NOx adsorbent DOC (NA-DOC) catalyst

Abstract

The present invention relates to a NOx adsorbent diesel oxidation catalyst for treating exhaust gases, the catalyst comprising: a substrate having an inlet end, an outlet end, a substrate axial length extending from the inlet end to the outlet end, and a plurality of passages defined by an interior wall of the substrate extending therethrough; a first NOx adsorbent (NA) coating comprising palladium supported on a first non-zeolitic oxide material comprising ceria; a second NOx adsorbent (NA) coating comprising one or more of an alkaline earth metal supported on a support material and a platinum group metal component supported on a second non-zeolitic oxide material; and a diesel oxidation catalyst (DOC) coating comprising a platinum group metal component supported on a third non-zeolitic oxide material.

Description

[Technical field]

[0001] The present invention relates to a NOx adsorber diesel oxidation catalyst, a process for preparing said catalyst, and the use of said catalyst.Furthermore, the present invention relates to an exhaust gas treatment system comprising said catalyst. [Background technology]

[0002] In the automotive industry, there is a constant need to reduce NOx emissions from engines as these emissions are harmful to humans. It is therefore important to address current legislation that sets limits on NOx emissions. Therefore, NOx adsorber diesel oxidation catalysts are used in conjunction with selective catalytic reduction catalysts.

[0003] Lean NOx traps (LNTs) adsorb NOx during engine cold start to minimize emissions before the downstream selective catalytic reduction (SCR) catalyst reaches light-off temperature. Regeneration of the LNT is typically performed by temporarily switching to rich exhaust gas conditions, and the adsorbed NOx is reduced to N2 on the LNT. According to the latest technology, ceria or barium based materials are used and adsorption occurs via NO2. Typically, NOx adsorption capacity and NOx desorption temperature are high for LNTs.

[0004] WO 2016 / 141142 (A1) discloses a lean NOx trap comprising barium and ceria. WO 2020 / 236879 (A1) discloses an emission treatment system for the oxidation of hydrocarbons and carbon monoxide and for the reduction of NOx in the exhaust gas of a lean-burn engine, the system comprising a low-temperature NOx sorbent comprising a molecular sieve impregnated with a platinum group metal used in combination with a diesel oxidation catalyst comprising a manganese-containing support material. However, there is still a need to provide a new NOx adsorber diesel oxidation catalyst (NA-DOC) for the treatment of exhaust gases, which exhibits improved performance, particularly with respect to its NOx adsorption and / or desorption properties at low temperatures, good thermal lean desulfation behavior and / or high stability against repeated lean / rich desulfation. Summary of the Invention

[0005] It is therefore an object of the present invention to provide a NOx adsorbent diesel oxidation catalyst (NA-DOC) for treating exhaust gases, which catalyst exhibits improved performance, in particular at low temperatures, in particular with regard to its NOx adsorption and / or desorption properties, and also offers the possibility of lean or lean / rich desulfation.

[0006] Surprisingly, it has been found that the NOx adsorber diesel oxidation catalyst according to the invention makes it possible to maintain high and durable NOx adsorption / desorption even at low temperatures and to prevent irreversible damage from sulfation / desulfation.

[0007] Accordingly, the present invention provides a NOx adsorber diesel oxidation catalyst (NA-DOC) for treating exhaust gas, comprising: (i) a substrate comprising an inlet end, an outlet end, a substrate axial length extending from the inlet end to the outlet end, and a plurality of passages defined by an interior wall of the substrate extending therethrough; (ii) a first NOx adsorber (NA) coating comprising palladium supported on a first non-zeolitic oxide material comprising ceria; and (iii) a second NOx sorbent (NA) coating comprising one or more of an alkaline earth metal supported on a support material and a platinum group metal component supported on a second non-zeolitic oxide material; and (iv) a diesel oxidation catalyst (DOC) coating, the DOC coating comprising a platinum group metal component supported on a third non-zeolitic oxide material; a first NA coating (ii) is disposed on a surface of an inner wall of the substrate (i) over x% of the substrate axial length from the exit end towards the entrance end of the substrate, where x is in the range of 20 to 70; a second NA coating (iii) disposed over y % of the substrate axial length from the inlet end towards the outlet end, y being in the range of 20 to 70; The present invention relates to a NOx adsorber diesel oxidation catalyst, wherein a DOC coating is disposed on the first NA coating and the second NA coating, or on the first NA coating, the second NA coating, and the surface of the inner wall of the substrate, over z% of the axial length of the substrate, and z is in the range of 50 to 100.

[0008] Preferably, x is in the range of 30 to 65, more preferably in the range of 35 to 60, more preferably in the range of 40 to 55, and more preferably in the range of 45 to 55.

[0009] Preferably, y is in the range of 30 to 65, more preferably in the range of 35 to 60, more preferably in the range of 40 to 55, and more preferably in the range of 45 to 55. More preferably, x is in the range of 45 to 55, and y is in the range of 45 to 55.

[0010] Preferably, y is 100-x, and more preferably, x is in the range of 45-55.

[0011] Preferably, z is in the range of 70 to 100, more preferably in the range of 80 to 100, more preferably in the range of 90 to 100, more preferably in the range of 95 to 100, more preferably in the range of 98 to 100, and more preferably in the range of 99 to 100.

[0012] Preferably 95-100% by weight, more preferably 98-100% by weight, more preferably 99-100% by weight, more preferably 99.5-100% by weight, more preferably 99.9-100% by weight of the first non-zeolitic oxide material contained in the first NA coating (ii) consists of ceria calculated as CeO2. In other words, the first non-zeolitic oxide material contained in the first NA coating (ii) preferably consists essentially of ceria calculated as CeO2, more preferably consists of ceria.

[0013] Preferably, the first NA coating has a Pd content of 5 to 150 g / ft 3 More preferably, it is in the range of 10 to 120 g / ft 3 More preferably, it is in the range of 30 to 100 g / ft 3 More preferably, it is in the range of 40 to 80 g / ft 3 More preferably, the range is 45 to 75 g / ft 3 The palladium loading ranges from 0.1 to 1.0.

[0014] Preferably, the first NA coating (ii) has a coating density of 1 to 6 g / in 3 More preferably, in the range of 2 to 5 g / in 3 More preferably, the range is 2.5 to 4.5 g / in 3 The present invention includes a loading of the first non-zeolitic oxide material in the range of

[0015] Preferably, at most 0.01 wt.-%, more preferably at most 0.001 wt.-%, more preferably at most 0.0001 wt.-%, of the first NA coating consists of barium, calculated as BaO. In other words, the first NA coating (ii) is preferably essentially free of barium, calculated as BaO, more preferably free of barium.

[0016] Preferably, at most 0.01 wt. %, more preferably at most 0.001 wt. %, more preferably at most 0.0001 wt. % of the first NA coating consists of molecular sieves. In other words, the first NA coating (ii) is preferably essentially free of molecular sieves, more preferably free of molecular sieves.

[0017] Preferably 95-100% by weight, more preferably 98-100% by weight, more preferably 99-100% by weight, more preferably 99.5-100% by weight, more preferably 99.9-100% by weight of the first NA coating (ii) consists of palladium on a first non-zeolitic oxide material, preferably palladium on ceria. In other words, the first NA coating (ii) preferably consists essentially of, more preferably consists of, palladium on a first non-zeolitic oxide material, preferably palladium on ceria.

[0018] In the context of the present invention, the first NA coating (iii) has been found by the inventors to prevent irreversible damage from sulfation / desulfation and function as a lean NOx trap.

[0019] In the context of the present invention, the catalyst comprises a second NA coating (iii) in an amount of 1.5 to 8 g / in 3 More preferably, the range is 2 to 7 g / in 3 More preferably, the range is 3 to 6.5 g / in 3 More preferably, the range is 3.5 to 5.5 g / in 3 It is preferable that the amount of the supported metal is in the range of 1.

[0020] Preferably, the second NA coating (iii) comprises a platinum group metal component which is one or more of Pt, Pd, Rh, Ir, Ru and Os, more preferably one or more of Pt, Pd and Rh, more preferably one or more of Pt and Pd, more preferably Pt and Pd.

[0021] Preferably, the weight ratio of platinum to palladium, calculated as Pt:Pd, is in the range of 5:1 to 15:1, more preferably in the range of 7:1 to 12:1, more preferably in the range of 8:1 to 10:1.

[0022] Preferably, the second NA coating (iii) has a coating weight of 5 to 150 g / ft, calculated as platinum group metal elements. 3 More preferably, it is in the range of 10 to 120 g / ft 3 More preferably, it is in the range of 30 to 100 g / ft 3 More preferably, it is in the range of 40 to 80 g / ft 3 More preferably, the range is 45 to 75 g / ft 3 The platinum group metal component comprises a loading in the range of

[0023] In the second NA coating (iii), the second non-zeolitic oxide material supporting the platinum group metal component is selected from the group consisting of ceria, alumina, zirconia, silica, titania, mixed oxides comprising one or more of Ce, Al, Zr, Si, and Ti, and mixtures of two or more thereof, more preferably selected from the group consisting of ceria, alumina, and mixed oxides comprising one or more of Ce and Al, more preferably selected from the group consisting of ceria, and mixed oxides comprising one or more of Ce and Al, more preferably a mixed oxide comprising Ce and Al, and more preferably a mixed oxide of Ce and Al. Preferably, the weight ratio of Ce:Al calculated as CeO2:Al2O3 is more preferably in the range of 10:90 to 90:10, more preferably in the range of 20:80 to 50:50, more preferably in the range of 25:75 to 50:50.

[0024] Preferably, according to the alternative, at most 0.01 wt.%, more preferably at most 0.001 wt.%, more preferably at most 0.0001 wt.% of the second NA coating consists of barium calculated as BaO. In other words, the second NA coating (iii) is preferably essentially free of barium calculated as BaO, more preferably free of barium. Such an alternative is, for example, illustrated by Example 2.2 herein below.

[0025] In the context of the present invention, it is preferred that the second NA coating (iii) further comprises an oxide component selected from the group consisting of ceria, zirconia, alumina, silica, titania, mixed oxides comprising one or more of Ce, Zr, Al, Si and Ti, and mixtures of two or more thereof, more preferably an oxide component selected from the group consisting of ceria, zirconia, alumina and titania, more preferably an oxide component selected from the group consisting of ceria, zirconia and alumina, more preferably ceria.

[0026] Preferably, 95-100% by weight, more preferably 98-100% by weight, more preferably 99-100% by weight, more preferably 99.5-100% by weight, more preferably 99.9-100% by weight of the oxide component contained in the second NA coating (iii) consists of ceria calculated as CeO2. In other words, it is preferred that the oxide component contained in the second NA coating consists essentially of ceria calculated as CeO2, more preferably consists of ceria.

[0027] Preferably, the second NA coating (iii) has an oxide component of 0.5 to 9 g / in 3 More preferably, in the range of 1 to 8 g / in 3 More preferably, the range is 2 to 6 g / in 3 More preferably, the range is 2.75 to 5 g / in 3 The loading amount is in the range of .

[0028] According to a further alternative in the context of the present invention, the second NA coating (iii) comprises an alkaline earth metal supported on a support material and a platinum group metal component supported on a second non-zeolitic oxide material, as illustrated for example by Example 4 below.

[0029] More preferably, in the second NA coating (iii), the weight ratio of the second non-zeolitic oxide material to the support material is in the range of 0.05:1 to 0.9:1, more preferably in the range of 0.1:1 to 0.7:1, more preferably in the range of 0.15:1 to 0.5:1, more preferably in the range of 0.17:1 to 0.25:1.

[0030] Preferably, the alkaline earth metal supported on the support material contained in the second NA coating (iii) is selected from the group consisting of barium, strontium, calcium and magnesium, more preferably selected from the group consisting of barium, strontium and magnesium, more preferably barium. More preferably, the alkaline earth metal contained in the second NA coating (iii) is present as an oxide, cation and / or carbonate.

