EP0444470A1
Expired / Lapsed
EP
⏱️ 0.0 years remaining
High surface area ceria
Assignee: WR Grace and Co Conn
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Filing: 1991-02-13
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Granted: —
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Expires: 2011-02-13
Abstract
Abstract A thermally stable, high surface area ceria composition is obtained by intimately adding a ceria stabilizer of one or more of La, Nd or Y to the ceria in an amount of from about 5 to 25 mole % of the ceria. One way to make the product is to mix the stabilizer with a ceria precursor such as cerium nitrate, evaporate the mixture and then calcine the salts to form the stabilized ceria. Another way to make the product is to form an aqueous solution of precursor salts which are precipitated with a base to form hydrous cerous and stabilizer hydroxides or their carbonates. This mixture can be washed and then calcined to form the stabilized ceria. After heating in air for 4 hours at 900°C the stabilized ceria retains a surface area of greater than 20 m² /g.
Inventors
- 👤 Nicole Elise Ashley
- 👤 Jeffery Scott Rieck
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-24 21:26
CPC Classifications
B; B01; B01J; B01J37/00; B01J37/02; B01J37/03; B01J23/00; B01J23/10; C; C01; C01F; C01F17/00; C01F17/20; C01F17/206; C01F17/224; C01F17/235; C01F17/241; C01F17/247; B01J35/00; B01J35/60; B01J35/61; B01J35/613; C01P; C01P2006/00; C01P2006/12; C01P2006/13
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
40 words
A thermally stable, high surface area ceria composition comprising ceria and from about 5 to 25 mole % based on the moles of ceria of a ceria stabilizer selected from the group consisting of La, Nd, Y and mixtures thereof.
Claim 2
Dependent Claim
35 words
A ceria composition according to Claim 1, wherein after heating the composition to a temperature of 980°C for four hours in air, the composition retains a BET surface area of greater than 20 m² /g.
Claim 3
Dependent Claim
26 words
A ceria composition according to Claim 1, wherein the ceria stabilizer is present from about 5 to 20 mole % based on the moles of ceria.
Claim 4
Dependent Claim
23 words
A ceria composition according to Claim 3, wherein the ceria stabilizer is present in about 10% mole based on the moles of ceria.
Claim 5
Dependent Claim
13 words
A ceria composition according to Claim 1, wherein the ceria stabilizer is La.
Claim 6
Dependent Claim
13 words
A ceria composition according to Claim 1, wherein the ceria stabilizer is Nd.
Claim 7
Dependent Claim
13 words
A ceria composition according to Claim 1, wherein the ceria stabilizer is Y.
Claim 8
Independent Claim
89 words
A method of producing thermally stable, high surface area ceria composition comprising the steps: (a) mixing a ceria precursor with from 5 to 25 mole % of a ceria stabilizer selected from the group consisting of La, Nd, Y and mixtures thereof; (b) forming an intimate mixture of the ceria precursor and the ceria stabilizer by either evaporation of the mixture of step (a) or precipitation of the mixture of step (a) as a hydroxide or a carbonate; and (c) calcining the resulting intimate mixture to obtain stabilized ceria.
Claim 9
Dependent Claim
24 words
A method according to Claim 8, wherein the ceria stabilizer is added in step (a) in the form of a ceria stabilizer precursor compound.
Claim 10
Dependent Claim
30 words
A method according to Claim 9, wherein the ceria stabilizer precursor is a salt selected from the group consisting of acetate, bromate, bromide, chloride, iodide, nitrate, sulfate, and mixtures thereof.
Claim 11
Dependent Claim
20 words
A method according to Claim 8, wherein in step (b) the intimate mixture is formed by evaporation of the mixture.
Claim 12
Dependent Claim
30 words
A method according to Claim 8, wherein in step (b) the intimate mixture is formed by precipitation of the ceria and ceria stabilizer from precursor compounds as hydroxides or carbonates.
Claim 13
Dependent Claim
27 words
A method according to Claim 12, wherein the precipitation as hydroxides is performed by adding a solution of ammonium hydroxide, caustic soda, or other alkali metal hydroxides.
Claim 14
Dependent Claim
27 words
A method according to Claim 12, wherein the precipitation as carbonate is performed by adding a solution of ammonium carbonate, sodium carbonate, or other alkali metal carbonates.
Claim 15
Dependent Claim
17 words
A method according to Claim 12, wherein the precipitate is filtered and washed free of other salts.
Claim 16
Dependent Claim
20 words
A method according to Claim 15, wherein the washing is done with water, ammonia in water, methanol or other solvents.
Claim 17
Dependent Claim
25 words
A method according to Claim 8, wherein the ceria stabilizer is present from about 5 to 20 mole % based on the moles of ceria.
Claim 18
Dependent Claim
23 words
A method according to Claim 17, wherein the ceria stabilizer is present in about 10 mole % based on the moles of ceria.
Claim 19
Dependent Claim
46 words
A method according to Claim 8, wherein the ceria precursor is selected from the group consisting of cerous acetate, cerous bromide, cerous chloride, cerous iodide, cerous nitrate, cerous sulfate, ceric sulfate, ammonium cerous sulfate, ammonium cerous nitrate, ammonium ceric sulfate, ammonium ceric nitrate, and mixtures thereof.
References Cited (Backward Citations)
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