COATINGS ON A MONOLITH ARTICLE
The present disclosure relates to a coated monolith article for filtering particulate matter from exhaust gases. The monolith article has an inlet end and an outlet end, and comprises a coating. The article comprises an inorganic oxide applied to the inlet end of the article and a washcoat coating applied to the outlet end of the article. The present disclosure also relates to a method of forming the coated monolith article as described herein and an exhaust system with a coated monolith article as described herein.
1 . A monolith article comprising an inlet end and an outlet end, and a coating, said coating comprising:
a) an inorganic oxide coating applied to the inlet end of the article, and
b) a washcoat coating applied to the outlet end of the article.
2 . The monolith article according to claim 1 , wherein the monolith article is a monolith filter.
3 . The monolith article according to claim 1 , wherein the inorganic oxide coating comprises inorganic particles, and a silicone resin, wherein the inorganic particles comprise an aluminosilicate zeolite selected from the group comprising AEI, BEA, CHA, FAU and MFI, and/or
wherein the total inorganic oxide coating is present in a mass loading of between 1-25 g/L.
4 . The monolith article according to claim 3 , wherein the ratio of inorganic particles to silicone resin in the inorganic oxide coating is from 0.5:1 to 5:1.
5 . The monolith article according to claim 1 , wherein the washcoat coating comprises ceria zirconia, alumina, precious metals selected from Pd, Pt or Rh, barium hydroxide, a rheology modifier and a C 2 -C 6 aliphatic amino acid (e.g. 3-amino-propionic acid), and/or wherein the total washcoat loading is from 65 to 85 g/L.
6 . A method of forming a coated monolith article, said method comprising:
i) providing a monolith article which has an inlet end and an outlet end,
ii) applying an inorganic oxide coating to the inlet end,
iii) optionally drying and/or calcining the inorganic coating,
iv) applying a washcoat coating to the outlet end,
v) optionally drying and/or calcining the resulting article.
7 . A method of claim 6 , wherein the washcoat coating is applied such that it extends from 60-100% of the length of the article from the outlet end, preferably from 65-95%, e.g., from 70-90% or 75-80% of the length of the article from the outlet end.
8 . The method of claim 6 , wherein the washcoat loading is applied to the monolith article at the outlet end of the monolith article in a single dose or in multiple doses.
9 . The method of claim 6 , wherein a mixture of inorganic particles and silicone resin is sprayed as a dry particulate aerosol to from the inorganic oxide coating.
10 . The method of claim 6 , wherein the inorganic oxide coating comprises inorganic particles and a silicone resin, wherein the inorganic particles comprise an aluminosilicate zeolite selected from the group comprising AEI, BEA, CHA, FAU and MFI.
11 . The method of claim 6 , wherein the silicone resin has a molecular weight of greater than 1,000.
12 . The method of claim 6 , wherein the silicon resin has the formula [R x SiX y O z ] n , wherein R is an alkyl or aryl, X is a functional group bonded to silicon and z is more than 1 and less than 2, and y is less than 1.
13 . The method of claim 6 , wherein the silicone resin has a degree of crosslinking of greater than 55%, preferably greater than 60%, more preferably greater than 65%, and/or a degree of crosslinking of less than 85%, preferably less than 80%.
14 . An exhaust gas system comprising the coated monolith article of claim 1 , and optionally, a combustion engine.
15 . A method for the treatment of an exhaust gas, the method comprising contacting the exhaust gas with the coated monolith article of claim 1 .