[0031] Preferably, the second NA coating (iii) comprises an amount of alkaline earth metal, calculated as oxide, based on the weight of the support material contained in the second NA coating (iii), in the range of 0.25 to 10 wt.-%, more preferably in the range of 0.5 to 8 wt.-%, more preferably in the range of 1 to 6 wt.-%, more preferably in the range of 1.25 to 4 wt.-%, more preferably in the range of 1.5 to 3 wt.-%.

[0032] Preferably, the support material carrying the alkaline earth metal, more preferably barium, in the second NA coating (iii) is selected from the group consisting of ceria, zirconia, alumina, silica, titania, mixed oxides comprising one or more of Ce, Zr, Al, Si and Ti, and mixtures of two or more thereof, more preferably selected from the group consisting of ceria, zirconia, alumina and titania, more preferably selected from the group consisting of ceria, zirconia and alumina, more preferably ceria.

[0033] Preferably 95-100% by weight, more preferably 98-100% by weight, more preferably 99-100% by weight, more preferably 99.5-100% by weight, more preferably 99.9-100% by weight of the support material contained in the second NA coating (iii) consists of ceria calculated as CeO2. In other words, it is preferred that the support material contained in the second NA coating (iii) consists essentially of ceria calculated as CeO2, and more preferably the support material supporting barium in the second NA coating (iii) is ceria.

[0034] Preferably, the second NA coating (iii) is a coating of the alkaline earth metal-loaded support material in a concentration of 0.5 to 9 g / in 3 More preferably, in the range of 1 to 8 g / in 3 More preferably, the range is 2 to 6 g / in 3 More preferably, the range is 2.75 to 5 g / in 3 The loading amount is in the range of .

[0035] In the context of the present invention, the second NA coating (iii) preferably comprises one or more of zirconia, alumina, silica, magnesium oxide, strontium oxide, lanthana, praseodymium oxide, neodymium oxide and titania, more preferably one or more of zirconia, alumina, magnesium oxide and titania, more preferably one or more of zirconia, alumina and magnesium oxide, more preferably one or more of zirconia and magnesium oxide, more preferably zirconia and magnesium oxide. Preferably, the weight ratio of zirconia to magnesium oxide is in the range of 0.5:1 to 1:0.5, more preferably in the range of 0.75:1 to 1:0.75, more preferably in the range of 0.9:1 to 1:0.9.

[0036] Preferably, the second NA coating (iii) comprises the oxide material in an amount in the range of 0.5 to 5 wt. %, more preferably in the range of 1 to 4 wt. %, more preferably in the range of 1.5 to 3.5 wt. %, based on the weight of the second NA coating (iii).

[0037] Preferably, the second NA coating (iii) is disposed on the surface of the inner wall of the substrate (i).

[0038] Preferably, the second NA coating (iii) functions as a lean NOx trap.

[0039] Preferably, at most 0.1 wt. %, preferably at most 0.01 wt. %, more preferably at most 0.001 wt. %, more preferably at most 0.0001 wt. % of the second NA coating (iii) consists of molecular sieves. In other words, preferably, the second NA coating (iii) is essentially free of molecular sieves, more preferably it is free of molecular sieves.

[0040] Preferably 95-100% by weight, more preferably 98-100% by weight, more preferably 99-100% by weight, more preferably 99.5-100% by weight, more preferably 99.9-100% by weight of the second NA coating (iii) consists of a platinum group metal component supported on a second non-zeolitic oxide material, more preferably an oxide component as defined above, more preferably an oxide material as defined above. In other words, the second NA coating (iii) preferably consists essentially of, more preferably consists of, a platinum group metal component supported on a second non-zeolitic oxide material, more preferably an oxide component as defined above, more preferably an oxide material as defined above.

[0041] Alternatively, it is preferred that 95-100% by weight, more preferably 98-100% by weight, more preferably 99-100% by weight, more preferably 99.5-100% by weight, more preferably 99.9-100% by weight of the second NA coating (iii) consists of an alkaline earth metal supported on a support material, a platinum group metal component supported on a second non-zeolitic oxide material, preferably an oxide material as defined above. In other words, it is preferred that the second NA coating (iii) consists essentially of, more preferably consists of, an alkaline earth metal supported on a support material, a platinum group metal component supported on a second non-zeolitic oxide material, more preferably an oxide material as defined above.

[0042] Preferably, the platinum group metal components included in the DOC coating (iv) are one or more of Pt, Pd, Rh, Ir, Ru, and Os, more preferably one or more of Pt, Pd, and Rh, more preferably one or more of Pt and Pd, more preferably Pt and Pd. Preferably, the weight ratio of platinum to palladium, calculated as Pt:Pd, is in the range 2:1 to 20:1, more preferably in the range 5:1 to 15:1, more preferably in the range 7:1 to 12:1, more preferably in the range 8:1 to 10:1.

[0043] Preferably, the DOC coating (iv) has a metal content of 5 to 150 g / ft, calculated as platinum group metal element. 3 More preferably, it is in the range of 10 to 120 g / ft 3 More preferably, it is in the range of 30 to 100 g / ft 3 More preferably, it is in the range of 40 to 80 g / ft 3 More preferably, the range is 45 to 75 g / ft 3 The composition further comprises a platinum group metal component in a loading range of

[0044] Preferably, the third non-zeolitic oxide material contained in the DOC coating (iv) is selected from the group consisting of alumina, zirconia, silica, titania, mixed oxides comprising one or more of Al, Zr, Si and Ti, and mixtures of two or more thereof, more preferably selected from the group consisting of silica, alumina and mixed oxides comprising one or more of Si and Al, more preferably selected from the group consisting of alumina and mixed oxides comprising one or more of Si and Al, more preferably a mixed oxide comprising Si and Al, more preferably a mixed oxide of Si and Al. Preferably 90-99 wt%, more preferably 92-98 wt%, more preferably 93-97 wt% of the second non-zeolitic material contained in the DOC coating (iv) consists of alumina, and preferably 1-10 wt%, more preferably 2-8 wt%, more preferably 3-7 wt% of the DOC coating (iv) consists of silica.

[0045] Preferably, the DOC coating (iv) has a coating density of 0.5 to 3 g / in 3 in the range of 0.75 to 2.5 g / in 3 More preferably, the range is 0.9 to 2 g / in 3 The third non-zeolitic oxide material is present in a loading range of 0.1 to 1.0 μg / g.

[0046] Preferably, the DOC coating (iv) further comprises a zeolitic material comprising one or more of iron and copper, more preferably a zeolitic material comprising iron. Preferably, the DOC coating (iii) comprises iron in an amount in the range of 0.25 to 4 wt.%, more preferably in the range of 0.5 to 3 wt.%, more preferably in the range of 0.75 to 2.5 wt.%, calculated as Fe2O3, based on the weight of the iron-containing zeolitic material comprised in the DOC coating (iv). Alternatively, it is preferred that the DOC coating (iv) further comprises a zeolitic material in the H and / or NH4 form.

[0047] Preferably, the zeolitic material contained in the DOC coating (iv) is a 12-ring pore zeolitic material, more preferably having a framework type selected from the group consisting of BEA, MOR, FAU, GME, OFF, mixtures of two or more thereof and mixed types of two or more thereof, more preferably having a framework type selected from the group consisting of BEA, MOR, FAU, mixtures of two or more thereof and mixed types of two or more thereof, more preferably having a framework type selected from the group consisting of BEA and FAU. More preferably, the 12-ring pore zeolitic material contained in the DOC coating (iv) has the framework type BEA.

[0048] Preferably, 95 to 100% by weight, more preferably 98 to 100% by weight, more preferably 99 to 100% by weight, more preferably 99.5 to 100% by weight of the framework structure of the 12-membered ring pore zeolite material contained in the DOC coating (iv) is composed of Si, Al, and O.

[0049] Preferably, in the framework structure of the 12-ring pore zeolite material contained in the DOC coating (iv), the molar ratio of Si to Al, calculated as molar SiO2:Al2O3, is in the range of 2:1 to 60:1, more preferably in the range of 2:1 to 50:1, more preferably in the range of 5:1 to 40:1, more preferably in the range of 10:1 to 35:1, more preferably in the range of 15:1 to 30:1, more preferably in the range of 20:1 to 30:1, more preferably in the range of 23:1 to 29:1.

[0050] Preferably, the DOC coating (iv) comprises zeolitic material in an amount in the range of 15 to 50 wt%, more preferably in the range of 20 to 45 wt%, more preferably in the range of 25 to 43 wt%, based on the weight of the third non-zeolitic oxide material contained in the DOC coating (iv).

[0051] Preferably, the DOC coating (iv) further comprises an oxide material comprising an alkaline earth metal, more preferably one or more of Ba, Mg, Ca and Sr, more preferably one or more of Ba, Mg and Ca, more preferably one or more of Ba and Mg, more preferably Ba. More preferably, the oxide material comprising an alkaline earth metal is BaO.

[0052] Preferably, the DOC coating (iv) comprises an oxide material in an amount in the range of 1 to 15 wt.%, more preferably in the range of 3 to 10 wt.%, more preferably in the range of 5 to 9 wt.%, based on the weight of the third non-zeolitic oxide material contained in the DOC coating (iv).

[0053] Preferably, the catalyst is present at a concentration of 0.75 to 3.5 g / in 3 More preferably, the range is 0.9 to 3 g / in 3 More preferably, in the range of 1 to 2.5 g / in 3 (iv) a DOC coating having a loading in the range of

[0054] Preferably, at most 0.1 wt.-%, more preferably at most 0.01 wt.-%, more preferably at most 0.001 wt.-%, more preferably at most 0.0001 wt.-%, of the second NA coating (iii) consists of ceria, in other words, the second NA coating (iii) is preferably essentially free of ceria, more preferably free of ceria.

[0055] Preferably 95-100% by weight, more preferably 98-100% by weight, more preferably 99-100% by weight, more preferably 99.5-100% by weight, more preferably 99.9-100% by weight of the DOC coating (iv) consists of a platinum group metal component supported on a third non-zeolitic oxide material, more preferably a zeolitic material comprising one or more of Fe and Cu as defined above, more preferably an oxide material comprising an alkaline earth metal as defined above. In other words, it is preferred that the DOC coating (iv) consists essentially of, more preferably consists of, a platinum group metal component supported on a third non-zeolitic oxide material, more preferably a zeolitic material comprising one or more of Fe and Cu as defined above, more preferably an oxide material comprising an alkaline earth metal as defined above.

[0056] With regard to the substrate (i), it is preferred that it is a flow-through substrate or a wall-flow filter substrate, more preferably a flow-through substrate.

[0057] Preferably, the flow-through substrate (i) comprises, more preferably consists of, a ceramic material, preferably one or more of alumina, silica, silicates, aluminosilicates, more preferably cordierite or mullite, aluminotitanate, silicon carbide, zirconia, magnesia, preferably spinel, and titania, more preferably one or more of silicon carbide and cordierite, more preferably cordierite, more preferably consists of them.

[0058] Alternatively, the flow-through substrate (i) preferably comprises, more preferably consists of, a metal material, which preferably comprises, more preferably consists of, oxygen and one or more of iron, chromium and aluminium.

[0059] The catalyst of the present invention and as defined above preferably consists of a substrate (i), a first NA coating (ii), a second NA coating (iii) and a DOC coating (iv).

