TETRA-FUNCTIONAL CATALYST FOR THE OXIDATION OF NO, THE OXIDATION OF A HYDROCARBON, THE OXIDATION OF NH3 AND THE SELECTIVE CATALYTIC REDUCTION OF NOx

Abstract

The present invention relates to a catalyst, preferably for the selective catalytic reduction of NOx, for the oxidation of ammonia, for the oxidation of NO and for the oxidation of a hydrocarbon, the catalyst comprising a washcoat comprising one or more layers, the washcoat being disposed on a substrate, wherein the washcoat comprises a platinum group metal supported on a metal oxide support material, and one or more of an oxidic compound of V, an oxidic compound of W and a zeolitic material comprising one or more of Cu and Fe.

Claims

1. A catalyst comprising a washcoat comprising one or more layers, the washcoat being disposed on a substrate, wherein the washcoat comprises (i) a platinum group metal supported on a metal oxide support material, and (ii) at least one selected from the group consisting of an oxidic compound of V, an oxidic compound of W, and a zeolitic material comprising one or more of Cu and Fe.

2. The catalyst of claim 1 wherein the washcoat comprises (i) a platinum group metal supported on a metal oxide support material, and (ii) a zeolitic material comprising one or more of Cu and Fe.

3. The catalyst of claim 1, wherein the platinum group metal is at least one selected from the group consisting of Pt, Pd and Rh.

4. The catalyst of claim 1, wherein the framework structure of the zeolitic material comprises a tetravalent element Y which is at least one selected from the group consisting of Si, Sn, Ti, Zr and Ge.

5. The catalyst of claim 1, wherein the zeolitic material has a framework structure of the type AEI, GME, BEA, CHA, FAU, FER, HEU, LEV, MEI, MEL, MFI, or MOR.

6. The catalyst of claim 1, wherein the zeolitic material comprises Cu.

7. The catalyst of claim 1, wherein the substrate has a plurality of longitudinally extending passages formed by longitudinally extending walls bounding and defining the passages and a longitudinal total length extending between a front end and a rear end of the substrate.

8. The catalyst of claim 1, wherein the washcoat consists of one layer.

9. The catalyst of claim 8, wherein the substrate has a substrate length and wherein the one layer is disposed on 50 to 100% of the total length of the substrate.

10. The catalyst of claim 1, wherein the washcoat comprises a first and a second layer, wherein the first layer comprises at least one selected from the group consisting of the oxidic compound of V, the oxidic compound of W, and the zeolitic material comprising one or more of Cu and Fe, and wherein the second layer comprises the platinum group metal supported on the metal oxide support material.

11. The catalyst of claim 10, wherein the first layer is disposed on the substrate and the second layer is at least partially disposed on the first layer, or wherein the second layer is disposed on the substrate and the first layer is at least partially disposed on the second layer.

12. The catalyst of claim 10, wherein the washcoat further comprises a third layer.

13. A process, comprising performing simultaneous selective catalytic reduction of NOx, the oxidation of ammonia, the oxidation of nitrogen monoxide and the oxidation of a hydrocarbon, with the catalyst of claim 1.

14. An exhaust gas treatment system, comprising the catalyst of claim 1.

15. The exhaust gas treatment system of claim 14, additionally comprising a catalyzed soot filter, wherein the catalyst of claim 1 is located upstream of the catalyzed soot filter, and wherein no diesel oxidation catalyst is located between the catalyst and the catalyzed soot filter.

16. The exhaust gas treatment system of claim 14, comprising a first reductant injector, a first catalyst for the selective catalytic reduction of NO.sub.x, a second catalyst, wherein said second catalyst is the catalyst of claim 1; a catalyzed soot filter, a second reductant injector, a third catalyst for the selective catalytic reduction of NO.sub.x, and a fourth catalyst for the selective catalytic reduction of NO.sub.x and/or for the oxidation of ammonia.

17. A process for preparing the catalyst of claim 1, comprising disposing one or more slurries on a substrate, the one or more slurries comprising the platinum group metal supported on a metal oxide support material and at least one selected from the group consisting of the oxidic compound of V, the oxidic compound of W and the zeolitic material comprising one or more of Cu and Fe, wherein, after having disposed a slurry on the substrate, a slurry-treated substrate is obtained which is dried and calcined.

Description

EXAMPLES

Reference Example 1: Determination of the D90 Values

[0284] The D90 particle size as referred to in the context of the present invention was measured with a Sympatec Particle Size instrument using laser diffraction (Sympatec's HELOS system allowing the determination of the particle size distribution in the range of from 0.1 to 8,750 micrometer). According to this method, the particle size distribution was evaluated with a parameter-free and model-independent mathematical algorithm, accomplished by the introduction of the Phillips-Twomey algorithm for the inversion process.

