Method for manufacturing gasoline particulate filter
A method for the manufacture of a gasoline particulate filter (GPF) for the treatment of an exhaust gas is disclosed. The method comprises (i) forming a washcoat slurry; (ii) coating a wall-flow filter substrate with the washcoat slurry to form a washcoated substrate; and (iii) calcining the washcoated substrate to form a gasoline particulate filter. The washcoat slurry comprises (a) a platinum group metal selected from the group consisting of Pt, Pd, Rh and mixtures thereof; (b) an oxygen storage capacity (OSC) material; and (c) a C 2 -C 6 aliphatic amino acid.
1 . A method for the manufacture of a gasoline particulate filter (GPF) for the treatment of an exhaust gas, the method comprising:
(i) forming a washcoat slurry;
(ii) coating a wall-flow filter substrate with the washcoat slurry to form a washcoated substrate; and
(iii) calcining the washcoated substrate to form a gasoline particulate filter;
wherein the washcoat slurry comprises (a) a platinum group metal selected from the group consisting of Pt, Pd, Rh and mixtures thereof; (b) an oxygen storage capacity (OSC) material; and (c) a C 2 -C 6 aliphatic amino acid.
2 . The method of claim 1 , wherein the C 2 -C 6 aliphatic amino acid has the formula HO 2 C—(CH 2 ) n —NH 2 , wherein n is from 1 to 5.
3 . The method of claim 2 , wherein n is from 1 to 3.
4 . The method of claim 2 , wherein n is 2.
5 . The method of claim 4 , wherein the amount of the C 2 -C 6 aliphatic amino acid in the 30 washcoat slurry is from 1 to 50% wt % relative to the crucible solids in the washcoat slurry.
6 . The method of claim 4 , wherein the amount of the C 2 -C 6 aliphatic amino acid in the washcoat slurry is from 2 to 40 wt % relative to the crucible solids in the washcoat slurry.
7 . The method of claim 4 , wherein the amount of the C 2 -C 6 aliphatic amino acid in the washcoat slurry is from 5 to 30 wt % relative to the crucible solids in the washcoat slurry.
8 . The method of claim 4 ,
wherein the amount of the C 2 -C 6 aliphatic amino acid in the washcoat slurry is from 5 to 30 wt % relative to the crucible solids in the washcoat slurry;
wherein the OSC material comprises a cerium-zirconium mixed oxide nano sol with a mean particle size of less than 1 μm; and
wherein the inorganic oxide support is a gamma-alumina having a mean particle size of from 1 to 10 μm.
9 . The method of claim 4 ,
wherein the amount of the C 2 -C 6 aliphatic amino acid in the washcoat slurry is from 5 to 30 wt % relative to the crucible solids in the washcoat slurry;
wherein the OSC material comprises a cerium-zirconium mixed oxide nano sol with a mean particle size of less than 1 μm;
wherein the inorganic oxide support is a gamma-alumina having a mean particle size of from 2 to 8 μm.
10 . The method of claim 4 ,
wherein the amount of the C 2 -C 6 aliphatic amino acid in the washcoat slurry is from 5 to 30 wt % relative to the crucible solids in the washcoat slurry;
wherein the OSC material comprises a cerium-zirconium mixed oxide with a mean particle size of from 5 to 10 μm; and
wherein the inorganic oxide support is a nano alumina with a mean particle size of less than 1 μm.
11 . The method of claim 1 , wherein the amount of the C 2 -C 6 aliphatic amino acid in the washcoat slurry is from 1 to 50% wt % relative to the crucible solids in the washcoat slurry.
12 . The method of claim 1 , wherein the amount of the C 2 -C 6 aliphatic amino acid in the washcoat slurry is from 2 to 40 wt % relative to the crucible solids in the washcoat slurry.
13 . The method of claim 1 , wherein the amount of the C 2 -C 6 aliphatic amino acid in the washcoat slurry is from 5 to 30 wt % relative to the crucible solids in the washcoat slurry.
14 . The method of claim 1 , wherein the washcoat slurry comprises Pt and Rh.
15 . The method of claim 1 , wherein the washcoat slurry comprises Pd and Rh.
16 . The method of claim 1 , wherein the OSC material comprises a mixed oxide of cerium and zirconium; a mixed oxide of cerium, zirconium, and aluminium; a mixed oxide of cerium, zirconium, and neodymium; or a mixed oxide of cerium, zirconium and praseodymium.
17 . The method of claim 1 , wherein the OSC material comprises a cerium-zirconium mixed oxide nano sol with a mean particle size of less than 1 μm.
18 . The method of claim 1 , wherein the washcoat slurry further comprises an inorganic oxide support.
19 . The method of claim 18 , wherein the inorganic oxide support comprises alumina.
20 . The method of claim 18 , wherein the inorganic oxide support comprises a gamma-alumina.