[0060] The present invention further provides a process for preparing the NOx adsorber diesel oxidation catalyst (NA-DOC) according to the present invention, comprising: (a) preparing a first mixture comprising water, a source of palladium, and a first non-zeolitic oxide material comprising ceria; (b) disposing the first mixture obtained according to (a) on a surface of an inner wall of a substrate having an inlet end, an outlet end, a substrate axial length extending from the inlet end to the outlet end, and a plurality of passages defined by the substrate's inner wall extending therethrough, over x% of the substrate axial length from the outlet end to the inlet end of the substrate, where x is in the range of 20 to 70, and calcining to obtain a substrate having a first NOx sorbent (NA) coating thereon; (c) preparing a second mixture comprising water and a source of one or more of an alkaline earth metal having a support material for the alkaline earth metal, and a platinum group metal component having a second non-zeolitic oxide material for supporting the platinum group metal component; (d) disposing the second mixture obtained according to (c) on a substrate having a first NA coating thereon over y% of the substrate axial length from the inlet end towards the outlet end of the substrate, where y is in the range of 20-70, and calcining to obtain a substrate having a first NA coating and a second NA coating; (e) preparing a third mixture comprising water, a source of a platinum group metal component, and a third non-zeolitic oxide material; (f) disposing the third mixture obtained according to (e) on a substrate having a first NA coating and a second NA coating thereon over z % of the substrate axial length, where z is in the range of 50 to 100; (g) calcining the substrate obtained according to (f) to obtain a substrate having the first NA coating, the second NA coating, and the DOC coating thereon.

[0061] Preferably, x is in the range of 30 to 65, more preferably in the range of 35 to 60, more preferably in the range of 40 to 55, and more preferably in the range of 45 to 55.

[0062] Preferably, y is in the range of 30 to 65, more preferably in the range of 35 to 60, more preferably in the range of 40 to 55, and more preferably in the range of 45 to 55. More preferably, x is in the range of 45 to 55, and y is in the range of 45 to 55.

[0063] Preferably, y is 100-x, and more preferably, x is in the range of 45-55.

[0064] Preferably, z is in the range of 70 to 100, more preferably in the range of 80 to 100, more preferably in the range of 90 to 100, more preferably in the range of 95 to 100, more preferably in the range of 98 to 100, and more preferably in the range of 99 to 100.

[0065] Regarding (a), (a.1) impregnating a source of palladium, more preferably a palladium salt, more preferably palladium nitrate, onto a first non-zeolitic oxide material comprising ceria; (a.2) calcining the impregnated material obtained in (a.1), preferably drying it before calcination, to obtain a powder; (a.3) mixing water with the powder obtained in (a.2).

[0066] With regard to (b), it is preferred that the method further comprises drying before calcination, the drying being carried out in a gas atmosphere having a temperature in the range of 90 to 160° C., more preferably in the range of 100 to 120° C. Preferably, the gas atmosphere comprises oxygen.

[0067] Preferably, the calcination according to (b) is carried out in a gas atmosphere having a temperature in the range of from 300 to 800° C., more preferably in the range of from 400 to 700° C. Preferably, the gas atmosphere comprises oxygen.

[0068] Regarding (c), (c.1) impregnating a source of a platinum group metal component, more preferably a source of platinum and palladium, onto a second non-zeolitic oxide material; (c.2) calcining the impregnated material obtained in (c.1), preferably drying before calcination, to obtain a powder; (c.3) mixing water with the powder obtained in (c.2); (c.4) mixing the aqueous mixture obtained in (c.3) with an oxide component, more preferably an oxide component as defined above, (c.5) preferably comprising adding to the aqueous mixture obtained in (c.4) an oxide material, preferably as defined above.

[0069] Or, (c) is (c.1') impregnating a source of a platinum group metal component, more preferably a source of platinum and palladium, onto a second non-zeolitic oxide material; (c.2') calcining the impregnated material obtained in (c.1'), preferably drying before calcination, to obtain a powder; (c.3') impregnating an alkaline earth metal onto a support material; (c.4') calcining the impregnated material obtained in (c.3'), preferably drying before calcination, to obtain a powder; (c.5') mixing water with the powder obtained in (c.2') and the powder obtained in (c.4'); (c.6') More preferably, the method comprises adding to the aqueous mixture obtained in (c.5') an oxide material, preferably as defined above.

[0070] With regard to (d), it is preferred that the method further comprises drying before calcination, the drying being carried out in a gas atmosphere having a temperature in the range of 90 to 160° C., more preferably in the range of 100 to 120° C. Preferably, the gas atmosphere comprises oxygen.

[0071] Preferably, the calcination according to (d) is carried out in a gas atmosphere having a temperature in the range of from 300 to 800° C., more preferably in the range of from 400 to 700° C. Preferably, the gas atmosphere comprises oxygen.

[0072] Regarding (e): (e.1) impregnating a source of a platinum group metal component, more preferably a source of platinum and palladium, onto a third non-zeolitic oxide material; (e.2) impregnating the material obtained in (e.1) with barium hydroxide; (e.3) mixing water with the impregnated material obtained in (e.2); (e.4) More preferably, the method comprises mixing the aqueous mixture obtained in (e.3) with a zeolitic material containing one or more of iron and copper as defined above.

[0073] Preferably, (f) further comprises drying the substrate on which the third mixture is disposed, the drying being carried out in a gas atmosphere having a temperature in the range of 90 to 160° C., more preferably in the range of 100 to 120° C. Preferably, the gas atmosphere comprises oxygen.

[0074] Preferably, the calcination of the substrate according to (g) is carried out in a gas atmosphere having a temperature in the range of from 300 to 800° C., more preferably in the range of from 400 to 700° C. Preferably, the gas atmosphere comprises oxygen.

[0075] Preferably, the process comprises (a), (b), (c), (d), (e), (f), and (g).

[0076] The present invention further relates to a NOx adsorber diesel oxidation catalyst (NA-DOC) obtained or obtainable by the above defined process according to the invention.

[0077] The present invention further relates to the use of the above defined NOx adsorber diesel oxidation catalyst (NA-DOC) according to the invention for the adsorption / desorption of NOx and the conversion of HC and CO.

[0078] The present invention further provides an exhaust gas treatment system for treating an exhaust gas, comprising: comprising the above-defined NOx adsorber diesel oxidation (NA-DOC) catalyst according to the present invention, Preferably, the exhaust gas treatment system further comprises one or more of a selective catalytic reduction (SCR) catalyst, a selective catalytic reduction catalyst on a filter (SCRoF), and an ammonia oxidation (AMOX) catalyst.

[0079] Preferably, the NA-DOC catalyst is located upstream of one or more of a selective catalytic reduction (SCR) catalyst, a selective catalytic reduction on filter catalyst (SCRoF), and an ammonia oxidation (AMOX) catalyst.

[0080] Preferably, the system comprises a NOx adsorber diesel oxidation (NA-DOC) catalyst according to the present invention as defined above, an SCR catalyst and an AMOX catalyst, The NA-DOC catalyst is positioned upstream of the SCR catalyst, which is positioned upstream of the AMOX catalyst.

[0081] Preferably, the system further comprises a SCRoF catalyst, more preferably the SCRoF catalyst is located upstream of the SCR catalyst and downstream of the NA-DOC catalyst, or more preferably the SCRoF catalyst is located downstream of the SCR catalyst and upstream of the AMOX catalyst.

[0082] Preferably, the system further comprises another SCR catalyst arranged upstream of the AMOX catalyst. If the SCRoF catalyst is arranged upstream of the SCR catalyst and downstream of the NA-DOC catalyst, the other SCR catalyst is preferably arranged downstream of the SCR catalyst and upstream of the AMOX catalyst. Alternatively, if the SCRoF catalyst is arranged downstream of the SCR catalyst and upstream of the AMOX catalyst, the other SCR catalyst is preferably arranged downstream of the SCRoF catalyst and upstream of the AMOX catalyst.

[0083] Alternatively, the system preferably comprises a NOx adsorber diesel oxidation (NA-DOC) catalyst according to the present invention as defined above, a SCRoF catalyst and an AMOX catalyst, The NA-DOC catalyst is placed upstream of the SCRoF catalyst, which is placed upstream of the AMOX catalyst.

[0084] Thus, the system may preferably be as follows: -NA-DOC cat. / SCR cat. / AMOX cat.; -NA-DOC cat. / SCR cat. / SCRoF cat. / AMOX cat.; -NA-DOC cat. / SCR cat. / SCRoF cat. / SCR cat. / AMOX cat.; -NA-DOC cat. / SCRoF cat. / AMOX cat.; -NA-DOC cat. / SCRoF cat. / SCR cat. / AMOX cat.; or -NA-DOC cat. / SCRoF cat. / SCR cat. / SCR cat. / AMOX cat.

[0085] It should be noted that in the context of the present invention, SCR catalyst, SCRoF catalyst and AMOX catalyst may be as defined in the art. A person skilled in the art knows which types of catalysts may be used for these purposes. NA-DOC catalyst is the above defined catalyst of the present invention.

[0086] The present invention further comprises providing exhaust gas, preferably from an internal combustion engine, more preferably from a diesel engine; contacting the exhaust gas with a NOx adsorber diesel oxidation catalyst according to the present invention as defined above; The present invention relates to a method for the treatment of exhaust gases, comprising:

[0087] The present invention is further described by the following set of embodiments and combinations of embodiments resulting from dependencies and reverse references as indicated. In particular, in the context of the present invention, in each instance where a range of embodiments is mentioned, it is to be noted that in the context of terms such as, for example, "the catalyst according to any one of embodiments 1 to 5", all embodiments in this range are expressly disclosed to those skilled in the art, i.e., the expression of this term is understood by those skilled in the art to be synonymous with "the catalyst according to any one of embodiments 1, 2, 3, 4, and 5". Furthermore, it is to be clearly noted that the following set of embodiments represents a properly structured part of the description directed to the general and preferred aspects of the present invention, rather than a set of claims defining the scope of protection. It is to be noted that this is equally applicable to the second set of embodiments.

