CATALYST FOR PARTICULATE COMBUSTION IN GASOLINE EMISSION TREATMENT SYSTEMS
Disclosed herein is a catalyst for particulate combustion which is essentially free of platinum group metal compounds and the catalyst comprises a carrier and at least one metal oxide chosen from iron oxide and manganese oxide, and combinations thereof.
1 . A catalyst for particulate combustion comprising: a carrier and at least one metal oxide chosen from iron oxide, manganese oxide, and combinations thereof, wherein the catalyst is essentially free of platinum group metal compounds.
2 . The catalyst for particulate combustion according to claim 1 , wherein the catalyst comprises from 5 wt. % to 90 wt. %, from 10 wt. % to 80 wt. %, from 30 wt. % to 70 wt. %, or from 30 wt. % to 60 wt. % of the carrier, based on a calcined weight of the catalyst.
3 . The catalyst for particulate combustion according to claim 1 , wherein the catalyst comprises from 0 wt. % to 95 wt. %, from 5 wt. % to 90 wt. %, from 10 wt. % to 70 wt. %, or 10 wt. % to 50 wt. % iron oxide, based on a calcined weight of the catalyst.
4 . The catalyst for particulate combustion according to claim 1 , wherein the catalyst comprises from 0 wt. % to 90 wt. %, from 0 wt. % to 80 wt. %, from 20 wt. % to 60 wt. %, or 30 wt. % to 60 wt. % manganese oxide, based on the calcined weight of the catalyst.
5 . The catalyst for particulate combustion according to claim 1 , wherein the carrier is: one or more of materials chosen from alumina, zirconia-alumina, silica-alumina, lanthana, lanthana-alumina, silica-zirconia lanthana, alumina-zirconia-lanthana, titania, zirconia-titania, neodymia, praseodymia, ceria-zirconia, ceria-alumina, baria-ceria-alumina and ceria; or one or more of materials chosen from alumina, zirconia-alumina, ceria, alumina, zirconia-alumina; and alumina.
6 . The catalyst for particulate combustion according to claim 1 , wherein the catalyst comprises from 10 wt. % to 50 wt. % iron oxide, from 30 wt. % to 60 wt. % carrier, and from 20 wt. % to 60 wt. % manganese oxide, based on a calcined weight of the catalyst.
7 . The catalyst for particulate combustion according to claim 1 , prepared by a process comprising:
providing a washcoat slurry via impregnating a surface of the carrier with particles comprising iron oxide and/or manganese oxide, optionally diluting and/or mixing with one or more other components;
coating pores and/or a surface of a porous internal walls of a gasoline particulate filter (GFP) with the washcoat slurry to obtain a coated GFP and optionally drying the coated GPF under a temperature ranging from 100° C. to 150° C.; and
calcinating the coated GPF at a temperature ranging from 300° C. to 500° C., or 350° C. to 450° C.
8 . The catalyst for particulate combustion according to claim 1 , prepared by a process comprising:
providing a mixture of the carrier and particles comprising iron oxide and/or manganese oxide using a slurry process, optionally mixing with one or more other components; and dry coating channels and/or pores of a porous internal wall of a gasoline particulate filter (GPF) with the provided mixture to obtain a coated GFP.
9 . The catalyst for particulate combustion according to claim 1 , prepared by a process comprising:
providing a washcoat slurry via impregnating the surface of the carrier with particles comprising iron oxide and/or manganese oxide, optionally diluting and/or mixing with one or more other components;
coating pores and/or a surface of a porous internal wall of a gasoline particulate filter (GPF) with the provided washcoat slurry to obtain a coated GFP and optionally drying the coated GPF under a temperature ranging from 100° C. to 150° C.;
calcinating the coated GPF under a temperature ranging from 30 0° C. to 500° C., or 350° C. to 450° C. to obtain a calcined GFP;
providing a mixture of the carrier and particles comprising iron oxide and/or manganese oxide using a slurry process, optionally mixing with one or more other components; and
dry coating channels and/or pores of a porous internal walls of the calcined GPF with the provided mixture, optionally wherein the dry coating is coated in the inlet of the calcined GPF.
10 . The catalyst for particulate combustion according to claim 1 , wherein the D90 of the particles comprising iron oxide and/or manganese oxide ranges from 2 μm to 20 μm, 2 μm to 18 μm, 3 μm to 15 μm, or 5 μm to 13 μm.
11 . The catalyst for particulate combustion according to claim 7 , wherein the GPF comprises an inlet end, an outlet end, a substrate axial length extending between the inlet end and the outlet end, and a plurality of passages defined by porous internal walls of the porous wall flow filter substrate, wherein the plurality of passages comprise inlet passages having an open inlet end and a closed outlet end, and outlet passages having a closed inlet end and an open outlet end.
12 . The catalyst for particulate combustion according to claim 7 , wherein the carrier is: one or more of materials chosen from alumina, zirconia-alumina, silica-alumina, lanthana, lanthana-alumina, silica-zirconia lanthana, alumina-zirconia-lanthana, titania, zirconia-titania, neodymia, praseodymia, ceria-zirconia, ceria-alumina, baria-ceria-alumina and ceria; or one or more of materials chosen from alumina, zirconia-alumina, ceria, alumina, zirconia-alumina; and alumina.
13 . The catalyst for particulate combustion according to claim 1 , wherein the carrier has a surface area ranging from 50 m 2 /g to 500 m 2 /g, 100 m 2 /g to 400 m 2 /g, or 100 m 2 /g to 200 m 2 /g.
14 . A particulate filter for filtering out particulate present in the exhaust gases of an internal combustion engine, wherein the particulate filter comprises a catalyst according to claim 1 .
15 . The particulate filter according to claim 14 , wherein the catalyst according to claim 1 is coated at the inlet channels of the particulate filter.
16 . The particulate filter according to claim 14 , wherein the catalyst is coated onto the particulate filter along the whole of its axial length, part of its axial length, the whole of its radial direction, part of its radial direction, alternating channels, on a wall, in a porous wall, or a combination thereof.
17 . The particulate filter according to claim 14 , wherein the particulate filter comprises a wall-flow filter comprising a honeycomb structure.
18 . The particulate filter according to claim 14 , wherein the mean pore size of the particulate filter ranges from 10 μm to 24 μm, or from 14 μm to 20 μm.
19 . The particulate filter according to claim 14 , wherein the porosity of the particulate filter ranges from 40% to 65%.
20 . A gasoline engine exhaust gas purification system, wherein the exhaust gas purification system comprises the particulate filter according to claim 14 , and at least one TWC, wherein optionally, the TWC is upstream of the particulate filter.
21 . The gasoline engine exhaust gas purification system according to claim 20 , wherein the TWC comprises palladium, rhodium, and optionally platinum.