Reference Example 2: Preparation of a CuCHA Zeolite

[0285] The zeolitic material having the framework structure type CHA comprising Cu and used in the examples herein was prepared according to the teaching of U.S. Pat. No. 8,293,199 B2. Particular reference is made to Inventive Example 2 of U.S. Pat. No. 8,293,199 B2, column 15, lines 26 to 52.

Example 1: Preparation of a Catalyst Comprising One Washcoat Layer

[0286] A solution of a platinum precursor with platinum as an ammine stabilized hydroxo Pt(IV) complex (Pt content between 10 and 20 weight-%) was added dropwise into 0.25 g/in.sup.3 zirconia-alumina (alumina doped with 20 weight-% zirconia, Puralox SBa-200 Zr20, Sasol) under constant stirring, thereby performing an incipient wetness impregnation. The amount of liquids added was suitably calculated to fill the pore volume of the zirconia-alumina. The final solid content after incipient wetness was approximately 75 weight-%. The resulting mixture after incipient wetness impregnation was pre-calcined at 590 C. for four hours to remove any moisture and to fix the platinum onto the metal oxide support material giving a dry platinum content of 5 g/ft.sup.3.

[0287] Separately, 0.08 g/in.sup.3 (calculated as ZrO.sub.2) zirconyl-acetate solution with between 29.5 and 30 weight-% solids were added to water to create a mixture with a solid content of approximately 10 weight-%. To this, 1.66 g/in.sup.3 of the CuCHA zeolite prepared according to Reference Example 2 herein were added. The resulting slurry was then milled until the resulting D90 particle size determined as described in Reference Example 1 herein was between 3.5 micrometer and 6 micrometer in diameter. Subsequently, the pre-calcined Pt impregnated zirconia-alumina was made into a slurry. Firstly, tartaric acid in a ratio of five times the amount of Pt remaining after pre-calcination was added to water as was monoethanolamine in a ratio of 1/10 of the amount of tartaric acid. Secondly, the Pt impregnated zirconia-alumina was added to this solution and mixed into the solution thereby forming a slurry. The slurry was then milled until the D90 particle size determined as described in Reference Example 1 herein was between 9 micrometer and 11 micrometer in diameter. To this slurry, the direct exchanged CuCHA zeolite slurry was added and mixed, creating the final slurry that is ready for disposal. The final slurry was then disposed over the full length of honeycomb cordierite monolith substrates (10.53 cylindrically shaped substrate with 300 cells per square inch and 5 mil wall thickness). Afterwards, the substrates were dried to remove between 85 and 95% of moisture and were then calcined at 450 C. The total dry gain after calcination was 2.0 g/in.sup.3.

Example 2: Preparation of a Catalyst Comprising One Washcoat Layer

[0288] The procedure according to Example 1 was repeated with the exception that 0.25 g/in.sup.3 titania was used instead of zirconia-alumina. The total dry gain after calcination was 2.0 g/in.sup.3.

Example 3: Preparation of a Catalyst Comprising One Washcoat Layer

[0289] The procedure according to Example 1 was repeated with the exception that 1.0 g/in.sup.3 instead of 0.25 g/in.sup.3 zirconia-alumina (alumina doped with 20 weight-% zirconia, Puralox SBa-200 Zr20, Sasol) was used. The total dry gain after calcination was 2.75 g/in.sup.3.

Example 4: Preparation of a Catalyst Comprising Two Washcoat Layers

[0290] For the first layer (bottom layer), 0.08 g/in.sup.3 zirconyl-acetate solution with between 29.5 and 30 weight-% solids were added to water to create a mixture with a solid content of approximately 10 weight-%. To this, 1.66 g/in.sup.3 of the CuCHA zeolite prepared according to Reference Example 2 herein were added. The resulting slurry was then milled until the resulting D90 particle size determined as described in Reference Example 1 herein was between 9 micrometer and 12 micrometer in diameter. The slurry was then disposed over the full length of honeycomb cordierite monolith substrates (10.53 cylindrically shaped substrate with 300 cells per square inch and 5 mil wall thickness). Afterwards, the substrates were dried to remove between 85 and 95% of moisture and were then calcined at 450 C. The total dry gain of the first layer after calcination was 1.75 g/in.sup.3.

