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
  • B01J23/40—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals of the platinum group metals
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D46/00—Filters or filtering processes specially modified for separating dispersed particles from gases or vapours
  • B01D46/24—Particle separators, e.g. dust precipitators, using rigid hollow filter bodies
  • B01D46/2403—Particle separators, e.g. dust precipitators, using rigid hollow filter bodies characterised by the physical shape or structure of the filtering element
  • B01D46/2418—Honeycomb filters
• • 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
  • B01J23/38—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
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
  • B01J37/02—Impregnation, coating or precipitation
  • B01J37/024—Multiple impregnation or coating
  • B01J37/0242—Coating followed by impregnation
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
  • B01J37/02—Impregnation, coating or precipitation
  • B01J37/024—Multiple impregnation or coating
  • B01J37/0248—Coatings comprising impregnated particles
• • 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
• • 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
  • F01N3/022—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 characterised by specially adapted filtering structure, e.g. honeycomb, mesh or fibrous
  • F01N3/0222—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 characterised by specially adapted filtering structure, e.g. honeycomb, mesh or fibrous the structure being monolithic, e.g. honeycombs
• • 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
• • 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
  • F01N3/0807—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by using absorbents or adsorbents
  • F01N3/0814—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by using absorbents or adsorbents combined with catalytic converters, e.g. NOx absorption/storage reduction catalysts
• • 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
  • F01N3/0807—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by using absorbents or adsorbents
  • F01N3/0828—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by using absorbents or adsorbents characterised by the absorbed or adsorbed substances
  • F01N3/0835—Hydrocarbons
• • 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
  • F01N3/0807—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by using absorbents or adsorbents
  • F01N3/0828—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by using absorbents or adsorbents characterised by the absorbed or adsorbed substances
  • F01N3/0842—Nitrogen oxides
• • 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
  • F01N3/101—Three-way catalysts
• • 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
  • F01N3/103—Oxidation catalysts for HC and CO only
• • 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
  • F01N3/18—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 methods of operation; Control
  • F01N3/20—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 methods of operation; Control specially adapted for catalytic conversion
  • F01N3/206—Adding periodically or continuously substances to exhaust gases for promoting purification, e.g. catalytic material in liquid form, NOx reducing agents
  • F01N3/2066—Selective catalytic reduction [SCR]
• • 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
  • B01D2255/1021—Platinum
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2255/00—Catalysts
  • B01D2255/10—Noble metals or compounds thereof
  • B01D2255/102—Platinum group metals
  • B01D2255/1023—Palladium
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2255/00—Catalysts
  • B01D2255/10—Noble metals or compounds thereof
  • B01D2255/102—Platinum group metals
  • B01D2255/1025—Rhodium
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2255/00—Catalysts
  • B01D2255/90—Physical characteristics of catalysts
  • B01D2255/903—Multi-zoned catalysts
  • B01D2255/9035—Three zones
• • 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
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2255/00—Catalysts
  • B01D2255/90—Physical characteristics of catalysts
  • B01D2255/91—NOx-storage component incorporated in the catalyst
• • 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
  • B01D2255/9205—Porosity
• • 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
• • 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
  • F01N2370/00—Selection of materials for exhaust purification
  • F01N2370/02—Selection of materials for exhaust purification used in catalytic reactors
• • 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
  • F01N2510/068—Surface coverings for exhaust purification, e.g. catalytic reaction characterised by the distribution of the catalytic coatings
  • F01N2510/0682—Surface coverings for exhaust purification, e.g. catalytic reaction characterised by the distribution of the catalytic coatings having a discontinuous, uneven or partially overlapping coating of catalytic material, e.g. higher amount of material upstream than downstream or vice versa
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
  • Y02T10/00—Road transport of goods or passengers
  • Y02T10/10—Internal combustion engine [ICE] based vehicles
  • Y02T10/12—Improving ICE efficiencies

Definitions

• the present invention relates to a catalyzed particulate filter, in particular a catalyzed particulate filter for use in an emission treatment system of an internal combustion engine.
• a catalyzed particulate filter for use in an emission treatment system of an internal combustion engine.
• catalyzed particulate filters for use in an emission treatment system of an internal combustion engine.
• emission treatment systems with catalyzed particulate filters provide for manufacturing catalyzed particulate filters, and methods for controlling emissions in exhaust gas from internal combustion engines with catalyzed particulate filters.
• Certain internal combustion engines such as lean-bum engines, diesel engines, natural gas engines, power plants, incinerators, or gasoline engines, tend to produce an exhaust gas with a considerable amount of particulate matter (PM).
• PM particulate matter
• Catalysts containing platinum group metals are accordingly located in the exhaust gas line of internal combustion engines. Such catalysts promote the oxidation by oxygen in the exhaust gas stream of unburned hydrocarbons and carbon monoxide as well as the reduction of nitrogen oxides to nitrogen.
• the catalyst is formed by coating the PGMs containing slurry on a substrate uniformly. In another technique, the platinum group metals are coated on the substrate in a zoned manner.
• China 6 World Harmonized Light-duty Vehicle Test Cycle
• the present invention relates to a catalyzed particulate filter, in particular a catalyzed particulate filter for use in an emission treatment system of an internal combustion engine.
