Porous catalyst washcoats
Catalyst washcoats with improved porosity and methods for making the washcoats are provided. The process comprises incorporation of an oil-in-water macroemulsion into the catalyst slurry prior to washcoating the carrier substrate, and calcining the washcoated carrier substrate to remove the oil-in-water macroemulsion. Also provided are catalyst articles comprising the washcoat and methods for abatement of exhaust gas emissions.
1. A catalyst article comprising a catalyst washcoat on a carrier substrate, wherein about 30%-100% of pores within the catalyst washcoat are about 15 μm-100 μm in size in at least one dimension.
2. The catalyst article of claim 1 , wherein about 70%-100% of the pores within the catalyst washcoat are about 15 μm-100 μm in size in at least one dimension.
3. The catalyst article of claim 1 , wherein about 70%-100% of the pores within the catalyst washcoat are about 15 μm-50 μm in size in at least one dimension.
4. The catalyst article of claim 1 , wherein the carrier substrate is cordierite or metal.
5. The catalyst article of claim 1 , wherein the catalyst washcoat comprises a precious group metal catalyst and/or a base metal catalyst.
6. The catalyst article of claim 5 , wherein the precious group metal catalyst and/or base metal catalyst is impregnated on a support material.
7. A system for abatement of exhaust gas emissions comprising a source of exhaust gases in fluid flow communication with a catalyst article according to claim 1 , and at least one of a soot filter, a catalyzed soot filter and a second catalyst article in fluid flow communication with the catalyst article.
8. The system of claim 7 , wherein the carrier substrate is a ceramic or metal honeycomb substrate.
9. The system of claim 8 , wherein the carrier substrate is a flow-through monolithic substrate or a wall flow substrate.