[0088] 1. A NOx adsorber diesel oxidation catalyst (NA-DOC) for treating exhaust gas, comprising: (i) a substrate comprising an inlet end, an outlet end, a substrate axial length extending from the inlet end to the outlet end, and a plurality of passages defined by an interior wall of the substrate extending therethrough; (ii) a first NOx sorbent (NA) coating comprising palladium supported on a first non-zeolitic oxide material comprising ceria; and (iii) a second NOx sorbent (NA) coating comprising one or more of an alkaline earth metal supported on a support material and a platinum group metal component supported on a second non-zeolitic oxide material; and (iv) a diesel oxidation catalyst (DOC) coating, the DOC coating comprising a platinum group metal component supported on a third non-zeolitic oxide material; a first NA coating (ii) is disposed on a surface of an inner wall of the substrate (i) over x% of the substrate axial length from the exit end towards the entrance end of the substrate, where x is in the range of 20 to 70; a second NA coating (iii) disposed over y % of the substrate axial length from the inlet end towards the outlet end, y being in the range of 20 to 70; A NOx adsorber diesel oxidation catalyst, wherein a DOC coating is disposed on the first NA coating and the second NA coating, or on the first NA coating, the second NA coating, and a surface of an inner wall of the substrate, over z% of the axial length of the substrate, and z is in the range of 50 to 100. 2. The catalyst according to embodiment 1, wherein x is in the range of 30 to 65, preferably in the range of 35 to 60, more preferably in the range of 40 to 55, more preferably in the range of 45 to 55. 3. The catalyst according to embodiment 1 or 2, wherein y is in the range of 30 to 65, preferably in the range of 35 to 60, more preferably in the range of 40 to 55, more preferably in the range of 45 to 55. 4. The catalyst according to any one of the preceding embodiments, wherein y is 100-x, preferably x is in the range of 45 to 55. 5. The catalyst according to any one of embodiments 1 to 4, wherein z is in the range of 70 to 100, preferably in the range of 80 to 100, more preferably in the range of 90 to 100, more preferably in the range of 95 to 100, more preferably in the range of 98 to 100, more preferably in the range of 99 to 100. 6. The catalyst according to any one of the preceding embodiments, wherein 95-100% by weight, preferably 98-100% by weight, more preferably 99-100% by weight, more preferably 99.5-100% by weight, more preferably 99.9-100% by weight of the first non-zeolitic oxide material contained in the first NA coating (ii) consists of ceria, calculated as CeO2. 7. The first NA coating (ii) has a coating weight of 5 to 150 g / ft, calculated as elemental Pd. 3 range, preferably 10 to 120 g / ft 3 More preferably, it is in the range of 30 to 100 g / ft 3 More preferably, it is in the range of 40 to 80 g / ft 3 More preferably, the range is 45 to 75 g / ft 37. The catalyst of any one of the preceding embodiments, comprising a palladium loading in the range of 8. The first NA coating is 1-6g / in 3 in the range of 2 to 5 g / in 3 More preferably, the range is 2.5 to 4.5 g / in 3 8. The catalyst of any one of the preceding embodiments, comprising a loading of the first non-zeolitic oxide material in the range of 9. The catalyst according to any one of the preceding embodiments, wherein at most 0.01 wt.-%, preferably at most 0.001 wt.-%, more preferably at most 0.0001 wt.-% of the first NA coating consists of barium, calculated as BaO. 10. The catalyst according to any one of the preceding embodiments, wherein at most 0.01 wt.-%, preferably at most 0.001 wt.-%, more preferably at most 0.0001 wt.-% of the first NA coating consists of molecular sieves. 11. The catalyst according to any one of the preceding embodiments, wherein 95-100% by weight, preferably 98-100% by weight, more preferably 99-100% by weight, more preferably 99.5-100% by weight, more preferably 99.9-100% by weight of the first NA coating (ii) consists of palladium on a first non-zeolitic oxide material, preferably palladium on ceria. 12. The catalyst of any one of embodiments 1 to 11, wherein the first NA coating (iii) prevents irreversible damage from sulfation / desulfation and functions as a lean NOx trap. 13. Apply the second NA coating at 1.5 to 8 g / in 3 More preferably, the range is 2 to 7 g / in 3 More preferably, the range is 3 to 6.5 g / in 3 More preferably, the range is 3.5 to 5.5 g / in 3 13. The catalyst of any one of embodiments 1 to 12, wherein the catalyst comprises a loading in the range of 14. The second NA coating (iii) comprises a platinum group metal component, the platinum group metal component being one or more of Pt, Pd, Rh, Ir, Ru, and Os, preferably one or more of Pt, Pd, and Rh, more preferably one or more of Pt and Pd, more preferably Pt and Pd; 14. The catalyst according to any one of the preceding embodiments, wherein the weight ratio of platinum to palladium, calculated as Pt:Pd, is preferably in the range of 5:1 to 15:1, more preferably in the range of 7:1 to 12:1, more preferably in the range of 8:1 to 10:1. 15. The second NA coating (iii) has a mass of 5 to 150 g / ft, calculated as platinum group metal elements. 3 range, preferably 10 to 120 g / ft 3 More preferably, it is in the range of 30 to 100 g / ft 3 More preferably, it is in the range of 40 to 80 g / ft 3 More preferably, the range is 45 to 75 g / ft 3 15. The catalyst of any one of embodiments 1-14, comprising a platinum group metal component loaded in the range of 16. In the second NA coating (iii), the second non-zeolitic oxide material supporting the platinum group metal component is selected from the group consisting of ceria, alumina, zirconia, silica, titania, mixed oxides comprising one or more of Ce, Al, Zr, Si, and Ti, and mixtures of two or more thereof, preferably selected from the group consisting of ceria, alumina, and mixed oxides comprising one or more of Ce and Al, more preferably selected from the group consisting of ceria and mixed oxides comprising one or more of Ce and Al, more preferably a mixed oxide comprising Ce and Al, more preferably a mixed oxide of Ce and Al; 16. The catalyst according to any one of embodiments 1 to 15, wherein the weight ratio of Ce:Al, calculated as CeO2:Al2O3, is more preferably in the range of 10:90 to 90:10, more preferably in the range of 20:80 to 50:50, more preferably in the range of 25:75 to 50:50. 17. The catalyst according to any one of the preceding embodiments, wherein at most 0.01 wt.-%, preferably at most 0.001 wt.-%, more preferably at most 0.0001 wt.-% of the second NA coating consists of barium, calculated as BaO. 18. The catalyst according to any one of the preceding embodiments, wherein the second NA coating (iii) further comprises an oxide component selected from the group consisting of ceria, zirconia, alumina, silica, titania, mixed oxides comprising one or more of Ce, Zr, Al, Si, and Ti, and mixtures of two or more thereof, more preferably an oxide component selected from the group consisting of ceria, zirconia, alumina, and titania, more preferably an oxide component selected from the group consisting of ceria, zirconia, and alumina, more preferably ceria. 19. The catalyst according to embodiment 18, wherein 95-100% by weight, preferably 98-100% by weight, more preferably 99-100% by weight, more preferably 99.5-100% by weight, more preferably 99.9-100% by weight of the oxide component contained in the second NA coating (iii) consists of ceria, calculated as CeO2. 20. The second NA coating (iii) is applied with an oxide component at a concentration of 0.5 to 9 g / in 3 in the range of 1 to 8 g / in 3 More preferably, the range is 2 to 6 g / in 3 More preferably, the range is 2.75 to 5 g / in 3 20. The catalyst of embodiment 18 or 19, comprising a loading in the range of 21. The catalyst of any one of the preceding embodiments, wherein the second NA coating (iii) comprises an alkaline earth metal supported on a support material and a platinum group metal component supported on a second non-zeolitic oxide material. 22. The catalyst according to embodiment 21, wherein in the second NA coating (iii) the weight ratio of the second non-zeolitic oxide material to the support material is in the range of 0.05:1 to 0.9:1, preferably in the range of 0.1:1 to 0.7:1, more preferably in the range of 0.15:1 to 0.5:1, more preferably in the range of 0.17:1 to 0.25:1. 23. The alkaline earth metal supported on the support material contained in the second NA coating (iii) is selected from the group consisting of barium, strontium, calcium and magnesium, preferably selected from the group consisting of barium, strontium and magnesium, more preferably barium; 23. The catalyst of any one of embodiments 1 to 16, 21, and 22, wherein the alkaline earth metal included in the second NA coating (iii) is preferably present as an oxide, a cation, and / or a carbonate. 24. The catalyst according to any one of embodiments 1 to 16 and 21 to 23, wherein the second NA coating (iii) comprises an amount of alkaline earth metal, calculated as oxide, based on the weight of the support material contained in the second NA coating (iii), in the range of 0.25 to 10 wt.%, more preferably in the range of 0.5 to 8 wt.%, more preferably in the range of 1 to 6 wt.%, more preferably in the range of 1.25 to 4 wt.%, more preferably in the range of 1.5 to 3 wt.%. 25. The catalyst of any one of embodiments 1 to 16 and 21 to 24, wherein the support material carrying the alkaline earth metal, preferably barium, in the second NA coating (iii) is selected from the group consisting of ceria, zirconia, alumina, silica, titania, mixed oxides containing one or more of Ce, Zr, Al, Si, and Ti, and mixtures of two or more thereof, more preferably selected from the group consisting of ceria, zirconia, alumina, and titania, more preferably selected from the group consisting of ceria, zirconia, and alumina, more preferably ceria. 26. The catalyst according to embodiment 25, wherein 95-100% by weight, preferably 98-100% by weight, more preferably 99-100% by weight, more preferably 99.5-100% by weight, more preferably 99.9-100% by weight of the support material in the second NA coating (iii) consists of ceria, calculated as CeO2. 27. The second NA coating (iii) is applied to the support material carrying the alkaline earth metal at a concentration of 0.5 to 9 g / in 3 in the range of 1 to 8 g / in 3 More preferably, the range is 2 to 6 g / in3 More preferably, the range is 2.75 to 5 g / in 3 The catalyst of any one of embodiments 1 to 16 and 21 to 26, wherein the catalyst comprises a loading in the range of 28. The second NA coating (iii) comprises one or more of zirconia, alumina, silica, magnesium oxide, strontium oxide, lanthana, praseodymium oxide, neodymium oxide, and titania, more preferably one or more of zirconia, alumina, magnesium oxide, and titania, more preferably one or more of zirconia, alumina, and magnesium oxide, more preferably one or more of zirconia and magnesium oxide, more preferably zirconia and magnesium oxide; 28. The catalyst according to any one of the preceding embodiments, wherein the weight ratio of zirconia to magnesium oxide is preferably in the range of 0.5:1 to 1:0.5, more preferably in the range of 0.75:1 to 1:0.75, more preferably in the range of 0.9:1 to 1:0.9. 29. The catalyst of embodiment 28, wherein the second NA coating (iii) comprises an oxide material in an amount in the range of 0.5 to 5 wt.%, preferably in the range of 1 to 4 wt.%, more preferably in the range of 1.5 to 3.5 wt.%, based on the weight of the second NA coating (iii). 30. The catalyst of any one of the preceding embodiments, wherein a second NA coating (iii) is disposed on the surface of the inner wall of the substrate (i). 31. The catalyst of any one of embodiments 1 to 30, wherein the second NA coating (iii) functions as a lean NOx trap. 32. The catalyst according to any one of embodiments 1 to 31, wherein at most 0.1 wt.-%, preferably at most 0.01 wt.-%, more preferably at most 0.001 wt.-%, more preferably at most 0.0001 wt.-% of the second NA coating (iii) consists of molecular sieves. 33. The catalyst according to any one of embodiments 1 to 20 and 28 to 32, wherein 95 to 100 wt.-%, more preferably 98 to 100 wt.-%, preferably 99 to 100 wt.-%, more preferably 99.5 to 100 wt.-%, more preferably 99.9 to 100 wt.-% of the second NA coating (iii) consists of a platinum group metal component supported on a second non-zeolitic oxide material, preferably an oxide component as defined in any one of embodiments 18 to 20, more preferably an oxide material as defined in embodiment 28 or 29. 34. The catalyst according to any one of embodiments 1 to 16 and 21 to 32, wherein 95 to 100% by weight, more preferably 98 to 100% by weight, more preferably 99 to 100% by weight, more preferably 99.5 to 100% by weight, more preferably 99.9 to 100% by weight of the second NA coating (iii) consists of an alkaline earth metal supported on a support material, a platinum group metal component supported on a second non-zeolitic oxide material, preferably an oxide material as defined in embodiment 28 or 29. 35. The platinum group metal component in the DOC coating (iv) is one or more of Pt, Pd, Rh, Ir, Ru, and Os, preferably one or more of Pt, Pd, and Rh, more preferably one or more of Pt and Pd, more preferably Pt and Pd; 35. The catalyst according to any one of embodiments 1 to 34, wherein the weight ratio of platinum to palladium, calculated as Pt:Pd, is preferably in the range of 2:1 to 20:1, more preferably in the range of 5:1 to 15:1, more preferably in the range of 7:1 to 12:1, more preferably in the range of 8:1 to 10:1. 36. The DOC coating (iv) contains 5 to 150 g / ft2 of platinum group metal elements. 3 range, preferably 10 to 120 g / ft 3 More preferably, it is in the range of 30 to 100 g / ft 3 More preferably, it is in the range of 40 to 80 g / ft 3 More preferably, the range is 45 to 75 g / ft 3 36. The catalyst of embodiment 35, further comprising a platinum group metal component in a loading range. 