• aspects include catalyzed particulate filters for exhaust gas treatment from internal combustion engines comprising a particulate filter, and a zoned catalytic layer
• SCR selective catalytic reduction
• TWO three way conversion
• DOC diesel oxidation catalyst
• AMOx ammonia oxidation
• NOx trap a NOx absorber catalyst
• hydrocarbon trap catalyst a selective catalytic reduction (SCR) catalyst
• SCR selective catalytic reduction
• TWO three way conversion
• DOC diesel oxidation catalyst
• AMOx ammonia oxidation
• NOx trap a NOx absorber catalyst
• hydrocarbon trap catalyst a hydrocarbon trap catalyst
• FIG. 1 (a) and (b) show an exemplary wall-flow filter
• FIG. 2(a), (b), (c), (d), (e), (f) and (g) show PGM distribution layouts for Examples 1 to 7;
• FIG. 3(a) and (b) show PGM distribution layouts for Examples 9 and 10;
• FIG. 4(a) and (b) show PGM distribution layouts for Examples 12 and 13;
• FIG. 5 shows a plot of gas emission results of catalyzed particulate filters according to embodiments of the present invention (Examples 2 to 7) and a prior art particulate filter (Example 1), tested under WLTC cycle;
• FIG. 6 shows a plot of gas emission results of catalyzed particulate filters according to embodiments of the present invention (Example 10) and a prior art particulate filter (Example 9), tested under WLTC cycle;
• FIG. 7 shows a plot of gas emission results of catalyzed particulate filters according to embodiments of the present invention (Example 13) and a prior art particulate filter (Example 12), tested under WLTC cycle.
• a catalyzed particulate filter for exhaust gas treatment from an internal combustion engine comprising:
• a particulate filter comprising a porous substrate having a total substrate length (L) an inlet surface, an outlet surface, an inlet axial end, an outlet axial end;
• a catalytic layer comprising a support material, and at least one platinum group metal (PGM) selected from platinum, palladium and rhodium; the catalytic layer being coated onto the inlet side, the outlet side, or both sides of the particulate filter; wherein the catalytic layer comprises a first zone, a second zone, and a third zone; the first zone begins at the inlet axial end and has a first length (L1) extending for 10- 45% of the total substrate length (L); the third zone begins at the outlet axial end and has a third length (L3) extending for 10-45% of the total substrate length (L); the second zone begins at the axial end of first zone, ends at the axial beginning of the third zone; and wherein the content of PGM in the first zone is higher than the content of PGM in the second zone, and the content of PGM in the third zone is higher than the content of PGM in the second zone, calculated as the weight of platinum group metal per zone volume.
• PGM platinum group metal
• the particulate filter is typically formed of a porous substrate.
• the porous substrate may comprise a ceramic material such as, for example, cordierite, silicon carbide, silicon nitride, zirconia, mullite, spodumene, alumina-silica- magnesia, zirconium silicate, and/or aluminium titanate, typically cordierite or silicon carbide.
• the porous substrate may be a porous substrate of the type typically used in emission treatment systems of internal combustion engines.
• the internal combustion engine may be a lean-burn engine, a diesel engine, a natural gas engine, a power plant, an incinerator, or a gasoline engine.
• the porous substrate may exhibit a conventional honey-comb structure.
• the filter may take the form of a conventional " flow-through filter”.
• the filter may take the form of a conventional "wall flow filter” (WFF).
• WFF wall flow filter
• the particulate filter is preferably a wall-flow filter.
• a wall-flow filter Referring to FIG. 1 (a) and FIG. 1 (b), an exemplary wall-flow filter is provided.
• Wall-flow filters work by forcing a flow of exhaust gases (13) (including particulate matter) to pass through walls formed of a porous material.
• a wall flow filter typically has a first axial end and a second axial end defining a longitudinal direction therebetween. In use, one of the first axial end and the second axial end will be the inlet axial end for exhaust gases (13) and the other will be the outlet axial end for the treated exhaust gases (14).
• a conventional wall flow filter has first and second pluralities of channels extending in the longitudinal direction. The first plurality of channels (11 ) is open at the inlet axial end (01 ) and closed at the outlet axial end (02). The second plurality of channels (12) is open at the outlet axial end (02) and closed at the inlet axial end (01 ). The channels are preferably parallel to each other to provide a constant wall thickness between the channels.
• the channels are closed with the introduction of a sealant material into the open end of a channel.
• the number of channels in the first plurality is equal to the number of channels in the second plurality, and each plurality is evenly distributed throughout the monolith.
• the wall flow filter has from 100 to 500 channels per square inch, preferably from 200 to 400.
• the density of open channels and closed channels is from 200 to 400 channels per square inch.
• the channels can have cross sections that are rectangular, square, circular, oval, triangular, hexagonal, or other polygonal shapes.
• the catalytic layer may be coated on the inlet side (21 ) of the porous walls of the filter, the outlet side (22) of the porous walls of the filter, or both sides (21 and 22).
• the loading may be characterized as "on wall” loading or "in wall” loading.
• the former is characterized by the formation of a catalytic layer on a surface of the porous walls (15).
• the latter is characterized by extending partial of the catalytic layer thorough the thickness of the porous walls (15).
• the mean pore size of the particulate filter is from 8 to 24 pm, preferably 10 to 20 pm.
