EP0170841A1
Expired / Lapsed
EP
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Stabilized and doubly promoted platinum group metal catalysts for emission control
Assignee: WR Grace and Co
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Filing: 1985-06-20
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Granted: —
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Expires: 2005-06-20
Abstract
Abstract Alumina supported platinum-group metal catalysts exhibit exceptionally good performance and durability when the support is sequentially modified to include support stabilization by lanthana or lanthana-rich rare earth oxides, double promotion by ceria and alkali metal oxides, especially ceria along with lithia, and optionally nickel (oxide) as a base metal catalytic ingredient. For a pelleted Rh containing catalyst to exhibit such an outstanding performance at least part of the Rh component is added separately from any other Pt group metals.
Inventors
- 👤 Gwan Kim
- 👤 Michael Vance Ernest
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-01 04:03
CPC Classifications
B; B01; B01J; B01J23/00; B01J23/38; B01J23/54; B01J23/56; B01J23/63; B01D; B01D53/00; B01D53/34; B01D53/92; B01D53/94; B01D53/9445; B01D53/945; B01J23/58; Y; Y02; Y02T; Y02T10/00; Y02T10/10; Y02T10/12
Claims Analysis
Total Claims: 26
Claim 1
Independent Claim
107 words
A catalyst suitable for use as a catalyst for auto emission control comprising an alumina support having impregnated thereon about 1 to 10% by weight expressed as La 2 0 3 of lanthana as a stabilizer which is either in the form of lanthana only or in the form of lanthana-rich rare earth oxides where the La 2 0 3 is at least 50% by weight of the total rare earth oxides, 1-20% by weight of ceria as a promoter, at least 0.5 to about 5% by weight of an alkali metal oxide as a promoter, and a catalytically-effective amount of one or more platinum group metals.
Claim 2
Dependent Claim
107 words
A catalyst suitable for use as a catalyst for auto emission control comprising an alumina support having impregnated thereon about 1 to 10% by weight expressed as La 2 0 3 of lanthana as a stabilizer which is either in the form of lanthana only or in the form of lanthana-rich rare earth oxides where the La 2 0 3 is at least 50% by weight of the total rare earth oxides, 1-20% by weight of ceria as a promoter, at least 0.5 to about 5% by weight of an alkali metal oxide as a promoter, and a catalytically-effective amount of one or more platinum group metals.
Claim 3
Dependent Claim
39 words
A catalyst according to Claim 1, wherein the alumina support is pelleted and said platinum group metals penetrate the alumina support to an average distance less than approximately 300 microns as measured by the SnCl 2 solution staining method.
Claim 4
Dependent Claim
30 words
A catalyst according to Claim 1, wherein the alkali metal oxide is Li 2 0 and wherein the lanthana expressed as La 2 0 3 is about 2-6% by weight.
Claim 5
Dependent Claim
17 words
A catalyst according to Claim 2, wherein the platinum group metals comprise at least platinum and rhodium.
Claim 6
Dependent Claim
14 words
A catalyst according to Claim 1, wherein the alumina support is a washcoat powder.
Claim 7
Dependent Claim
77 words
A catalyst according to Claim 4, wherein a maximum of the platinum is within about 50 microns of the exterior surface of the support and no more than about 70% of the total platinum loaded is located within about 100 microns depth and a maximum rhodium concentration is within about 50 microns of the exterior surface of the support and no more than about 95% of the total rhodium loaded is located without about 100 microns depth.
Claim 8
Dependent Claim
20 words
A catalyst according to Claim 1, wherein nickel is further added in an amount of 0.5 to 20 wt.% NiO.
Claim 9
Dependent Claim
160 words
A catalyst suitable for use as a three-way catalyst for auto emission control comprising an alumina pelleted support having impregnated thereon 1-20% by weight of ceria as a promoter, at least 0.5 to about 5% by weight of an alkali metal oxide as a promoter, and a catalytically-effective amount of one or more platinum group metals comprising at least platinum and rhodium, said platinum group metals penetrating the alumina support to an average distance less than approximately 300 microns as measured by the SnCl 2 solution staining method, said platinum having a maximum concentration within about 50 microns of the exterior surface of the support but no more than about 70% of the total platinum loaded being located within about 100 microns depth and said rhodium having a maximum rhodium concentration within about 50 microns of the exterior surface of the support but no more than about 80% of the total rhodium loaded being located within about 100 microns depth.
