Preparation of supported metal nanoparticles using polyamine for three-way catalysis application
A method of manufacturing a catalyst article, the method comprising: providing a complex of a polyamine and a PGM; providing a support material; applying the complex to the support material to form a loaded support material; disposing the loaded support material on a substrate; and heating the loaded support material to form nanoparticles of the PGM on the support material.
1. A method of manufacturing a catalyst article, the method comprising:
providing a complex of a polyamine and a PGM;
providing a support material;
applying the complex to the support material to form a loaded support material;
disposing the loaded support material on a substrate; and
heating the loaded support material to form nanoparticles of the PGM on the support material;
wherein the complex has a PGM to amino group ratio of from 1:5 to 1:7.
2. The method of claim 1 , wherein the polyamine comprises polyethyleneimine.
3. The method of claim 1 , wherein the polyamine has a weight average molecular weight Mw of from 100 to 1,000,000 g/mol.
4. The method of claim 1 , wherein the PGM is selected from one or more of rhodium, palladium and platinum.
5. The method of claim 1 , wherein the support material comprises an oxide, preferably one of more of Al 2 O 3 , SiO 2 , TiO 2 , CeO 2 , ZrO 2 , CeO 2 —ZrO 2 , V 2 O 5 , La 2 O 3 and zeolites.
6. The method of claim 5 , wherein the alumina and/or ceria-zirconia is doped.
7. The method of claim 6 , wherein the alumina and/or ceria-zirconia is doped with an oxide of one or more of lanthanum, neodymium, yttrium, niobium, praseodymium, hafnium, molybdenum, titanium, vanadium, zinc, cadmium, manganese, iron, copper, calcium, barium, strontium, caesium, magnesium, potassium and sodium, preferably one or more of lanthanum, neodymium and yttrium.
8. The method of claim 6 , wherein the dopant is present in the alumina and/or ceria-zirconia in an amount of from 0.001 wt. % to 20 wt. %.
9. The method of claim 1 , wherein the loaded support material is disposed on the substrate in the form of a slurry.
10. The method of claim 9 , wherein the slurry is prepared by a method comprising:
contacting a PGM salt and a polyamine in water to form the complex of a polyamine and a PGM in an aqueous solution;
applying the complex to the support material to form a loaded support material by contacting the support material with the aqueous solution.
11. The method of claim 9 , wherein the PGM comprises rhodium and the support material comprises alumina and ceria-zirconia.
12. The method of claim 9 , wherein disposing the loaded support material on a substrate comprises contacting the slurry with the substrate, applying a vacuum to the substrate, and/or drying the slurry on the substrate.
13. The method of claim 12 , wherein the drying occurs at a temperature of from 60° C. to 200° C.
14. The method of claim 1 , wherein the substrate is in the form of a honeycomb monolith, a wall flow filter or a flow through filter.
15. The method of claim 1 , wherein the heating is carried out:
at a temperature of from 400° C. to 700° C.; and/or
for from 10 to 360 minutes.
16. A catalyst article obtainable by the method of claim 1 , the catalyst article for use in an emission treatment system.
17. The catalyst article of claim 16 comprises a bottom layer of support material having rhodium thereon and a top layer of support material having palladium thereon.
18. The catalyst article of claim 16 comprising a bottom layer of support material having palladium thereon and a top layer of support material having rhodium thereon.
19. The catalyst article of claim 17 comprising from 2 g/ft 3 to 15 g/ft 3 rhodium.
20. The catalyst article of claim 17 comprising from 50 g/ft 3 to 200 g/ft 3 palladium.
21. An emission treatment system comprising the catalyst article of claim 16 .
22. The emission treatment system of claim 21 for a gasoline engine.