• the PGM is present in a catalytically effective amount to convert NOx, CO and hydrocarbons in an exhaust gas to Na, CO 2 and H 2 O and to cause the oxidation of particulate matter trapped on the particulate filter.
• the particulate filter comprises 0-30 g/ft 3 of rhodium, 0- 100 g/ft 3 of platinum, and 0-100 g/ft 3 of palladium, calculated as the metal.
• the catalytic layer contains PGM with a total precious metal loading in the range of 2 to 125 g/ft 3 , calculated as the metal.
• the first zone comprises palladium and rhodium
• the second zone comprises palladium
• the third zone comprises palladium and rhodium.
• the first zone comprises platinum and rhodium
• the second zone comprises platinum
• the third zone comprises platinum and rhodium
• the first zone comprises platinum and palladium
• the second zone comprises platinum
• the third zone comprises platinum and palladium
• the first zone comprises platinum and palladium
• the second zone comprises palladium
• the third zone comprises platinum and palladium
• the first zone comprises palladium and rhodium
• the second zone comprises rhodium
• the third zone comprises palladium and rhodium.
• the first zone comprises platinum and rhodium
• the second zone comprises rhodium
• the third zone comprises platinum and rhodium
• the first zone comprises platinum, palladium and rhodium
• the second zone comprises platinum
• the third zone comprises platinum, palladium and rhodium.
• the first zone comprises platinum, palladium and rhodium
• the second zone comprises palladium
• the third zone comprises platinum, palladium and rhodium.
• the first zone comprises platinum, palladium and rhodium
• the second zone comprises rhodium
• the third zone comprises platinum, palladium and rhodium.
• the first zone comprises platinum, palladium and rhodium
• the second zone comprises platinum and palladium
• the third zone comprises platinum, palladium and rhodium.
• the first zone comprises platinum, palladium and diodium
• the second zone comprises palladium and rhodium
• the third zone comprises platinum, palladium and rhodium.
• the first zone comprises platinum, palladium and rhodium
• the second zone comprises platinum and rhodium
• the third zone comprises platinum, palladium and rhodium.
• the catalytic layer comprises from about 50 wt.% to about 99.9 wt.%, including about 60 wt.% to about 99.8 wt.%, including about 70 wt.% to about 99.6 wt.% of hydrothermally stable support material, based on the calcined weight of the catalytic layer.
• the catalytic layer may, for example, comprise from about 5 to about 90 wt.% of alumina, preferably from about 10 to about 75 wt.% of alumina, based on the calcined weight of the catalytic layer.
• the catalytic layer may, for example, comprise from about 5 to about 70 wt.% of zirconia, preferably from about 10 to about 40 wt.% of zirconia, based on the calcined weight of the catalytic layer.
• the catalytic layer may, for example, comprise from about 5 to about 60 wt.% of ceria, preferably from about 10 to about 30 wt.% of ceria, based on the calcined weight of the catalytic layer.
• the particle size distribution of the hydrothermally stable support material in the catalytic layer in this invention is in the range of 500 nm to 50 pm.
• the specific surface area of said hydrothermally stable support material is in the range of 30-200 m 2 /g at fresh state and 10-150 m 2 /g after 4hr calcination in air at 1000°C.
• the catalytic layer of the invention are loaded onto a filter at a loading in the range of at least about 5 g/L, about 10 g/L, about 15 g/L, about 20 g/L, about 25 g/L or about 30 g/L up to about 150 g/L, about 175 g/L, about 200 g/L, about 225 g/L, about 250 g/L about 275 g/L, about 300 g/L or about 325 g/L. It is to be understood that each lower endpoint and each higher endpoint disclosed in the foregoing may be combined to form a catalytic layer loading range that is expressly contemplated by the invention. In certain exemplary embodiments, the catalytic layer loading is in the range of 10 to 170 g/L.
• the first length (L1 ) extends for 15-45% of the total substrate length (L); the third length (L3) extends for 15-45% of the total substrate length (L). In specific embodiments, the first length (L1 ) extends for 20-45% of the total substrate length (L); In more specific embodiments, the first length (L1) extends for 25- 40% of the total substrate length (L); the third length (L3) extends for 25-40% of the total substrate length (L).
• the particulate filter is canned. In an alternative embodiment, the filter is uncanned. Being “canned” means that the particulate filter has been incorporated into a housing for incorporation into an emission treatment system.
• the particulate filter Being “uncanned” means that the particulate filter has not yet been incorporated into a housing for incorporation into an emission treatment system but is still coated with the catalytic layer, to a typical canning process, the particulate filter is sleeved in a support mat, typically formed of ceramic fibers or alumina fibers, before being incorporated into a metal housing.
• Methods of incorporating the particulate filter into a metal housing include, for example, "clam-shell", “stuffing and “tourniquet” techniques. Such techniques are known in the art.
• a system for exhaust gas treatment from an internal combustion engine comprising: the catalyzed particulate filter, and one or more of a selective catalytic reduction (SCR) catalyst, a three way conversion (TWC) catalyst, a diesel oxidation catalyst (DOC), an ammonia oxidation (AMOx) catalyst, a NOx trap, a NOx absorber catalyst, a hydrocarbon trap catalyst.