37. The third non-zeolitic oxide material in the DOC coating (iv) is selected from the group consisting of alumina, zirconia, silica, titania, mixed oxides comprising one or more of Al, Zr, Si, and Ti, and mixtures of two or more thereof, preferably selected from the group consisting of silica, alumina, and mixed oxides comprising one or more of Si and Al, more preferably selected from the group consisting of alumina and mixed oxides comprising one or more of Si and Al, more preferably a mixed oxide comprising Si and Al, more preferably a mixed oxide of Si and Al; 37. The catalyst according to any one of the preceding embodiments, wherein preferably 90-99 wt.%, more preferably 92-98 wt.%, more preferably 93-97 wt.% of the second non-zeolitic material in the DOC coating (iv) consists of alumina, and preferably 1-10 wt.%, more preferably 2-8 wt.%, more preferably 3-7 wt.% of the DOC coating (iv) consists of silica. 38.DOC coating is 0.5~3g / in 3 in the range of 0.75 to 2.5 g / in 3 More preferably, the range is 0.9 to 2 g / in 3 38. The catalyst of any one of the preceding embodiments, comprising a third non-zeolitic oxide material having a loading in the range of 39. The DOC coating (iv) further comprises a zeolitic material containing one or more of iron and copper, preferably a zeolitic material containing iron; the DOC coating (iii) comprises an amount of iron, calculated as Fe2O3, in the range of 0.25 to 4 wt.%, more preferably in the range of 0.5 to 3 wt.%, more preferably in the range of 0.75 to 2.5 wt.%, based on the weight of the iron-containing zeolitic material contained in the DOC coating (iv); or 39. The catalyst of any one of the preceding embodiments, wherein the DOC coating (iv) further comprises a zeolitic material in the H and / or NH4 form. 40. Catalyst according to embodiment 39, wherein the zeolitic material comprised in the DOC coating (iv) is a 12-ring pore zeolitic material, the zeolitic material preferably having a framework type selected from the group consisting of BEA, MOR, FAU, GME, OFF, mixtures of two or more thereof and mixed types of two or more thereof, more preferably a framework type selected from the group consisting of BEA, MOR, FAU, mixtures of two or more thereof and mixed types of two or more thereof, more preferably a framework type selected from the group consisting of BEA and FAU, more preferably the 12-ring pore zeolitic material comprised in the DOC coating (iv) has framework type BEA. 41. The catalyst according to embodiment 40, wherein 95 to 100% by weight, preferably 98 to 100% by weight, more preferably 99 to 100% by weight, more preferably 99.5 to 100% by weight of the framework structure of the 12-ring pore zeolite material contained in the DOC coating (iv) is composed of Si, Al and O, and the molar ratio of Si to Al in the framework structure, calculated as molar SiO2:Al2O3, is preferably in the range of 2:1 to 60:1, more preferably in the range of 2:1 to 50:1, more preferably in the range of 5:1 to 40:1, more preferably in the range of 10:1 to 35:1, more preferably in the range of 15:1 to 30:1, more preferably in the range of 20:1 to 30:1, more preferably in the range of 23:1 to 29:1. 42. A catalyst according to any one of embodiments 39 to 41, wherein the DOC coating (iv) comprises an amount of zeolitic material in the range of 15 to 50 wt.%, preferably in the range of 20 to 45 wt.%, more preferably in the range of 25 to 43 wt.%, based on the weight of the third non-zeolitic oxide material contained in the DOC coating (iv). 43. The DOC coating (iv) further comprises an oxide material comprising an alkaline earth metal, the alkaline earth metal being preferably one or more of Ba, Mg, Ca, and Sr, more preferably one or more of Ba, Mg, and Ca, more preferably one or more of Ba and Mg, more preferably Ba, and the oxide material comprising an alkaline earth metal is more preferably BaO; 43. The catalyst of any one of the preceding embodiments, wherein the DOC coating (iv) comprises an oxide material in an amount in the range of 1 to 15 wt.%, more preferably in the range of 3 to 10 wt.%, more preferably in the range of 5 to 9 wt.%, based on the weight of the third non-zeolitic oxide material contained in the DOC coating (iv). 44.0.75~3.5g / in 3 in the range of 0.9 to 3 g / in 3 More preferably, in the range of 1 to 2.5 g / in 3 44. The catalyst of any one of the preceding embodiments, comprising a DOC coating with a loading in the range of: 45. The catalyst according to any one of the preceding embodiments, wherein at most 0.1 wt.-%, preferably at most 0.01 wt.-%, more preferably at most 0.001 wt.-%, more preferably at most 0.0001 wt.-% of the second NA coating (iii) consists of ceria. 46. ​​The catalyst according to any one of the preceding embodiments, wherein 95-100 wt.%, preferably 98-100 wt.%, more preferably 99-100 wt.%, more preferably 99.5-100 wt.%, more preferably 99.9-100 wt.% of the DOC coating (iv) consists of a platinum group metal component supported on a third non-zeolitic oxide material, preferably a zeolitic material comprising one or more of Fe and Cu as defined in any one of the preceding embodiments 39-42, more preferably an oxide material comprising an alkaline earth metal as defined in embodiment 43. 47. The catalyst according to any one of the preceding embodiments, wherein the substrate (i) is a flow-through substrate or a wall-flow filter substrate, preferably a flow-through substrate. 48. The catalyst of embodiment 47, wherein the flow-through substrate (i) comprises, and preferably consists of, a ceramic material, which preferably comprises, and more preferably consists of, one or more of alumina, silica, silicate, aluminosilicate, preferably cordierite or mullite, aluminotitanate, silicon carbide, zirconia, magnesia, preferably spinel, and titania, more preferably one or more of silicon carbide and cordierite, more preferably cordierite. 49. The catalyst of embodiment 47, wherein the flow-through substrate (i) comprises, and preferably consists of, a metal material, the metal material preferably comprising, and more preferably consisting of, oxygen and one or more of iron, chromium, and aluminum. 50. The catalyst of any one of the preceding embodiments, comprising a substrate (i), a first NA coating (ii), a second NA coating (iii), and a DOC coating (iv). 51. A process for preparing a NOx adsorbent diesel oxidation catalyst (NA-DOC) according to any one of embodiments 1 to 50, comprising: (a) preparing a first mixture comprising water, a source of palladium, and a first non-zeolitic oxide material comprising ceria; (b) disposing the first mixture obtained according to (a) on a surface of an inner wall of a substrate having an inlet end, an outlet end, a substrate axial length extending from the inlet end to the outlet end, and a plurality of passages defined by the substrate's inner wall extending therethrough, over x% of the substrate axial length from the outlet end to the inlet end of the substrate, where x is in the range of 20 to 70, and calcining to obtain a substrate having a first NOx sorbent (NA) coating thereon; (c) preparing a second mixture comprising water and a source of one or more of an alkaline earth metal having a support material for the alkaline earth metal, and a platinum group metal component having a second non-zeolitic oxide material for supporting the platinum group metal component; (d) disposing the second mixture obtained according to (c) on a substrate having a first NA coating thereon over y% of the substrate axial length from the inlet end towards the outlet end of the substrate, where y is in the range of 20-70, and calcining to obtain a substrate having a first NA coating and a second NA coating; (e) preparing a third mixture comprising water, a source of a platinum group metal component, and a third non-zeolitic oxide material; (f) disposing the third mixture obtained according to (e) on a substrate having the first NA coating and the second NA coating thereon over z % of the substrate axial length, where z is in the range of 50 to 100; (g) calcining the substrate obtained according to (f) to obtain a substrate having thereon the first NA coating, the second NA coating, and a DOC coating. 52.(a) is (a.1) impregnating a source of palladium, preferably a palladium salt, more preferably palladium nitrate, onto a first non-zeolitic oxide material comprising ceria; (a.2) calcining the impregnated material obtained in (a.1), preferably drying before calcination, to obtain a powder; 51. The process of embodiment 50, comprising: (a.3) mixing water with the powder obtained in (a.2). 53. The process of embodiment 51 or 52, wherein (b) further comprises drying prior to calcination, and the drying is carried out in a gas atmosphere having a temperature in the range of 90 to 160°C, preferably in the range of 100 to 120°C, and the gas atmosphere preferably comprises oxygen. 54. The process according to any one of embodiments 51 to 53, wherein the calcination according to (b) is carried out in a gas atmosphere having a temperature in the range of 300 to 800°C, preferably in the range of 400 to 700°C, and the gas atmosphere preferably contains oxygen. 55.(c) (c.1) impregnating a source of platinum group metal components, preferably a source of platinum and palladium, onto a second non-zeolitic oxide material; (c.2) calcining the impregnated material obtained in (c.1), preferably drying before calcination, to obtain a powder; (c.3) mixing water with the powder obtained in (c.2); (c.4) mixing the aqueous mixture obtained in (c.3) with an oxide component, preferably as defined in any one of embodiments 18 to 20; The process of any one of embodiments 51 to 54, preferably comprising (c.5) adding to the aqueous mixture obtained in (c.4) an oxide material, preferably as defined in embodiment 28 or 29. 56.(c) (c.1') impregnating a source of platinum group metal components, preferably a source of platinum and palladium, onto a second non-zeolitic oxide material; (c.2) calcining the impregnated material obtained in (c.1'), preferably drying before calcination, to obtain a powder; (c.3') impregnating an alkaline earth metal onto a support material; (c.4') calcining the impregnated material obtained in (c.3'), preferably drying before calcination, to obtain a powder; (c.5') mixing water with the powder obtained in (c.2') and the powder obtained in (c.4'); The process according to any one of embodiments 51 to 54, preferably comprising (c.6') adding to the aqueous mixture obtained in (c.5') an oxide material, preferably as defined in embodiment 28 or 29. 57. The process of any one of embodiments 51 to 56, wherein (d) further comprises drying prior to calcination, and the drying is carried out in a gas atmosphere having a temperature in the range of 90 to 160°C, preferably in the range of 100 to 120°C, and the gas atmosphere preferably comprises oxygen. 58. The process of any one of embodiments 51 to 57, wherein the calcination according to (d) is carried out in a gas atmosphere having a temperature in the range of 300 to 800 °C, preferably in the range of 400 to 700 °C, and the gas atmosphere preferably contains oxygen. 59.(e) is (e.1) impregnating a source of platinum group metal components, preferably a source of platinum and palladium, onto a third non-zeolitic oxide material; (e.2) impregnating the material obtained in (e.1) with barium hydroxide; (e.3) mixing water with the impregnated material obtained in (e.2); (e.4) The process according to any one of embodiments 51 to 58, preferably comprising mixing the aqueous mixture obtained in (e.3) with a zeolitic material comprising one or more of iron and copper as defined in any one of embodiments 39 to 42. 60. The process of any one of embodiments 51-59, wherein (f) further comprises drying the substrate on which the third mixture is disposed, and the drying is carried out in a gas atmosphere having a temperature in the range of 90-160°C, preferably in the range of 100-120°C, and the gas atmosphere preferably comprises oxygen. 61. The process according to any one of embodiments 51 to 60, wherein the calcination of the substrate according to (g) is carried out in a gas atmosphere having a temperature in the range of 300 to 800 °C, preferably in the range of 400 to 700 °C, and the gas atmosphere preferably contains oxygen. 62. The process of any one of embodiments 51 to 61, comprising (a), (b), (c), (d), (e), (f), and (g). 63. A NOx adsorber diesel oxidation catalyst (NA-DOC) obtained or obtainable by the process according to any one of embodiments 51 to 62. 64. Use of a NOx adsorber diesel oxidation catalyst (NA-DOC) according to any one of embodiments 1 to 50 and 63 for the adsorption / desorption of NOx and conversion of HC and CO. 65. An exhaust gas treatment system for treating exhaust gas, comprising: The NOx adsorber diesel oxidation (NA-DOC) catalyst according to any one of embodiments 1 to 50 and 63, Preferably, the exhaust treatment system further comprises one or more of a selective catalytic reduction (SCR) catalyst, a selective catalytic reduction on filter catalyst (SCRoF), and an ammonia oxidation (AMOX) catalyst. 66. The system of embodiment 65, wherein the NA-DOC catalyst is preferably located upstream of one or more of a selective catalytic reduction (SCR) catalyst, a selective catalytic reduction on filter catalyst (SCRoF), and an ammonia oxidation (AMOX) catalyst. 67. A NOx adsorber diesel oxidation (NA-DOC) catalyst, an SCR catalyst, and an AMOX catalyst according to any one of embodiments 1 to 50 and 63, 67. The system of embodiment 65 or 66, wherein the NA-DOC catalyst is disposed upstream of the SCR catalyst, and the SCR catalyst is disposed upstream of the AMOX catalyst. 68. Further comprising a SCRoF catalyst; The SCRoF catalyst is located upstream of the SCR catalyst and downstream of the NA-DOC catalyst; or 68. The system of embodiment 67, wherein the SCRoF catalyst is positioned downstream of the SCR catalyst and upstream of the AMOX catalyst. 69. The system of embodiment 68, further comprising a separate SCR catalyst disposed upstream of the AMOX catalyst. 70. A catalyst comprising a NOx adsorber diesel oxidation (NA-DOC) catalyst, an SCRoF catalyst, and an AMOX catalyst according to any one of embodiments 1 to 50 and 63; 67. The system of embodiment 65 or 66, wherein the NA-DOC catalyst is disposed upstream of the SCR catalyst and the SCRoF catalyst is disposed upstream of the AMOX catalyst. 71. A method for treating exhaust gas, comprising: providing exhaust gas preferably from an internal combustion engine, more preferably from a diesel engine; and contacting the exhaust gas with the NOx adsorber diesel oxidation catalyst of any one of embodiments 1 to 50 and 63.