[0291] For the second layer (top layer), a solution of a platinum precursor with platinum as an ammine stabilized hydroxo Pt(IV) complex was diluted by 20% and then added drop wise into 0.5 g/in.sup.3 silica-alumina (alumina doped with 1.5 weight-% silica, Siralox 1.5/100, Sasol) under constant stirring, thereby performing an incipient wetness impregnation. The amount of liquids added was suitably calculated to fill the pore volume of the silica-alumina. To this incipient wetness impregnation mixture, acetic acid in the amount of 9 weight-% of the intended total dry gain of the top coat and additional water was added. The final solid content after incipient wetness impregnation was approximately 70 weight-%. Water was then added to the mixture along with n-octanol based on 0.2% of the intended dry gain of the top coat. The solid content after this step was between 43 and 47 weight-%. The slurry was then milled until the D90 particle size determined as described in Reference Example 1 herein was between 6 micrometer and 9 micrometer in diameter. The slurry was then disposed from the rear end of the honeycomb monolith substrate to 50% of the length of the substrate to form the top layer giving a dry platinum content of 10 g/ft.sup.3 for the corresponding layer (corresponding to a Pt content of 5 g/ft.sup.3 relative to the substrate in total). The substrate was then dried to remove 85 to 95% of the moisture and was then calcined at 450 C. The total dry gain of the second layer after calcination was 0.51 g/in.sup.3.

Example 5: Preparation of a Catalyst Comprising Three Washcoat Layers

[0292] For the Pt-based second layer (bottom layer), a solution of a platinum precursor with platinum as an ammine stabilized hydroxo Pt(IV) complex was diluted by 20% and then added drop wise into 1.0 g/in.sup.3 silica-alumina (alumina doped with 1.5 weight-% silica, Siralox 1.5/100, Sasol) under constant stirring, thereby performing an incipient wetness impregnation. The amount of liquids added was suitably calculated to fill the pore volume of the silica-alumina. To this incipient wetness impregnation mixture, acetic acid in the amount of 9 weight-% of the intended total dry gain of the second layer and additional water was added. The final solid content after incipient wetness was approximately 70 weight-%. Water was then added to the mixture along with n-octanol based on 0.2% of the intended dry gain of the second layer. The solid content after this step was between 43 and 47 weight-%. The slurry was then milled until the D90 particle size determined as described in Reference Example 1 was between 6 micrometer and 9 micrometer in diameter. The Pt-containing second layer slurry was then disposed from the rear end of a honeycomb cordierite monolith substrates (10.53 cylindrically shaped substrate with 300 cells per square inch and 5 mil wall thickness) to 50% of the length of the substrate giving a dry platinum content of 10 g/ft.sup.3 for the corresponding layer (corresponding to a Pt content of 5 g/ft.sup.3 relative to the substrate in total). The substrate was then dried to remove 85 to 95% of the moisture and then calcined at 450 C.

[0293] Afterwards, a zeolite slurry was produced. Zirconylacetate solution with between 29.5 and 30 weight-% solids (quantity calculated as 1/20 of the zeolite amount (dry/dry basis)) was added to water to create a mixture with a solid content of approximately 10 weight-%. To this, 1.66 g/in.sup.3 of the CuCHA zeolite prepared according to Reference Example 2 herein were added. The resulting slurry was then milled until the D90 particle size determined as described in Reference Example 1 was between 9 micrometer and 12 micrometer in diameter. To form the first layer, the zeolite slurry was disposed on 50% of the length of the honeycomb cordierite monolith substrates, on which the second layer was already disposed, from the front end of the substrate. The dry gain of the first layer was 1.75 g/in.sup.3. Afterwards, the substrates were dried to remove between 85 and 95% of moisture and were then calcined at 450 C.

[0294] Lastly, the zeolite slurry was again used to coat the third layer (outer top coat). The slurry was disposed on a length of 50% of the length of the honeycomb monolith substrates from the rear end of the substrate. The dry gain of the third layer was 0.5 g/in.sup.3. Afterwards, the substrates were dried to remove 85 to 95% of the moisture and then calcined at 450 C.

[0295] The total dry gain after calcination was 1.01 g/in.sup.3.

Example 6: Preparation of a Catalyst Comprising One Washcoat Layer

[0296] The procedure according to Example 1 was repeated with the exception that 0.5 g/in.sup.3 instead of 0.25 g/in.sup.3 zirconia-alumina zirconia-alumina was used. The total dry gain after calcination was 2.25 g/in.sup.3.

Example 7: Preparation of a Catalyst Comprising Two Washcoat Layers

[0297] For the first layer (bottom layer), a solution of a platinum precursor with platinum as an ammine stabilized hydroxo Pt(IV) complex was diluted by 20% and then added drop wise into 0.5 g/in.sup.3 silica-alumina (alumina doped with 1.5 weight-% silica, Siralox 1.5/100, Sasol) under constant stirring, thereby performing an incipient wetness impregnation. The amount of liquids added was suitably calculated to fill the pore volume of the silica-alumina. To this incipient wetness impregnation mixture, acetic acid in the amount of 9 weight-% of the intended total dry gain of the bottom coat and additional water was added. The final solid content after incipient wetness impregnation was approximately 70 weight-%. Water was then added to the mixture along with n-octanol based on 0.2% of the intended dry gain of the bottom coat. The solid content after this step was between 43 and 47 weight-%. The slurry was then milled until the D90 particle size determined as described in Reference Example 1 herein was between 6 micrometer and 9 micrometer in diameter. The slurry was then disposed from the rear end of the honeycomb monolith substrate (10.53 cylindrically shaped substrate with 300 cells per square inch and 5 mil wall thickness) to 100% of the length of the substrate to form the bottom layer giving a dry platinum content of 16 g/ft.sup.3 for the corresponding layer (corresponding to a Pt content of 8 g/ft.sup.3 relative to the substrate in total). The substrate was then dried to remove 85 to 95% of the moisture and was then calcined at 450 C. The total dry gain of the first layer after calcination was 0.51 g/in.sup.3.