Claim 10
Dependent Claim
160 words
A catalyst suitable for use as a three-way catalyst for auto emission control comprising an alumina pelleted support having impregnated thereon 1-20% by weight of ceria as a promoter, at least 0.5 to about 5% by weight of an alkali metal oxide as a promoter, and a catalytically-effective amount of one or more platinum group metals comprising at least platinum and rhodium, said platinum group metals penetrating the alumina support to an average distance less than approximately 300 microns as measured by the SnCl 2 solution staining method, said platinum having a maximum concentration within about 50 microns of the exterior surface of the support but no more than about 70% of the total platinum loaded being located within about 100 microns depth and said rhodium having a maximum rhodium concentration within about 50 microns of the exterior surface of the support but no more than about 80% of the total rhodium loaded being located within about 100 microns depth.
Claim 11
Dependent Claim
21 words
A catalyst according to Claim 8, wherein nickel is further added in an amount of 0.5 to 20 wt. % NiO.
Claim 12
Independent Claim
302 words
A method of making a catalyst which is suitable for use as a three-way catalyst for auto emission comprising the steps of a) impregnating an alumina support which has been heated to at least 300 0 C with a solution containing a lanthanum salt which is either in the form of lanthanum salt only or in the form of lanthanum-rich rare earth salts, which upon calcination gives rare earth oxides where La 2 0 3 is at least 50% by weight of the total rare earth oxides; b) heating the impregnated support to at least decompose the lanthanum salt to obtain a lanthana impregnated support; c) applying promoters and one or more platinum group metals by either A 1) impregnating the lanthana-impregnated alumina support from step (b) with a soluble cerium salt solution; 2) heating the impregnated support to at least decompose the cerium salt to obtain a lanthana-ceria impregnated support; and 3) impregnating the lanthana-ceria impregnated support with solutions bearing one or more platinum group metals and at least one alkali metal; or B 1) impregnating the lanthana impregnated support from step (b) with a solution containing a soluble cerium salt and a lithium salt; 2) heating the impregnated support to at least decompose the cerium and lithium salts to obtain a lanthana-ceria-lithia impregnated support; and 3) impregnating the lanthana-ceria-lithia impregnated support with solutions bearing one or more platinum group metals to form a catalyst; d) air drying the catalyst at ambient temperature for 0-4 hours, and at about 100-150°C to dry the catalyst after each impregnation with solutions bearing catalytic metals; and e) activating the catalyst, which has previously been heated to a temperature of at least 800-1100°C in one of the prior steps (b) or (c), at a temperature of about 250-550°C and preferably in the presence of hydrogen.
Claim 13
Independent Claim
302 words
A method of making a catalyst which is suitable for use as a three-way catalyst for auto emission comprising the steps of a) impregnating an alumina support which has been heated to at least 300 0 C with a solution containing a lanthanum salt which is either in the form of lanthanum salt only or in the form of lanthanum-rich rare earth salts, which upon calcination gives rare earth oxides where La 2 0 3 is at least 50% by weight of the total rare earth oxides; b) heating the impregnated support to at least decompose the lanthanum salt to obtain a lanthana impregnated support; c) applying promoters and one or more platinum group metals by either A 1) impregnating the lanthana-impregnated alumina support from step (b) with a soluble cerium salt solution; 2) heating the impregnated support to at least decompose the cerium salt to obtain a lanthana-ceria impregnated support; and 3) impregnating the lanthana-ceria impregnated support with solutions bearing one or more platinum group metals and at least one alkali metal; or B 1) impregnating the lanthana impregnated support from step (b) with a solution containing a soluble cerium salt and a lithium salt; 2) heating the impregnated support to at least decompose the cerium and lithium salts to obtain a lanthana-ceria-lithia impregnated support; and 3) impregnating the lanthana-ceria-lithia impregnated support with solutions bearing one or more platinum group metals to form a catalyst; d) air drying the catalyst at ambient temperature for 0-4 hours, and at about 100-150°C to dry the catalyst after each impregnation with solutions bearing catalytic metals; and e) activating the catalyst, which has previously been heated to a temperature of at least 800-1100°C in one of the prior steps (b) or (c), at a temperature of about 250-550°C and preferably in the presence of hydrogen.
Claim 14
Dependent Claim
78 words
A method according to Claim 10, wherein the platinum group metals in step (cA3) or (cB3) are provided in the form of water soluble platinum group metal compounds which are selected from the group consisting of sulfito complexes of platinum group metals, chloroplatinic acid, potassium platinum chloride, ammonium platinum thiocyanate, platinum tetrammine hydroxide, platinum group metal chlorides, oxides, sulfides, nitrites and nitrates, platinum tetrammine chloride, palladium tetrammine chloride, sodium palladium chloride, hexammine rhodium chloride, and hexammine iridium chloride.
Claim 15
Dependent Claim
39 words
A method according to Claim 10, wherein the platinum group metals in step (cA3) or (cB3) include Rh and wherein at least a part of the Rh containing solution is impregnated separately from the other platinum group metal solutions.
Claim 16
Dependent Claim
16 words
A method according to Claim 12, wherein the Rh containing solution further contains a penetration aid.
