07-03 Engelhard Corporation Oxidation catalyst and method of use
US5462907A (en) * 1991-11-26 1995-10-31 Engelhard Corporation Ceria-alumina oxidation catalyst
US5491120A (en) * 1991-11-26 1996-02-13 Engelhard Corporation Oxidation catalyst with bulk ceria, a second bulk metal oxide, and platinum
US6153160A (en) * 1991-11-26 2000-11-28 Engelhard Corporation Catalytic oxidation method
US5627124A (en) * 1991-11-26 1997-05-06 Engelhard Corporation Ceria-alumina oxidation catalyst
EP0712660A1 (en) * 1993-07-29 1996-05-22 Hongxing Zhou Bifunctional catalyst containing multimetal oxides
EP0712660A4 (en) * 1993-07-29 1997-02-04 Hongxing Zhou Bifunctional catalyst containing multimetal oxides
FR2714717A1 (en) * 1993-12-31 1995-07-07 Rhone Poulenc Chimie Reduction of carbonaceous particulate emissions in vehicle exhausts
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GB2236493B (en) 1993-10-13
DE4031385A1 (en) 1991-04-11
JPH03118811A (en) 1991-05-21
GB9021493D0 (en) 1990-11-14
JP2863567B2 (en) 1999-03-03

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