• SCR selective catalytic reduction
• TWC three way conversion
• DOC diesel oxidation catalyst
• AMOx ammonia oxidation
• NOx trap NOx trap
• NOx absorber catalyst a hydrocarbon trap catalyst
• SCR selective catalytic reduction
• the SCR catalyst may include at least one material selected front: MOR; USY; ZSM-5; ZSM-20; beta-zeolite; CHA; LEV; AEI; AFX; FER; SAPO; ALPO; vanadium; vanadium oxide; titanium oxide; tungsten oxide; molybdenum oxide; cerium oxide; zirconium oxide; niobium oxide; iron; iron oxide; manganese oxide; copper; molybdenum; tungsten; and mixtures thereof.
• the support structures for the active components of the SCR catalyst may include any suitable zeolite, zeotype, or non- zeolitic compound.
• the SCR catalyst may include a metal, a metal oxide, or a mixed oxide as the active component.
• Transition metal loaded zeolites e.g., copper-chabazite, or Cu-CHA, as well as copper-levyne, or Cu-LEV, as well as Fe- Beta
• zeotypes e.g., copper-SAPO, or Cu-SAPO are preferred.
• a TWC catalyst mainly comprises a platinum group metal (PGM), an oxygen storage component (OSC), and a refractory metal oxide support.
• platinum group metal and “PGM” refer to one or more chemical elements defined in the Periodic Table of Elements, including platinum, palladium, rhodium, osmium, iridium, and ruthenium, and mixtures thereof.
• the platinum group metal component of the TWC catalyst is selected from platinum, palladium, rhodium, or mixtures thereof.
• the platinum group metal component of the TWO catalyst comprises palladium.
• the TWC catalyst does not comprise an additional platinum group metal (i.e., the TWC comprises only one platinum group metal). In other embodiments, the TWC catalyst comprises an additional platinum group metal. In one or more embodiments, when present, the additional platinum group metal is selected from platinum, rhodium, and mixtures thereof. In specific embodiments, the additional platinum group metal component comprises rhodium. In one or more specific embodiments, the TWC catalyst comprises a mixture of palladium and rhodium. In other embodiments, the TWC catalyst comprises a mixture of platinum, palladium, and rhodium.
• oxygen storage component and “OSC” refer to an entity that has a multi-valence state and can actively react with reductants such as CO or hydrogen under reduction conditions and then react with oxidants such as oxygen or nitrogen oxides under oxidative conditions.
• oxygen storage components include rare earth oxides, particularly ceria, lanthana, praseodymia, neodymia, niobia, europia, samaria, ytterbia, yttria, zirconia, and mixtures thereof in addition to ceria.
• the rare earth oxide may be in bulk (e.g. particulate) form.
• the oxygen storage component can include ceria in a form that exhibits oxygen storage properties.
• the lattice oxygen of ceria can react with carbon monoxide, hydrogen, or hydrocarbons under rich A/F conditions.
• the oxygen storage component for the TWC catalyst comprises a ceria-zirconia composite or a rare earth- stabilized ceria-zirconia.
• refractory metal oxide support and “support” refer to underlying high surface area material upon which additional chemical compounds or elements are carried.
• the support particles have pores larger than 20 A and a wide pore distribution.
• such supports e.g., metal oxide supports, exclude molecular sieves, specifically, zeolites.
• high surface area refractory metal oxide supports can be utilized, e.g., alumina support materials, also referred to as “gamma alumina” or “activated alumina,” which typically exhibit a BET surface area in excess of 60 square meters per gram (“m 2 /g”), often up to about 200 m 2 /g or higher.
• Such activated alumina is usually a mixture of the gamma and delta phases of alumina, but may also contain substantial amounts of eta, kappa, and theta alumina phases.
• Refractory metal oxides other than activated alumina can be used as a support for at least some of the catalytic components in a given catalyst. For example, bulk ceria, zirconia, alpha alumina, silica, titania, and other materials are known for such use.
• the refractory metal oxide supports for the TWC catalyst independently comprise a compound that is activated, stabilized, or both, selected from the group consisting of alumina, zirconia, alumina-zirconia, lanthana-alumina, lanthana-zirconia-alumina, alumina-chromia, ceria, alumina-ceria, and combinations thereof.
• diesel oxidation catalyst and “DOC” refer to diesel oxidation catalysts, which are well-known in the art. Diesel oxidation catalysts are designed to oxidize CO to CO 2 and gas phase HC and an organic fraction of diesel particulates (soluble organic fraction) to CO 2 and H2O. Typical diesel oxidation catalysts include platinum and optionally also palladium on a high surface area inorganic oxide support, such as alumina, silica-alumina, titania, silica-titania, and a zeolite. As used herein, the term includes a DEC (Diesel Exotherm Catalyst) which creates an exotherm.
• DEC Diesel Exotherm Catalyst
• ammonia oxidation catalyst and “AMOx” refer to catalysts comprise at least a supported precious metal component, such as one or more platinum group metals (PGMs), which is effective to remove ammonia from an exhaust gas stream.
• PGMs platinum group metals
• the precious metal may include platinum, palladium, rhodium, ruthenium, iridium, silver or gold.
• the precious metal component includes physical mixtures or chemical or atomically-doped combinations of precious metals.
• the precious metal component is typically deposited on a high surface area refractory met-al oxide support.