[0089] In the context of the present invention, (g / in 3 or g / ft 3 The term "loading of a given component / coating" (expressed in g / in) refers to the mass of that component / coating per volume of substrate, where the volume of the substrate is the volume defined by the cross-section of the substrate multiplied by the axial length of the substrate on which that component / coating is present. For example, a mass of a given component / coating extending over x% of the substrate axial length and having a mass of X g / in 3 When referring to a coating loading having a loading of 0.01g, the loading is taken as the total volume of the substrate (in 3 ) refers to X grams of coating per x% of the coating.

[0090] Furthermore, in the context of the present invention, the term "inner wall surface" is understood to mean the "bare" or "bare" or "blank" surface of the wall, i.e. the surface of the wall in its untreated state consisting of the wall material apart from any unavoidable impurities that may be mixed into the surface.

[0091] Furthermore, in the context of the present invention, the term "X is one or more of A, B, and C" (X is a given feature and each of A, B, and C represents a specific realization of that feature) should be understood as disclosing that X is either A, or B, or C, or A and B, or A and C, or B and C, or A and B and C. In this regard, it should be noted that a person skilled in the art can translate the above abstract terms into concrete examples. For example, X is a chemical element and A, B, and C are specific elements such as Li, Na, and K, or X is a temperature and A, B, and C are specific temperatures such as 10°C, 20°C, and 30°C. In this regard, it is further noted that one of skill in the art may extend the above terms to less specific recognition of the feature (e.g., "X is one or more of A and B" discloses that X is either A, or B, or A and B), or more specific recognition of the feature (e.g., "X is one or more of A, B, C, and D" discloses that X is either A, or B, or C, or D, or A and B, or A and C, or A and D, or B and C, or B and D, or C and D, or A and B and C, or A and B and D, or B and C and D, or A and B and C and D).

[0092] The present invention is further illustrated by the following examples. EXAMPLES

[0093] Reference example 1 1.1 Measurement of BET specific surface area The BET specific surface area was determined according to DIN 66131 or DIN ISO 9277 using liquid nitrogen.

[0094] 1.2 Determination of crystallinity The determination of the relative crystallinity of the zeolites was performed by X-ray diffraction using test methods under the jurisdiction of ASTM Committee on Catalysts D32, specifically Subcommittee on Zeolites D32.05. The current version was approved on March 10, 2001, and published in May 2001, originally published as D 5758-95.

[0095] 1.3 Determination of total pore volume The total pore volume was determined according to ISO 15901-2:2006.

[0096] Preparation of catalyst A total of four catalysts were prepared, as shown in Table 1. Example 2.2 describes the preparation of a NOx adsorber DOC catalyst according to the present invention. The performance advantages of the inventive example were demonstrated over Comparative Example 2.1. Two additional Comparative Examples 1.1 and 1.2 were prepared to demonstrate the effect of the additional feature of 2 wt% barium on ceria in Comparative Example 2.1.

[0097] [Table 1]

[0098] Comparative Example 1.1: Preparation of NOx adsorbent DOC (NA-DOC) Bottom Coating: The support material (ceria to alumina in a weight ratio of 50:50 and a BET specific surface area of ​​140 m 2 A mixed oxide of Ce and Al with a pore volume of 0.7 mL / g and a pore volume of 0.7 mL / g) was impregnated by a wet impregnation process with platinum (using an aqueous solution containing an amine-stabilized hydroxo Pt(IV) complex, the solution having a Pt content between 15 wt. %) and palladium (using an aqueous solution containing Pd nitrate with a concentration ranging from 15 to 23 wt. %) in a weight ratio of 9:1, calculated as the elements, respectively.

[0099] The resulting impregnated support material, ceria, zeolitic material with framework type BEA of H type (silica to alumina molar ratio SiO2:Al2O3 is 12.5:1 and crystallinity determined by XRD is more than 80%), the amount of zirconia in the bottom coating calculated as ZrO2 is 0.05 g / in 3 and the amount of magnesium oxide in the bottom coating, calculated as MgO, is 0.05 g / in 3 A slurry containing magnesium acetate was prepared such that: A cordierite (1.9 L total volume, 400 cpsi, and 4 mil wall thickness, 143.8 mm diameter x 114.3 mm length) uncoated circular flow-through honeycomb substrate was coated with the resulting slurry from the inlet end to the outlet end of the substrate over 70% of the axial length of the substrate. The coated substrate was then dried in air at 110°C for 1 hour and calcined in air at 590°C for 2 hours. The first coating (bottom coating) had a coating yield of 76.9 g / ft 3 of platinum and 8.8g / ft 3 of palladium, 0.8 g / in 3 Ce / Al mixed oxide, 3.9g / in 3 of ceria, 0.35 g / in 3 H-BEA, 0.05g / in 3 of ZrO2, and 0.05 g / in 3 The loading of the first coating was 5.20 g / in 3 It was.

[0100] Inlet top coating: Support material (BET specific surface area 170m 2% SiO2 doped alumina, with a pore volume of 0.7 mL / g and a pore volume of 0.7 mL / g, was impregnated by a wet impregnation process with platinum (using an aqueous solution of a stabilized platinum complex) and palladium (using an aqueous solution containing Pd nitrate and having a concentration in the range of 19 wt%) in a weight ratio of 1:1, each calculated as an element, and then chemically fixed using barium hydroxide. A slurry was then prepared containing the resulting impregnated support material and a zeolitic material with framework type BEA in the H-form, with a silica to alumina molar ratio of SiO2:Al2O3 of 12.5:1 and a crystallinity of more than 80% as determined by XRD.

[0101] The bottom coating coated substrate was then coated with the resulting slurry over 50% of the axial length of the substrate from the inlet end to the outlet end of the substrate to form an inlet topcoat. The coated substrate was then dried in air at 110° C. for 1 hour and calcined in air at 590° C. for 2 hours. The inlet topcoat had a coating weight of 14.0 g / ft 3 of platinum, 14.0 g / ft 3 of palladium, 0.7 g / in 3 Si-alumina, 0.25g / in 3 of H-BEA, and 0.02g / in 3 The loading of the inlet coat was 0.97 g / in 3 It was.

[0102] Outlet top coating: Support material (BET specific surface area 120m 2 % MnO2 doped alumina, with a pore volume of 0.7 mL / g and a pore volume of 0.7 mL / g, was impregnated with platinum (using an aqueous solution of a stabilized platinum complex) and palladium (using an aqueous solution containing Pd nitrate with a concentration in the range of 19 wt%) in a weight ratio of 9:1, each calculated as the element, by a wet impregnation process, and then chemically fixed using barium hydroxide. The substrate having the bottom coating and inlet coat thereon was further coated with a slurry containing the resulting impregnated support material over 50% of the axial length of the substrate from the outlet end toward the inlet end of the substrate. The coated substrate was then dried in air at 110° C. for 1 hour and calcined in air at 590° C. for 2 hours. The outlet topcoat had a coating weight of 82.8 g / ft 3 of platinum and 9.2g / ft 3 The exit topcoat loading was 1.36 g / in 3 It was. The loading of the second coating (inlet coat + outlet coat) was about 1.16 g / in 3 It was.

[0103] Comparative Example 1.2: Preparation of Ba / Ce-containing NOx adsorbent DOC (NA-DOC) Bottom Coating: The support material (ceria to alumina in a weight ratio of 50:50 and a BET specific surface area of ​​140 m 2 A mixed oxide of Ce and Al with a pore volume of 0.7 mL / g and a pore volume of 0.7 mL / g was impregnated by a wet impregnation process with platinum (using an aqueous solution containing an amine-stabilized hydroxo Pt(IV) complex, the solution having a Pt content between 15 wt. %) and palladium (using an aqueous solution containing Pd nitrate with a concentration ranging from 15 to 23 wt. %) in a weight ratio of 9:1, calculated as the elements. The oxide material, ceria (BET specific surface area of ​​120 m 2 The Pt / Pd-impregnated support material, Ba-impregnated oxide material, and zeolitic material with framework type BEA (silica to alumina molar ratio SiO2:Al2O3 is 12.5:1 and crystallinity determined by XRD is more than 80%) were impregnated with barium acetate by a wet impregnation process such that the amount of barium in the bottom coating, calculated as ZrO2, was 2 wt% based on the weight of the oxide material (ceria), and then calcined at 590°C for 2 hours. The resulting Pt / Pd-impregnated support material, Ba-impregnated oxide material, and zeolitic material with framework type BEA (silica to alumina molar ratio SiO2:Al2O3 is 12.5:1 and crystallinity determined by XRD is more than 80%) were formed into a slurry such that the amount of zirconia in the bottom coating, calculated as ZrO2, was 0.05 g / in 3and the amount of magnesium oxide in the bottom coating, calculated as MgO, is 0.05 g / in 3 A magnesium acetate solution was prepared such that: A cordierite (1.9 L total volume, 400 cpsi, and 4 mil wall thickness, 143.8 mm diameter x 114.3 mm length) uncoated circular flow-through honeycomb substrate was coated with the resulting slurry from the inlet end to the outlet end of the substrate over 70% of the axial length of the substrate. The coated substrate was then dried in air at 110°C for 1 hour and calcined in air at 590°C for 2 hours. The first coating (bottom coating) had a saturation of 76.9 g / ft 3 of platinum and 8.8g / ft 3 of palladium, 0.8 g / in 3 Ce / Al mixed oxide, 3.9g / in 3 Ba / Ceria, 0.35 H-BEA, 0.05g / in 3 of ZrO2, and 0.05 g / in 3 The loading of the first coating was 5.20 g / in 3 It was.

[0104] Top Coating: The inlet and outlet top coatings of this example were prepared as the inlet and outlet coatings of Comparative Example 1.1 and placed on the bottom coating coated substrate in the same manner.

[0105] Comparative Example 2.1: Preparation of Ba / Ce-containing NOx adsorbent DOC (NA-DOC) Bottom Coating: The support material (ceria to alumina in a weight ratio of 50:50 and a BET specific surface area of ​​140 m 2A mixed oxide of Ce and Al with a pore volume of 0.7 mL / g and a pore volume of 0.7 mL / g) was impregnated by a wet impregnation process with platinum (using an aqueous solution containing an amine-stabilized hydroxo Pt(IV) complex, the solution having a Pt content between 15 wt. %) and palladium (using an aqueous solution containing Pd nitrate with a concentration ranging from 15 to 23 wt. %) in a weight ratio of 9:1, calculated as the elements, respectively. Next, the oxide material ceria (BET specific surface area is 120 m 2 / g) was impregnated with barium acetate by a wet impregnation process such that the amount of barium calculated as BaO was 2 wt. % based on the weight of the oxide material (ceria) and then calcined at 590 °C for 2 h. The resulting Pt / Pd-impregnated support material, Ba-impregnated oxide material, and zeolitic material having framework type BEA in its H-form (silica to alumina molar ratio SiO2:Al2O3 is 12.5:1 and the crystallinity determined by XRD is greater than 80%), the amount of zirconia in the bottom coating calculated as ZrO2 was 0.05 g / in 3 and the amount of magnesium oxide in the bottom coating, calculated as MgO, is 0.05 g / in 3 A slurry containing magnesium acetate was prepared such that: A cordierite (1.9 L total volume, 400 cpsi, and 4 mil wall thickness, 143.8 mm diameter x 114.3 mm length) uncoated circular flow-through honeycomb substrate was coated with the resulting slurry from the inlet end to the outlet end of the substrate over 100% of the axial length of the substrate. The coated substrate was then dried in air at 110°C for 1 hour and calcined in air at 590°C for 2 hours. The first coating (bottom coating) had a coating weight of 53.8 g / ft 3 of platinum and 6.2g / ft 3 of palladium, 0.8 g / in 3 Ce / Al mixed oxide, 3.9g / in 3 Ba / Ceria, 0.5 H-BEA, 0.05g / in 3 of ZrO2, and 0.05 g / in 3The loading of the first coating was 5.35 g / in 3 It was.

