Systems and Methods for Variations of ZPGM Oxidation Catalysts Compositions
The present disclosure refers to variation of compositions for catalytic converters free of platinum group metals, which may be employed to manufacture ZPGM oxidation catalyst systems, to remove main pollutants from exhaust of diesel engines, by oxidizing toxic gases. Suitable support oxides material may include ZrO 2 , ZrO 2 doped with lanthanide group metals, Nb 2 O 5 , Nb 2 O 5 —ZrO 2 , Al 2 O 3 and Al 2 O 3 doped with lanthanide group metals, TiO 2 and doped TiO 2 may be used. Materials suitable for use as ZPGM catalysts include Lanthanum (La), Yttrium (Y), Silver (Ag), Manganese (Mn) and combinations thereof. The disclosed ZPGM DOC systems may include perovskite structures with the characteristic formulation ABO 3 or related structures. A plurality of methods may be employed for production of ZPGM diesel oxidation catalyst systems substantially free of PGM, which may include a substrate, a washcoat, and an impregnation layer.
1 . A method for forming a zero platinum group metal (ZPGM) catalyst, comprising:
providing at least one substrate, wherein the at least one substrate is selected from the group consisting of cordierite, zeolite, and combinations thereof;
depositing by co-precipitation a washcoat suitable for deposition on the substrate, the washcoat comprising at least one oxide solid further comprising at least one carrier metal oxide and at least one first ZPGM catalyst; and
depositing by co-precipitation an overcoat suitable for deposition on the substrate, the overcoat comprising at least one second ZPGM catalyst;
wherein at least one of the first ZPGM catalyst and second ZPGM catalyst comprises at least one perovskite structured compound having the formula ABO 3 , wherein A and B are selected from the group consisting of at least one of lanthanum, yttrium, silver, manganese, and combinations thereof; and
wherein the at least one carrier metal oxide comprises ZrO 2 .
2 . The method of claim 1 , wherein the at least one carrier metal oxide further comprises at least one selected from the group consisting of TiO 2 , doped TiO 2 , alumina, doped alumina, doped ZrO 2 , Nb 2 O 5 —ZrO 2 , and combinations thereof.
3 . The method of claim 1 , wherein the substrate comprises at least one selected from the group consisting of metallic alloy, microporous material, and combinations thereof.
4 . The method of claim 1 , wherein the at least one perovskite structured compound is of the general formula A 1-x Ag x MnO 3 , wherein x is from 0 to 0.5 and where A is yttrium or lanthanum.
5 . The method of claim 1 , further comprising depositing by co-precipitation an impregnation layer suitable for deposition on the substrate, the impregnation layer comprising at least one third ZPGM catalyst.
6 . The method of claim 5 , wherein silver is present in the impregnantion layer by about 1% to about 10% by weight.
7 . The method of claim 1 , wherein the at least one perovskite structured compound has the formula AgBO 3 , wherein B is selected from the group consisting of at least one of lanthanum, yttrium, silver, manganese, and combinations thereof.
8 . The method of claim 1 , wherein the at least one substrate at least one metallic alloy, a foam, a microporous materials.
9 . The method of claim 1 , wherein a T50 conversion temperature for carbon monoxide is less than about 230 degrees Celsius.
10 . The method of claim 1 , wherein a T50 conversion temperature for hydrocarbons is less than about 250 degrees Celsius.
11 . The method of claim 1 , wherein the washcoat is fired at about 750° C. for about 4 hours.
12 . The method of claim 1 , wherein manganese is present in the washcoat by about 10% to about 30% by weight.
13 . The method of claim 1 , wherein yttrium is present in the washcoat by about 10% to about 40% by weight.
14 . The method of claim 1 , wherein oxidation of NO is about 43%.
15 . The method of claim 1 , wherein the oxidation of NO is at about 396° C.
16 . The method of claim 1 , where the overcoat is a slurry and is deposited in a single step.
17 . The method of claim 1 , where the washcoat is a slurry and is deposited in a single step.
18 . The method of claim 1 , wherein the NO conversion rate corresponds to the carrier material oxide.