Catalyst for purifying exhaust gas and process for producing the same
First Claim
Patent Images
1. A process for producing a catalyst for purifying an exhaust gas, comprising the steps of:
- preparing a suspension by dispersing a precursor powder in a solvent, the precursor powder including amorphous and homogeneous composite particles, and a catalytic noble metal element, the composite particles including a support component, and an NOx storage component, the support component including an oxide of metal being at least one element selected from the group consisting of group 3B elements, group 4A elements and group 4B elements in the periodic table of the elements, the NOx storage component including at least one element selected from the group consisting of alkali metals, alkaline-earth metals and rare-earth elements, the catalytic noble metal element being only in a state in which the catalytic noble metal element is involved homogeneously in the composite particles, the solvent being free from elution of the NOx storage component, preparing a slurry by mixing an organosol with the suspension, the organosol including an organic solvent, and an oxide sol including at least one oxide selected from the group consisting of oxides of aluminum (Al), oxides of silicon (Si) and oxides of zirconium (Zr), and dispersed in the organic solvent; and
depositing the slurry on a support substrate, and drying and thermally treating the support substrate, thereby forming a coating layer on the support substrate.
1 Assignment
0 Petitions
Accused Products
Abstract
A catalyst for purifying an exhaust gas includes amorphous and homogeneous composite oxide particles, a catalytic noble metal element, and metallic oxide particles. The metallic oxide particles interpose among the composite oxide particles to connect them with each other at least. The catalyst has good heat resistance, sulfur-poisoning resistance, and durability. The catalyst is produced as follows. A slurry is prepared by mixing an organosol with a suspension, or by mixing a solution with a suspension. The slurry is deposited on a support substrate to form a coating layer thereon. The suspension includes a precursor powder, and a solvent. The precursor powder includes the composite oxide particles, and the catalytic noble metal element. The composite oxide particles include a support component, and an NOx storage element. The solvent is free from elution of the NOx storage element. The organosol includes an organic solvent, and an oxide sol. The solution includes an organic solvent, and an organometallic compound. The oxide sol and organometallic compound includes aluminum, silicon or zirconium.
-
Citations
12 Claims
-
1. A process for producing a catalyst for purifying an exhaust gas, comprising the steps of:
-
preparing a suspension by dispersing a precursor powder in a solvent, the precursor powder including amorphous and homogeneous composite particles, and a catalytic noble metal element, the composite particles including a support component, and an NOx storage component, the support component including an oxide of metal being at least one element selected from the group consisting of group 3B elements, group 4A elements and group 4B elements in the periodic table of the elements, the NOx storage component including at least one element selected from the group consisting of alkali metals, alkaline-earth metals and rare-earth elements, the catalytic noble metal element being only in a state in which the catalytic noble metal element is involved homogeneously in the composite particles, the solvent being free from elution of the NOx storage component, preparing a slurry by mixing an organosol with the suspension, the organosol including an organic solvent, and an oxide sol including at least one oxide selected from the group consisting of oxides of aluminum (Al), oxides of silicon (Si) and oxides of zirconium (Zr), and dispersed in the organic solvent; and
depositing the slurry on a support substrate, and drying and thermally treating the support substrate, thereby forming a coating layer on the support substrate. - View Dependent Claims (2, 3, 4, 5, 6, 7)
preparing a first solution with a sol which includes an oxide constituting the support component;
mixing the first solution with a second solution of a compound which includes said NOx storage component;
turning the mixed solution into a gel; and
thermally treating the resulting gel.
-
-
3. The process according to claim 1 further comprising a step of preparing the composite particles, wherein said step is carried out by a sol-gel process by supplying both of the support component and the NOx storage component as their metallic alkoxides.
-
4. The process according to claim 1, wherein, in said step of preparing a slurry, a concentration of the precursor powder falls in a range of from 30 to 70% in the slurry.
-
5. The process according to claim 1, wherein, in said step of preparing a slurry, the organosol is added to the suspension in such an amount that the element constituting the organosol occupies in a range of from 0.1 to 20% by weight in the resulting coating layer formed on the support substrate, the range expressed by an amount of oxide of the element therein.
-
6. The process according to claim 1, wherein said step of preparing a slurry includes a step of selecting at least one organosol from the group consisting of an organoalumina sol, an organosilica sol an organozirconia sol.
-
7. The process according to claim 1, wherein said step of preparing a slurry includes a step of selecting the organosol having an average particle diameter of 100 nm or less.
-
8. A process for producing a catalyst for purifying an exhaust gas, comprising the steps of:
-
preparing a suspension by dispersing a precursor powder in a solvent, the precursor powder including amorphous and homogeneous composite particles, the composite particles including a support component, an NOx storage component and a catalytic noble metal element, the support component including an oxide of metal being at least one element selected from the group consisting of group 3B elements, group 4A elements and group 4B elements in the periodic table of the elements, the NOx storage component including at least one element selected from the group consisting of alkali metals and alkaline-earth metals, the catalytic noble metal element being only in a state in which the catalytic noble metal element is involved homogeneously in the composite particles, the solvent being free from elution of the NOx storage component, preparing a slurry by mixing an organosol with the suspension, the organosol including an organic solvent, and an oxide sol including at least one oxide selected from the group consisting of oxides of aluminum (Al), oxides of silicon (Si) and oxides of zirconium (Zr), and dispersed in the organic solvent; and
depositing the slurry on a support substrate, and drying and thermally treating the support substrate, thereby forming a coating layer on the support substrate. - View Dependent Claims (9, 10, 11, 12)
-
Specification
-
- Resources
Litigation Campaign Assessment
Thank you for your request. You will receive a custom alert email when the Litigation Campaign Assessment is available.
×
-
Current AssigneeToyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
-
Original AssigneeToyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
-
InventorsTsuji, Shinji
-
Primary Examiner(s)Langel, Wayne
-
Assistant Examiner(s)Nguyen, Cam N.
-
Application NumberUS08/791,162Time in Patent Office1,608 DaysField of Search423/235, 423/213.5, 502/303, 502/304, 502/242, 502/243, 502/250, 502/251, 502/252, 502/258, 502/261, 502/262, 502/325, 502/328, 502/330, 502/332, 502/333, 502/334, 502/339, 502/344, 502/347, 502/348US Class Current502/242CPC Class CodesB01D 2255/91 NOx-storage component incor...B01D 53/945 characterised by a specific...B01J 23/58 with alkali- or alkaline ea...B01J 23/63 with rare earths or actinidesB01J 37/0219 the coating containing orga...Y02T 10/12 Improving ICE efficiencies