[0106] Inlet top coating: Support material (BET specific surface area 170m 2 % SiO2 doped alumina, with a pore volume higher than 0.7 mL / g, was impregnated with platinum (using an aqueous solution of a stabilized platinum complex) and palladium (using an aqueous solution containing Pd nitrate with a concentration ranging from 15 to 23 wt %) in a 1:1 weight ratio, each calculated as an element, by a wet impregnation process, and then chemically fixed using barium hydroxide. A slurry containing the resulting impregnated support material was then prepared. The bottom coating coated substrate was then coated with the resulting slurry over 50% of the axial length of the substrate from the inlet end towards the outlet end to form an inlet top coat. The coated substrate was then dried at 110°C in air for 1 hour and calcined at 590°C in air for 2 hours. The inlet top coat had a pore volume of 30.0 g / ft 3 of platinum, 30.0 g / ft 3 of palladium, 0.7 g / in 3 of Si-alumina, and 0.02 g / in 3 The loading of the inlet coat was 0.73 g / in 3 It was.

[0107] Outlet top coating: Support material (BET specific surface area 170m 2% SiO2 doped alumina, with a pore volume greater than 0.7 mL / g and a pore volume greater than 0.7 mL / g, was impregnated with platinum (using an aqueous solution of a stabilized platinum complex) and palladium (using an aqueous solution containing Pd nitrate with a concentration in the range of 19 wt %) in a weight ratio of 9:1, each calculated as an element, by a wet impregnation process, and then chemically fixed using barium hydroxide. The substrate with the bottom coating and inlet coat thereon was further coated with a slurry containing the resulting impregnated support material over 50% of the axial length of the substrate from the outlet end towards the inlet end of the substrate. The coated substrate was then dried at 110° C. in air for 1 hour and calcined at 590° C. in air for 2 hours. The outlet top coat had a concentration of 54.0 g / ft 3 of platinum, 6.0g / ft 3 of palladium, 1.3 g / in 3 of Si / alumina, and 0.01 g / in 3 The loading of the exit top coating was 1.36 g / in 3 It was.

[0108] Example 2.2: Preparation of Pd / Ce-containing NOx adsorbent DOC (NA-DOC) NA Coating (Inlet Bottom Coating): The support material (ceria to alumina weight ratio of 30:70, BET specific surface area of ​​170 m 2 / g Ce / Al mixed oxide with a pore volume of 0.8 mL / g) was impregnated by a wet impregnation process with platinum (using an aqueous solution containing an amine-stabilized hydroxo Pt(IV) complex, the solution having a Pt content between 15 wt. %) and palladium (using an aqueous solution containing Pd nitrate, with concentrations ranging from 15 to 23 wt. %) in a weight ratio of 9:1, calculated as the elements, respectively.

[0109] Next, the oxide material ceria (BET specific surface area is 120 m 2The Pt / Pd-impregnated support material, a ceria oxide material with a BET specific surface area of ​​120 m, was impregnated with barium acetate by a wet impregnation process such that the amount of barium, calculated as BaO, was 2 wt. % based on the weight of the oxide material (ceria), and then calcined at 590° C. for 2 hours. 2 / g), the amount of zirconia in the bottom coating, calculated as ZrO2, is 0.05 g / in 3 and the amount of magnesium oxide in the bottom coating, calculated as MgO, is 0.05 g / in 3 A slurry was formed with magnesium acetate such as:

[0110] An uncoated circular flow-through honeycomb substrate of cordierite (1.9 L total volume, 400 cpsi, and 4 mil wall thickness, 143.8 mm diameter x 114.3 mm length) was coated with the resulting slurry over 50% of the axial length of the substrate from the inlet end to the outlet end of the substrate to form an inlet bottom coating. The coated substrate was then dried in air at 110°C for 1 hour and calcined in air at 590°C for 2 hours. The inlet bottom coating had a viscosity of 53.8 g / ft 3 of platinum and 6.2g / ft 3 of palladium, 0.8 g / in 3 Ce / Al mixed oxide, 3.9g / in 3 of ceria, 0.05 g / in 3 of ZrO2, and 0.05 g / in 3 The loading of the inlet bottom coating was 4.85 g / in 3 It was.

[0111] NA Coating (Exit Bottom Coating): 120m 2An oxide material, ceria having a BET specific surface area of ​​10.0 g / ft 2, was impregnated with palladium (using an aqueous solution containing Pd nitrate with a concentration ranging from 15-23 wt %). A slurry containing the resulting impregnated oxide material was then prepared and the inlet bottom coat coated substrate was then coated over 50% of the axial length of the substrate from the outlet end towards the inlet end of the substrate. The coated substrate was then dried in air at 110°C for 1 hour and calcined in air at 590°C for 2 hours. The outlet bottom coating had a palladium content of 60.0 g / ft 2. 3 of palladium 3.90g / in 3 The loading of the exit coating was 3.93 g / in 3 It was.

[0112] DOC Coating (Top Coating): Support material (BET specific surface area 170m 2 % SiO2 doped alumina with a pore volume higher than 0.7 mL / g) was impregnated with platinum (using an aqueous solution of a stabilized platinum complex) and palladium (using an aqueous solution containing Pd nitrate with concentrations ranging from 15 to 23 wt %) in a weight ratio of 9:1, calculated as the element, by a wet impregnation process, and then chemically fixed using barium hydroxide.

[0113] The resulting impregnated support material and zeolite material with framework type BEA (silica to alumina molar ratio SiO2:Al2O3 of 26:1, crystallinity greater than 90% as determined by XRD, containing 1.4 wt. % Fe as determined by XRD and calculated as Fe2O3) were prepared and coated onto a cordierite flow-through substrate with inlet and outlet bottom coats over 100% of the axial length of the substrate from the inlet end toward the outlet end. The coated substrate was then dried at 110° C. in air for 1 hour and calcined at 590° C. in air for 2 hours. The second coating (top coating) had a molecular weight of 54.0 g / ft 3 of platinum, 6.0g / ft 3 of palladium, 1.2 g / in3 Si / alumina, 0.35 g / in 3 Fe-BEA, and 0.1 g / in 3 The loading of the second coating was about 1.70 g / in 3 It was.

[0114] Example 3: WLTC evaluation of NA-DOC of Comparative Examples 1.1, 1.2, and 2.1 and Example 2.2 in a diesel engine The catalysts of Comparative Examples 1.1, 1.2, and 2.1, and Example 2.2 were tested in a Worldwide Harmonized Light Vehicle Test Cycle (WLTC) in a 2L diesel engine after hydrothermal aging at 800°C in 10% steam (water) / air for 16 hours, followed by a sulfation and lean desulfation procedure (50 cycles). The pretreatment for the reported tests was an abbreviated WLTC with a temperature treatment at 650°C for 10 minutes to purge any pre-adsorbed NOx, and a maximum temperature of 280°C for controlled pre-loading of NOx.

[0115] FIG. 1 shows the cumulative NOx storage on the NOx adsorber DOC in the cold start region of the WLTC. All formulations adsorb NOx from the exhaust gas exiting the engine. No net desorption of NOx adsorbed during pretreatment was observed for any of the samples. Comparison of Comparative Examples 1.1 and 1.2 shows the advantage in NOx storage efficiency of adding barium to the formulation. In contrast to Comparative Example 2.1, a significant increase in NOx storage efficiency is observed despite the fact that the catalyst of Example 2.2 does not contain barium on ceria as a NOx storage material. Without wishing to be bound by any theory, it is believed that this can be attributed to the Pd / Ce feature in the outlet bottom coat of Example 2.2. Stability against sulfation and lean desulfation was also demonstrated in this procedure.

[0116] Example 4 Preparation of Pd / Ce-containing NOx adsorbent DOC (NA-DOC) Inlet bottom coating: The inlet bottom coating of Example 4 increased the platinum group metal loading to 3.9 g / in using barium hydroxide. 3 The inlet bottom coating was prepared similarly to that of Example 2.2, except that ceria was impregnated in an amount of 100 g / ft. The loading of the inlet bottom coating was therefore 63 g / ft. 3 of platinum, 7g / ft 3 of palladium, 0.8 g / in 3 Ce / Al mixed oxide, 0.08g / in 3 BaO, 3.0g / in 3 of ceria, 0.05 g / in 3 of MgO, and 0.05 g / in 3 The ZrO2 content was 4.92 g / in 3 .

[0117] Exit bottom coating: The exit bottom coating in the example has an exit bottom coat of 3.90 g / in 3 of Pd / ceria and 50.0 g / ft 3 The exit bottom coating was prepared similarly to that of Example 2.2, except that it contained 1.0 g / in of palladium. The exit bottom coating had a loading of 3.93 g / in 3 It was.

[0118] Top Coating: The top coating of Example 4 was 54.0 g / ft 3 of platinum, 6.0g / ft 3 of palladium, 1.2 g / in 3 Si / alumina, 0.5g / in 3 Fe-BEA, and 0.1 g / in 3 The top coating was prepared similarly to that of Example 2.2, except that it contained about 1.85 g / in BaO. 3 It was.

[0119] Example 5 Testing of Catalysts of Example 1.1 and Example 4 - HC and CO Light-off Temperatures The HC and CO light-off temperatures of Comparative Example 1.1 and Example 4 were measured in a 3L diesel engine after hydrothermal aging at 800°C for 16 hours in 10% steam (water) / air. The light-off temperatures were determined under the highest deactivation conditions (lean filter regeneration mode at 650°C for 10 minutes). The space velocity was approximately 30Kh -1 The concentrations were 830-1270 ppm for CO, 160-220 ppm for THC, and 40-80 ppm for NOx. The results are shown in Figures 2 and 3.

[0120] As can be seen from Figures 2 and 3, the catalyst of Example 4 has a CO T of 187°C (deactivation) at the temperature measured for the comparative example. 50 Compared to the lower temperature at which 50% of CO is converted, i.e., CO T of 167°C (deactivation), 50 This is also true for HC conversion, i.e., the catalyst of the present invention has a lower HC T at 177°C than the comparative catalyst (187°C). 70 (the temperature at which 70% of HC is converted). Thus, it was demonstrated that the catalyst of the present invention exhibits improved CO and HC oxidation performance.

[0121] Example 6: WLTC evaluation of NA-DOC of Comparative Example 1.1 and Example 4 in a diesel engine The catalysts of Comparative Example 1.1 and Example 4 were tested in a Worldwide Harmonized Light Vehicle Test Cycle (WLTC) in a 3L diesel engine after hydrothermal aging for 16 hours at 800° C. in 10% steam (water) / air. Pre-treatments for the reported tests were a 10 minute temperature treatment at 650° C. to purge any pre-adsorbed NOx, as well as a full WLTC (FIG. 4) with a maximum temperature of 350° C. and an abbreviated WLTC (FIG. 5) with a maximum temperature of 320° C. for controlled pre-loading of NOx.