• suitable high surface area refractory metal oxides include alumina, silica, titania, ceria, and zirconia, magnesia, barium oxide, manganese oxide, tungsten oxide, and rear earth metal oxide rear earth metal oxide, base metal oxides, as well as physical mixtures, chemical combinations and/or atomically-doped combinations thereof.
• NOx adsorbed catalyst and “NOx trap (also called Lean NOx trap, abbr. LNT)” refer to catalysts for reducing oxides of nitrogen (NO and NO 2 ) emissions from a lean burn internal combustion engine by means of adsorption.
• Typical NOx trap includes alkaline earth metal oxides, such as oxides of Mg, Ca, Sr and Ba, alkali metal oxides such as oxides of Li, Na, K, Rb and Cs, and rare earth metal oxides such as oxides of Ce, La, Pr and Nd in combination with precious metal catalysts such as platinum dispersed on an alumina support have been used in the purification of exhaust gas from an internal combustion engine.
• baria is usually preferred because it forms nitrates at lean engine operation and releases the nitrates relatively easily under rich conditions.
• hydrocarbon trap refers to catalysts for trapping hydrocarbons during cold operation periods and releasing them for oxidation during higher-temperature operating periods.
• the hydrocarbon trap may be provided by one or more hydrocarbon (HC) storage components for the adsorption of various hydrocarbons (HC).
• hydrocarbon storage material having minimum interactions of precious metals and the material can be used, e.g., a micro-porous material such as a zeolite or zeolite-like material.
• the hydrocarbon storage material is a zeolite.
• Beta zeolite is particularly preferable since large pore opening of beta zeolite allows hydrocarbon molecules of diesel derived species to be trapped effectively.
• zeolites such as faujasite, chabazite, clinoptilolite, mordenite, silicalite, zeolite X, zeolite Y, ultrastable zeolite Y, ZSM-5 zeolite, offretite, can be used in addition to the beta zeolite to enhance HC storage in the cold start operation.
• a method for preparing the catalyzed particulate filter comprises the steps of:
• aqueous slurry comprising a first PGM, optionally using one or more precursors thereof, and a support material;
• the precursor of the first PGM may be in the form of a chloride, nitrate, acetate, ammonia or amine complex hydroxide solution, or in the form of highly dispersed colloidal metal dispersion.
• the second PGM may be in the form of a chloride, nitrate, acetate, ammonia or ammine complex hydroxide solution, or in the form of a highly dispersed colloidal metal dispersion.
• the calcination temperature in step 3) and 5) could independently be from 250°C to 1000°C, preferably from 300°C to 700 o C, more preferably from 450°C to 650°C.
• the calcination period may be from 10 minutes to 10 hours, preferably 0.5 hour to 8 hours, more preferably 1 hour to 4 hours.
• Other aspects include methods for the treatment of exhaust gas from an internal combustion engine comprising: providing the particulate filter; and flowing the exhaust gas from the engine through the particulate filter.
• the exhaust gas comprises unburnt hydrocarbons, carbon monoxide, nitrogen oxides, and particulate matter.
• Embodiment 1 A catalyzed particulate filter for exhaust gas treatment from an internal combustion engine comprising:
• a particulate filter comprising a porous substrate having a total substrate length (L) an inlet surface, an outlet surface, an inlet axial end, an outlet axial end;
• a catalytic layer comprising a support material, and at least one platinum group metal (PGM) selected from platinum, palladium and rhodium; the catalytic layer being coated onto the inlet side, the outlet side, or both sides of the particulate filter; wherein the catalytic layer comprises a first zone, a second zone, and a third zone; the first zone begins at the inlet axial end and has a first length (L1 ) extending for 10- 45% of the total substrate length (L); the third zone begins at the outlet axial end and has a third length (L3) extending for 10-45% of the total substrate length (L); the second zone begins at the axial end of first zone, ends at the axial beginning of the third zone; and wherein the content of PGM in the first zone is higher than the content of PGM in the second zone, and the content of PGM in the third zone is higher than the content of PGM in the second zone, calculated as the weight of platinum group metal per zone volume.
• PGM platinum group metal
• Embodiment 2 The catalyzed particulate filter according to Embodiment 1 , wherein the particulate filter is a wall-flow filter comprising a honeycomb structure.
• Embodiment 3 The catalyzed particulate filter according to Embodiment 1 or 2, wherein the mean pore size of the particulate filter is from 8 to 24 pm, preferably 10 to 20 pm.
• Embodiment 4 The catalyzed particulate filter according to any one of Embodiments 1 to 3, wherein the PGM is present in a catalytically effective amount to convert NOx, CO and hydrocarbons in an exhaust gas to N 2 , CO 2 and H 2 O and to cause the oxidation of particulate matter trapped on the particulate filter.
• Embodiment 5 The catalyzed particulate filter according to any one of Embodiments 1 to 4, wherein the particulate filter comprises 0-30g / ft 3 of rhodium, 0-100 g/ft 3 of platinum, and 0-100 g/ft 3 of palladium, calculated as the metal.
• Embodiment 6 The catalyzed particulate filter according to any one of Embodiments 1 to 5, wherein the catalytic layer has a loading in the range of 10 to 170 g/L.
• Embodiment 7 The catalyzed particulate filter according to any one of Embodiments 1 to 6, wherein the first length (L1) extends for 15-45% of the total substrate length (L); the third length (L3) extends for 15-45% of the total substrate length (L).