Claim 17
Dependent Claim
20 words
A method according to Claim 10, wherein nickel is further added in an amount of 0.5 to 20 wt.% NiO.
Claim 18
Dependent Claim
59 words
A method according to Claim 10, wherein the solutions of cerium salt and lithium salt are applied in step (cB1) either (a) by first a cerium salt followed by a lithium salt, (b) by first a lithium salt followed by cerium salt or (c) by a simultaneous application of a mixture of the cerium salt and the lithium salt.
Claim 19
Dependent Claim
9 words
A catalyst made by the process of Claim 10.
Claim 20
Independent Claim
275 words
A method of making a catalyst which is suitable for use as a three-way catalyst for auto emission comprising the steps of a) applying promoters and at least two platinum group metals by either A) 1) impregnating an alumina support which has been heated to at least 3000 C with a soluble cerium salt solution; 2) heating the impregnated support to at least decompose the cerium salt to obtain a ceria impregnated support; and 3) impregnating the ceria impregnated support with solutions bearing one or more platinum group metals and at least one alkali metal, and further including a Rh containing solution which has at least part of the Rh solution impregnated separately from the other platinum group metal solutions and alkali metal-bearing solutions; or B) 1) impregnating an alumina support which has been heated to at least 300°C with a solution containing a cerium salt and a lithium salt; 2) heating the impregnated support to at least decompose the cerium and lithium salts to obtain a ceria-lithia impregnated support; and 3) impregnating the ceria-lithia impregnated support with solutions bearing one or more platinum group metals including Rh and where the Rh containing solution has at least part of the Rh solution impregnated separately from the other platinum group metal solutions to form a catalyst; b) air drying the catalyst at ambient temperature for 0-4 hours, and at about 100-150°C to dry the catalyst after each impregnation with solutions bearing catalytic metals; and c) activating the catalyst, which has previously been heated to a temperature of at least 800-1100°C in step (a) at a temperature of about 250-550°C and preferably in the presence of hydrogen.
Claim 21
Independent Claim
275 words
A method of making a catalyst which is suitable for use as a three-way catalyst for auto emission comprising the steps of a) applying promoters and at least two platinum group metals by either A) 1) impregnating an alumina support which has been heated to at least 3000 C with a soluble cerium salt solution; 2) heating the impregnated support to at least decompose the cerium salt to obtain a ceria impregnated support; and 3) impregnating the ceria impregnated support with solutions bearing one or more platinum group metals and at least one alkali metal, and further including a Rh containing solution which has at least part of the Rh solution impregnated separately from the other platinum group metal solutions and alkali metal-bearing solutions; or B) 1) impregnating an alumina support which has been heated to at least 300°C with a solution containing a cerium salt and a lithium salt; 2) heating the impregnated support to at least decompose the cerium and lithium salts to obtain a ceria-lithia impregnated support; and 3) impregnating the ceria-lithia impregnated support with solutions bearing one or more platinum group metals including Rh and where the Rh containing solution has at least part of the Rh solution impregnated separately from the other platinum group metal solutions to form a catalyst; b) air drying the catalyst at ambient temperature for 0-4 hours, and at about 100-150°C to dry the catalyst after each impregnation with solutions bearing catalytic metals; and c) activating the catalyst, which has previously been heated to a temperature of at least 800-1100°C in step (a) at a temperature of about 250-550°C and preferably in the presence of hydrogen.
Claim 22
Dependent Claim
78 words
A method according to Claim 17, wherein the platinum group metals in step (aA3) or (aB3) are provided in the form of water soluble platinum group metal compounds which are selected from the group consisting of sulfito complexes of platinum group metals, chloroplatinic acid, potassium platinum chloride, ammonium platinum thiocyanate, platinum tetrammine hydroxide, platinum group metal chlorides, oxides, sulfides, nitrites and nitrates, platinum tetrammine chloride, palladium tetrammine chloride, sodium palladium chloride, hexammine rhodium chloride, and hexammine iridium chloride.
Claim 23
Dependent Claim
16 words
A method according to Claim 17, wherein the Rh containing solution further contains a penetration aid.
Claim 24
Dependent Claim
20 words
A method according to Claim 17, wherein nickel is further added in an amount of 0.5 to 20 wt.% NiO.
Claim 25
Dependent Claim
59 words
A method according to Claim 17, wherein the solutions of cerium salt and lithium salt are applied in step (aB1) either (a) by first a cerium salt followed by a lithium salt, (b) by first a lithium salt followed by cerium salt or (c) by a simultaneous application of a mixture of the cerium salt and the lithium salt.
Claim 26
Dependent Claim
9 words
A catalyst made by the process of Claim 17.
References Cited (Backward Citations)
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