[0122] Figures 4 and 5 show the cumulative NOx storage on the NOx adsorber DOC in the cold start region of the WLTC. All formulations adsorb NOx from the exhaust gas exiting the engine. No net desorption of NOx adsorbed during pretreatment was observed for any of the samples. Comparison of Comparative Example 1.1 and Example 4 shows the advantage in NOx storage efficiency of adding barium and Pd / Ce features to the formulation. From the comparison of Comparative Examples 1.1, 1.2, and 2.1 with Example 2.2, the main advantage in NOx adsorption can be attributed to the Pd / Ce feature. The different conditions in the NOx preload demonstrate the ability of the catalyst to provide NOx storage efficiency under all cold start conditions. [Brief description of the drawings]

[0123] [Figure 1] 1 shows the cumulative NOx storage of Comparative Examples 1.1, 1.2, and 2.1 and Example 2.2 catalysts in WLTC after 16 hours of steam aging at 800° C. and subsequent sulfation and lean desulfation (50 cycles). [Diagram 2] 1 shows the CO light-off temperatures (CO T50) of the catalysts of Comparative Example 1.1 and Example 4 after aging (deactivation). [Diagram 3] 1 shows the HC light-off temperatures (HC T70) of the catalysts of Comparative Example 1.1 and Example 4 after aging (deactivation). [Figure 4] 1 shows the cumulative NOx storage of Comparative Example 1.1 and Example 4 catalysts in WLTC after steam aging at 800° C. for 16 hours. [Diagram 5] 1 shows the cumulative NOx storage of Comparative Example 1.1 and Example 4 catalysts in WLTC after steam aging at 800° C. for 16 hours.

[0124] References - International Publication No. 2016 / 141142(A1) - International Publication No. 2020 / 236879(A1)

Claims

1. 1. A NOx adsorber diesel oxidation catalyst (NA-DOC) for treating exhaust gases, comprising: (i) a substrate having an inlet end, an outlet end, a substrate axial length extending from the inlet end to the outlet end, and a plurality of passages defined by an interior wall of the substrate extending therethrough; (ii) a first NOx sorbent (NA) coating, the first NA coating comprising palladium supported on a first non-zeolitic oxide material comprising ceria; (iii) a second NOx sorbent (NA) coating, the second NA coating comprising one or more of an alkaline earth metal supported on a support material and a platinum group metal component supported on a second non-zeolitic oxide material; and (iv) a diesel oxidation catalyst (DOC) coating, the DOC coating comprising a platinum group metal component supported on a third non-zeolitic oxide material; the first NA coating (ii) is disposed on the surface of the inner wall of the substrate (i) over x % of the substrate axial length from the outlet end toward the inlet end of the substrate, where x is in the range of 20 to 70; the second NA coating (iii) is disposed over y % of the substrate axial length from the inlet end toward the outlet end of the substrate, where y is in the range of 20 to 70; the DOC coating is disposed on the first NA coating and the second NA coating, or on the first NA coating, the second NA coating, and the surface of the inner wall of the substrate, over z % of the axial length of the substrate, and z is in the range of 50 to 100.

2. 2. The catalyst of claim 1, wherein 95 to 100 wt.%, preferably 98 to 100 wt.%, more preferably 99 to 100 wt.%, more preferably 99.5 to 100 wt.%, more preferably 99.9 to 100 wt.%, of the first non-zeolitic oxide material comprised in the first NA coating (ii) consists of ceria, calculated as CeO2.

3. 3. A catalyst according to claim 1 or 2, wherein the first NA coating (ii) comprises a loading of palladium, calculated as elemental Pd, in the range of from 5 to 150g / ft, preferably in the range of from 10 to 120g / ft, more preferably in the range of from 30 to 100g / ft, more preferably in the range of from 40 to 80g / ft, more preferably in the range of from 45 to 75g / ft.

4. the second NA coating (iii) comprises the platinum group metal component, wherein the platinum group metal component is one or more of Pt, Pd, Rh, Ir, Ru, and Os, preferably one or more of Pt, Pd, and Rh, more preferably one or more of Pt and Pd, more preferably Pt and Pd; the weight ratio of platinum to palladium, calculated as Pt:Pd, is preferably in the range of from 5:1 to 15:1, more preferably in the range of from 7:1 to 12:1, more preferably in the range of from 8:1 to 10:1; 3. A catalyst according to claim 1 or 2, wherein the second NA coating (iii) preferably comprises a loading of the platinum group metal component, calculated as elemental platinum group metal, in the range of from 5 to 150g / ft, more preferably in the range of from 10 to 120g / ft, more preferably in the range of from 30 to 100g / ft, more preferably in the range of from 40 to 80g / ft, more preferably in the range of from 45 to 75g / ft.

5. In the second NA coating (iii), the second non-zeolitic oxide material supporting the platinum group metal component is selected from the group consisting of ceria, alumina, zirconia, silica, titania, mixed oxides comprising one or more of Ce, Al, Zr, Si, and Ti, and mixtures of two or more thereof, preferably selected from the group consisting of ceria, alumina, and mixed oxides comprising one or more of Ce and Al, more preferably selected from the group consisting of ceria and mixed oxides comprising one or more of Ce and Al, more preferably a mixed oxide comprising Ce and Al, more preferably a mixed oxide of Ce and Al; 3. The catalyst of claim 1 or 2, wherein the weight ratio of Ce:Al, calculated as CeO2:Al2O3, is more preferably in the range of 10:90 to 90:10, more preferably in the range of 20:80 to 50:50, more preferably in the range of 25:75 to 50:

50.

6. 3. The catalyst of claim 1 or 2, wherein the second NA coating (iii) further comprises an oxide component selected from the group consisting of ceria, zirconia, alumina, silica, titania, mixed oxides comprising one or more of Ce, Zr, Al, Si, and Ti, and mixtures of two or more thereof, more preferably an oxide component selected from the group consisting of ceria, zirconia, alumina, and titania, more preferably an oxide component selected from the group consisting of ceria, zirconia, and alumina, more preferably ceria.

7. 3. The catalyst according to claim 1 or 2, wherein at most 0.01 wt.-%, preferably at most 0.001 wt.-%, more preferably at most 0.0001 wt.-% of said second NA coating consists of barium, calculated as BaO.

8. the second NA coating (iii) comprising the alkaline earth metal supported on a support material and the platinum group metal component supported on a second non-zeolitic oxide material; in said second NA coating (iii), the weight ratio of said second non-zeolitic oxide material to said support material is in the range of 0.05:1 to 0.9:1, more preferably in the range of 0.1:1 to 0.7:1, more preferably in the range of 0.15:1 to 0.5:1, more preferably in the range of 0.17:1 to 0.25:1; the alkaline earth metal is preferably selected from the group consisting of barium, strontium, calcium, and magnesium, more preferably selected from the group consisting of barium, strontium, and magnesium, more preferably barium; 3. The catalyst according to claim 1 or 2, wherein preferably the support material supporting the alkaline earth metal, more preferably barium, in the second NA coating (iii) is selected from the group consisting of ceria, zirconia, alumina, silica, titania, mixed oxides comprising one or more of Ce, Zr, Al, Si and Ti, and mixtures of two or more thereof, more preferably selected from the group consisting of ceria, zirconia, alumina and titania, more preferably selected from the group consisting of ceria, zirconia and alumina, more preferably ceria.

9. the platinum group metal component in the DOC coating (iv) is one or more of Pt, Pd, Rh, Ir, Ru, and Os, preferably one or more of Pt, Pd, and Rh, more preferably one or more of Pt and Pd, more preferably Pt and Pd; 3. The catalyst according to claim 1 or 2, wherein the weight ratio of platinum to palladium, calculated as Pt:Pd, is preferably in the range of from 2:1 to 20:1, more preferably in the range of from 5:1 to 15:1, more preferably in the range of from 7:1 to 12:1, more preferably in the range of from 8:1 to 10:

1.

10. the third non-zeolitic oxide material comprised in the DOC coating (iv) is selected from the group consisting of alumina, zirconia, silica, titania, mixed oxides comprising one or more of Al, Zr, Si, and Ti, and mixtures of two or more thereof, preferably selected from the group consisting of silica, alumina, and mixed oxides comprising one or more of Si and Al, more preferably selected from the group consisting of alumina and mixed oxides comprising one or more of Si and Al, more preferably a mixed oxide comprising Si and Al, more preferably a mixed oxide of Si and Al; 3. A catalyst according to claim 1 or 2, wherein preferably 90 to 99 wt.%, more preferably 92 to 98 wt.%, more preferably 93 to 97 wt.% of the second non-zeolitic material in the DOC coating (iv) consists of alumina and preferably 1 to 10 wt.%, more preferably 2 to 8 wt.%, more preferably 3 to 7 wt.% of the DOC coating (iv) consists of silica.

11. the DOC coating (iv) further comprises a zeolitic material comprising one or more of iron and copper, preferably an iron-containing zeolitic material; the DOC coating (iii) comprises an amount of iron, calculated as Fe2O3, in the range of 0.25 to 4 wt. %, more preferably in the range of 0.5 to 3 wt. %, more preferably in the range of 0.75 to 2.5 wt. %, based on the weight of the iron-containing zeolitic material contained in the DOC coating (iv); or the DOC coating (iv) further comprises a zeolite material in the H and / or NH form; 3. A catalyst according to claim 1 or 2, wherein the zeolitic material comprised in the DOC coating (iv) is preferably a 12-ring pore zeolitic material, the zeolitic material more preferably having a framework type selected from the group consisting of BEA, MOR, FAU, GME, OFF, mixtures of two or more thereof, and mixed types of two or more thereof, more preferably a framework type selected from the group consisting of BEA, MOR, FAU, mixtures of two or more thereof, and mixed types of two or more thereof, more preferably a framework type selected from the group consisting of BEA and FAU, more preferably the 12-ring pore zeolitic material comprised in the DOC coating (iv) has framework type BEA.

12. A process for preparing the NOx adsorbent diesel oxidation catalyst (NA-DOC) of claim 1 or 2, comprising: (a) preparing a first mixture comprising water, a palladium source, and a first non-zeolitic oxide material comprising ceria; (b) disposing the first mixture obtained according to (a) on a surface of an inner wall of a substrate having an inlet end, an outlet end, a substrate axial length extending from the inlet end to the outlet end, and a plurality of passages defined by the inner wall of the substrate extending therethrough, over x % of the substrate axial length from the outlet end toward the inlet end of the substrate, where x is in the range of 20 to 70, and calcining to obtain a substrate having a first NOx sorbent (NA) coating thereon; (c) preparing a second mixture comprising water and a source of one or more of said alkaline earth metals having a support material for said alkaline earth metals and said platinum group metal component having a second non-zeolitic oxide material for supporting said platinum group metal component; (d) disposing the second mixture obtained according to (c) onto the substrate having the first NA coating thereon over y% of the substrate axial length from the inlet end toward the outlet end of the substrate, where y is in the range of 20 to 70, and calcining to obtain a substrate having a first NA coating and a second NA coating; (e) preparing a third mixture comprising water, a source of a platinum group metal component, and a third non-zeolitic oxide material; (f) disposing the third mixture obtained according to (e) on the substrate having the first NA coating and the second NA coating thereon over z % of the substrate axial length, where z is in the range of 50 to 100; (g) calcining the substrate obtained according to (f) to obtain a substrate having thereon a first NA coating, a second NA coating, and a DOC coating.

13. A NOx adsorbent diesel oxidation catalyst (NA-DOC) obtained or obtainable by the process of claim 12.

14. Use of the NOx adsorbent diesel oxidation catalyst (NA-DOC) according to claim 1 or 2 for the adsorption / desorption of NOx and the conversion of HC and CO.

15. 1. An exhaust treatment system for treating exhaust gases, comprising:

3. A NOx adsorber diesel oxidation (NA-DOC) catalyst according to claim 1 or 2, Preferably, the exhaust treatment system further comprises one or more of a selective catalytic reduction (SCR) catalyst, a selective catalytic reduction on a filter (SCRoF) catalyst, and an ammonia oxidation (AMOX) catalyst.

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