• Embodiment 8 A system for exhaust gas treatment from an internal combustion engine comprising: the catalyzed particulate filter according to any one of Embodiments 1 to 7, and one or more of a selective catalytic reduction (SCR) catalyst, a three way conversion (TWC) catalyst, a diesel oxidation catalyst (DOC), an ammonia oxidation (AMOx) catalyst, a NOx trap, a NOx absorber catalyst, a hydrocarbon trap catalyst.
• SCR selective catalytic reduction
• TWC three way conversion
• DOC diesel oxidation catalyst
• AMOx ammonia oxidation
• NOx trap a NOx trap
• NOx absorber catalyst a hydrocarbon trap catalyst
• hydrocarbon trap catalyst a hydrocarbon trap catalyst
• aqueous slurry comprising a first PGM, optionally using one or more precursors thereof, and a support material;
• Embodiment 10 A method for the treatment of exhaust gas from an internal combustion engine comprising:
• Embodiment 11 The method according to Embodiment 10, wherein the exhaust gas comprises unburned hydrocarbons, carbon monoxide, nitrogen oxides, and particulate matter.
• the present invention is further illustrated by the following examples, which are set forth to illustrate the present invention and is not to be construed as limiting thereof. Unless otherwise noted, all parts and percentages are by weight, and all weight percentages are expressed on a dry basis, meaning excluding water content, unless otherwise indicated. In each of the examples, the filter substrate was made of cordierite.
• the Example 1 was prepared using a single coat from inlet side of a wall-flow filter substrate.
• the wall-flow filter substrate had a size of 118.4 mm (D)*127 mm (L), a volume of 1.40 L, a cell density of 300 cells per square inch, a wall thickness of approximately 200 pm, a porosity of 65% and a mean pore size of 18 pm in diameter by mercury intrusion measurements.
• the Pd/Rh catalytic layer coated onto the substrate contains a prior art three-way conversion (TWC) catalyst composite.
• TWC three-way conversion
• the PGM distribution layouts is illustrated in FIG. 2(a).
• the catalytic layer was prepared as following:
• Palladium in the form of a palladium nitrate solution was impregnated by planetary mixer onto a refractory alumina and a stabilized ceria-zirconia composite with approximately 40 wt.% ceria to form a wet powder while achieving incipient wetness.
• Rhodium in the form of a rhodium nitrate solution was impregnated by planetary mixer onto a refractory alumina and a stabilized ceria-zirconia composite with approximately 40 wt.% ceria to form a wet powder white achieving incipient wetness.
• aqueous slurry was formed by adding the above powders into water, followed by addition of barium hydroxide and zirconium nitrate solution. The slurry was then milled to a particle size of 90% being 5 pm. The slurry was then coated from the inlet side of the wall-flow filter substrate and covering the total substrate length using deposition methods known in the art. After coating, the filter substrate plus the inlet coat were dried at 150°C and then calcined at a temperature of 550°C for about 1 hour.
• the calcined Pd/Rh catalytic layer was having 24.8 wt.% alumina, 68.5 wt.% ceria-zirconia composite, 0.47 wt.% palladium, 0.23 wt.% rhodium, 4.6 wt.% of barium oxide and 1.4 wt.% zirconia oxide.
• the total loading of the catalytic layer was 1 .24 g/in 3 .
• Example 2 is a particulate filter having a first Pd catalytic layer with a Pd loading of 15 g/ft 3 , coated onto the substrate from inlet side and covering the total substrate length; and a second Rh catalytic component with a local Rh loading of 33.3 g/ft 3 , coated onto the substrate from inlet side and covering 30% of the total substrate length.
• the PGM distribution layouts is illustrated in FIG. 2(b).
• the wall-flow filter substrate had a size of 118.4 mm (D)*127 mm (L), a volume of 1.40 L, a cell density of 300 cells per square inch, a wall thickness of approximately 200 pm, a porosity of 65% and a mean pore size of 18 pm in diameter by mercury intrusion measurements.
• the first Pd catalytic layer was prepared as following:
• Palladium in the form of a palladium nitrate solution was impregnated by planetary mixer onto a refractory alumina and a stabilized ceria-zirconia composite with approximately 40 wt.% ceria to form a wet powder while achieving incipient wetness.
• An aqueous slurry was formed by adding the above powders into water, followed by addition of barium hydroxide and zirconium nitrate solution. The slurry was then milled to a particle size of 90% being 5 pm. The slurry was then coated from the inlet side of the wall-flow filter substrate using deposition methods known in the art to cover 100% of the total substrate length.
• the filter substrate plus the inlet coat were dried at 150°C and then calcined at a temperature of 550°C for about 1 hour.
• the calcined Pd catalytic layer was having 24.8 wt.% alumina, 68.5 wt.% ceria-zirconia composite, 0.70 wt.% palladium, 4.6 wt.% of barium oxide and 1 .4 wt.% zirconia oxide.
• the total loading of the catalytic layer was 1.24 g/in 3 for 100% of the total substrate volume.
• the second Rh catalytic component was prepared as following:
• rhodium in the form of a rhodium nitrate solution, was deposited such that it covers 30% of the substrate length from the inlet axial end of the filter.
• the substrate already contains the first Pd catalytic layer.
• the filter was dried at 150°C and then calcined at a temperature of 550°C for about 1 hour in air.
• Example 3 was prepared in the similar way as Example 2, except that the second Rh catalytic component was deposited from outlet axial end to cover 30% of the substrate length from outlet side.
• the PGM distribution layouts is illustrated in FIG. 2(c).
• Example 4 is a particulate filter having a first Pd catalytic layer with a Pd loading of 15 g/ft 3 , coated onto the substrate from inlet side and covering the total substrate length; and a second Rh catalytic component with a local Rh loading of 50 g/ft 3 , coated onto the substrate from both inlet and outlet side and covering, at both sides, 10% of the total substrate length.
• the PGM distribution layouts is illustrated in FIG. 2(d).
• Example 4 was prepared in the similar way as Example 2, except that the second Rh catalytic component was deposited from both inlet and outlet axial end to cover 10% of the substrate length from each side.
• Example 5 was prepared in the similar way as Example 4, except that the covering length of the second Rh catalytic component is 15% of the substrate length from both inlet and outlet axial end.
• the PGM distribution layouts is illustrated in FIG. 2(e).
• Example 6 was prepared in the similar way as Example 4, except that the covering length of the second Rh catalytic component is 30% of the substrate length from both inlet and outlet axial end.
• the PGM distribution layouts is illustrated in FIG. 2(f).
• Example 7 was prepared in the similar way as Example 4, except that the covering length of the second Rh catalytic component is 45% of the substrate length from both inlet and outlet axial end.
• the PGM distribution layouts is illustrated in FIG. 2(g).
• the emission performance was tested using a 2.0L turbo-charged engine with a CC- only emission control system configuration operating under the WLTC test protocol. Each catalytic filter was tested at least three times to assure high experiment repeatability and data consistence.
• FIG. 5 An optimal way of using the solution absorption for platinum group metal, in this case, rhodium, in filter catalyst, is exhibited in FIG. 5.
• the best performers, invention catalyst Examples 5 to 7, are showing up to -20% THC, - 20% CO, and -25% NO X improvement in the WLTC test compared to reference Example 1 at the same platinum group metal loading without a change in the washcoat support formulation. This is attributed to carefully designed rhodium enrichment zone, by PGM solution absorption, at both inlet and outlet axial ends and with an optimal zone length.
• the Example 9 was prepared using a single coat from inlet side of a wall-flow filter substrate.
• the wall-flow filter substrate had a size of 118.4 mm (D)*127 mm (L), a volume of 1.40 L, a cell density of 300 cells per square inch, a wall thickness of approximately 200 pm, a porosity of 65% and a mean pore size of 18 pm in diameter by mercury intrusion measurements.
• the Pd/Rh catalytic layer coated onto the substrate contains a prior art three-way conversion (TWC) catalyst composite.
• TWC three-way conversion
• the PGM distribution layouts is illustrated in FIG. 3(a).
• the catalytic layer was prepared as following:
• Palladium in the form of a palladium nitrate solution was impregnated by planetary mixer onto a refractory alumina and a stabilized ceria-zirconia composite with approximately 40 wt.% ceria to form a wet powder while achieving incipient wetness.
• Rhodium in the form of a rhodium nitrate solution was impregnated by planetary mixer onto a refractory alumina and a stabilized ceria-zirconia composite with approximately 40 wt.% ceria to form a wet powder while achieving incipient wetness.
• aqueous slurry was formed by adding the above powders into water, followed by addition of barium hydroxide and zirconium nitrate solution. The slurry was then milled to a particle size of 90% being 5 pm. The slurry was then coated from the inlet side of the wall-flow filter substrate and covering the total substrate length using deposition methods known in the art. After coating, the filter substrate plus the inlet coat were dried at 150°C and then calcined at a temperature of 550°C for about 1 hour.
• the calcined Pd/Rh catalytic layer was having 24.8 wt.% alumina, 68.5 wt.% ceria-zirconia composite, 0.47 wt.% palladium, 0.23 wt.% rhodium, 4.6 wt.% of barium oxide and 1.4 wt.% zirconia oxide.
• the total loading of the catalytic layer was 1.24 g/in 3 .
• Example 10 is a particulate filter having a first Rh catalytic layer with a Rh loading of 5 g/ft 3 , coated onto the substrate from inlet side and covering the total substrate length; and a second Pd catalytic component with a local Pd loading of 33.3 g/ft 3 , coated onto the substrate from both inlet axial end and outlet axial end and each covering 30% of the total substrate length.
• the PGM distribution layouts is illustrated in FIG. 3(b).
• the first Rh catalytic layer was prepared as following:
• Rhodium in the form of a rhodium nitrate solution was impregnated by planetary mixer onto a refractory alumina and a stabilized ceria-zirconia composite with approximately 40 wt.% ceria to form a wet powder while achieving incipient wetness.
• An aqueous slurry was formed by adding the above powders into water, followed by addition of barium hydroxide and zirconium nitrate solution. The slurry was then milled to a particle size of 90% being 5 pm. The slurry was then coated from the inlet side of the wall-flow filter substrate using deposition methods known in the art to cover 100% of the total substrate length.
• the filter substrate plus the inlet coat were dried at 150°C and then calcined at a temperature of 550°C for about 1 hour.
• the calcined Rh catalytic layer was having 24.9 wt.% alumina, 68.9 wt.% ceria-zirconia composite, 0.23 wt.% rhodium, 4.6 wt.% of barium oxide and 1 .4 wt.% zirconia oxide.
• the total loading of the catalytic layer was 1.23 g/in 3 for 100% of the total substrate volume.
• the second Pd catalytic component was prepared as following:
• Both catalysts prepared in examples 9 and 10 were aged under an exothermic ageing protocol using an engine setup to operate such that the typical inlet temperature is ⁇ 875°C and the typical catalyst bed temperature is ⁇ 925°C and does not exceed ⁇ 980°C.
• the engine-out gas feed composition alternates between rich and lean to simulate typical operating conditions for a vehicle durability test.
• Ail catalytic filters were aged using the same conditions for 100 hours.
• the emission performance was tested using a 1 .5L turbo-charged engine with a CC- oniy emission control system configuration operating under the WLTC test protocol. Each catalytic filter was tested at least three times to assure high experiment repeatability and data consistence.
• the invention catalyst Example 10 achieved -10-15% THC and NO X improvement in the WLTC test compared to the reference Example 9, at same washcoat loading and total PGM loading.
• the Example 12 was prepared using a single coat from inlet side of a wall-flow filter substrate.
• the wall-flow filter substrate had a size of 118.4 mm (D)*127 mm (L), a volume of 1.40 L, a cell density of 300 cells per square inch, a wall thickness of approximately 200 pm, a porosity of 65% and a mean pore size of 18 pm in diameter by mercury intrusion measurements.
• the Pt/Rh catalytic layer coated onto the substrate contains a prior art three-way conversion (TWC) catalyst composite.
• TWC three-way conversion
• the PGM distribution layouts is illustrated in FIG. 4(a).
• the catalytic layer was prepared as following:
• Platinum in the form of a platinum tetraamine oxide solution was impregnated by planetary mixer onto a refractory alumina and a stabilized ceria-zirconia composite with approximately 40 wt.% ceria to form a wet powder while achieving incipient wetness.
• Rhodium in the form of a rhodium nitrate solution was impregnated by planetary mixer onto a refractory alumina and a stabilized ceria-zirconia composite with approximately 40 wt.% ceria to form a wet powder while achieving incipient wetness.
• aqueous slurry was formed by adding the above powders into water, followed by addition of barium hydroxide and zirconium nitrate solution. The slurry was then milled to a particle size of 90% being 5 pm. The slurry was then coated from the inlet side of the wall-flow filter substrate and covering the total substrate length using deposition methods known in the art. After coating, the filter substrate plus the inlet coat were dried at 150°C and then calcined at a temperature of 550°C for about 1 hour.
• the calcined Pt/Rh catalytic layer was having 24.7 wt.% alumina, 68.2 wt.% ceria- zirconia composite, 0.70 wt.% platinum, 0.47 wt.% rhodium, 4.6 wt.% of barium oxide and 1 .4 wt.% zirconia oxide.
• the total loading of the catalytic layer was 1 .24 g/in 3 .
• Example 13 is a particulate filter having a first Rh catalytic layer with a Rh loading of 10 g/ft 3 , coated onto the substrate from inlet side and covering the total substrate length; and a second Pt catalytic component with a local Pt loading of 25 g/ft 3 , coated onto the substrate from both inlet axial end and outlet axial end and each covering 30% of the total substrate length.
• the PGM distribution layouts is illustrated in FIG. 4(b).
• the first Rh catalytic layer was prepared as following:
• Rhodium in the form of a rhodium nitrate solution was impregnated by planetary mixer onto a refractory alumina and a stabilized ceria-zirconia composite with approximately 40 wt.% ceria to form a wet powder while achieving incipient wetness.
• An aqueous slurry was formed by adding the above powders into water, followed by addition of barium hydroxide and zirconium nitrate solution. The slurry was then milled to a particle size of 90% being 5 pm. The slurry was then coated from the inlet side of the wail-flow filter substrate using deposition methods known in the art to cover 100% of the total substrate length.
• the filter substrate plus the inlet coat were dried at 150°C and then calcined at a temperature of 550°C for about 1 hour.
• the calcined Rh catalytic layer was having 24.8 wt.% alumina, 68.7 wt.% ceria-zirconia composite, 0.47 wt.% rhodium, 4.6 wt.% of barium oxide and 1 .4 wt.% zirconia oxide.
• the total loading of the catalytic layer was 1 .23 g/ln 3 for 100% of the total substrate volume.
• the second Pt catalytic component was prepared as following:
• Both catalysts prepared in examples 12 and 13 were aged under an exothermic ageing protocol using an engine setup to operate such that the typical inlet temperature is ⁇ 875°C and the typical catalyst bed temperature is TM925°C and does not exceed ⁇ 980°C.
• the engine-out gas feed composition alternates between rich and lean to simulate typical operating conditions for a vehicle durability test. All catalytic filters were aged using the same conditions for 150 hours.
• the emission performance was tested using a 2.0L turbo-charged engine with a CC- only emission control system configuration operating under the WLTC test protocol. Each catalytic filter was tested at least three times to assure high experiment repeatability and data consistence.
• the invention catalyst Example 13 achieved -7% CO and -20% NO X improvement in the WLTC test compared to the reference Example 12, at same washcoat loading and total PGM loading.

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