[0298] For the second layer (top layer), 0.17 g/in.sup.3 zirconyl-acetate solution with between 29.5 and 30 weight-% solids were added to water to create a mixture with a solid content of approximately 10 weight-%. To this, 3.33 g/in.sup.3 of the CuCHA zeolite prepared according to Reference Example 2 herein were added. The resulting slurry was then milled until the resulting D90 particle size determined as described in Reference Example 1 herein was between 9 micrometer and 12 micrometer in diameter. The slurry was then disposed over the full length (i. e. 100% of the length of the substrate) of honeycomb cordierite monolith substrates. Afterwards, the substrates were dried to remove between 85 and 95% of moisture and were then calcined at 450 C. The total dry gain of the second layer after calcination was 3.5 g/in.sup.3.

[0299] The total dry gain of the final product was 4.0 g/in.sup.3.

Example 8: Preparation of a Catalyst Comprising One Washcoat Layer

[0300] A solution of a platinum precursor with platinum as an ammine stabilized hydroxo Pt(IV) complex (Pt content between 10 and 20 weight-%, produced internally by BASF) was added dropwise into 0.25 g/in.sup.3 zirconia-alumina (alumina doped with 20 weight-% zirconia, Puralox SBa-200 Zr20, Sasol) under constant stirring, thereby performing an incipient wetness impregnation. The amount of liquids added was suitably calculated to fill the pore volume of the zirconia-alumina. The final solid content after incipient wetness was approximately 75 weight-%. The resulting mixture after incipient wetness impregnation was pre-calcined at 590 C. for four hours to remove any moisture and to fix the platinum onto the metal oxide support material giving a dry platinum content of 8 g/ft.sup.3. Separately, 0.08 g/in.sup.3 (calculated as ZrO.sub.2) zirconyl-acetate solution with between 29.5 and 30 weight-% solids were added to water to create a mixture with a solid content of approximately 10 weight-%. To this, 3.33 g/in.sup.3 of the CuCHA zeolite prepared according to Reference Example 2 herein were added. The resulting slurry was then milled until the resulting D90 particle size determined as described in Reference Example 1 herein was between 3.5 micrometer and 6 micrometer in diameter. Subsequently, the pre-calcined Pt impregnated zirconia-alumina was made into a slurry. Firstly, tartaric acid in a ratio of five times the amount of Pt remaining after pre-calcination was added to water as was monoethanolamine in a ratio of 1/10 of the amount of tartaric acid. Secondly, the Pt impregnated zirconia-alumina was added to this solution and mixed into the solution creating a slurry. The slurry was then milled until the D90 particle size determined as described in Reference Example 1 herein was between 9 micrometer and 11 micrometer in diameter. To this slurry, the direct exchanged CuCHA zeolite slurry was added and mixed, creating the final slurry that is ready for disposal. The final slurry was then disposed over the full length of honeycomb cordierite monolith substrates (10.53 cylindrically shaped substrate with 400 cells per square inch and 4 mil wall thickness). Afterwards, the substrates were dried to remove between 85 and 95% of moisture and were then calcined at 450 C. The total dry gain after calcination was 3.75 g/in.sup.3.

Example 9: Use of the Catalysts of Examples 1 to 6NO.SUB.2 .Make

[0301] The catalysts were tested in a Diesel System Simulator capable of emulating the transients experienced by a catalyst downstream of a combustion engine. The tests were carried out under steady-state condition. The dimensions of the cores were 1(diameter)3 (length). All gas composition measurements were carried out on a FTIR spectrometer. The tests for measuring the NO.sub.2 make were carried out under NO.sub.x only conditions, this means that no ammonia was added. The catalysts of Examples 1 to 6 were tested using a gas characterized by the contents as shown below. The space velocity for each test run was set at 100,000 h.sup.1. According to the present invention the space velocity is understood as the number of volumes of exhaust gas equal to the volume of the coated catalyst that are passed through it every hour. The space velocity is a means to eliminate any influences of the catalyst size when making performance comparisons. The space velocity is calculated by the gas volumetric flow [m.sup.3/h] per catalyst volume [m.sup.3] and is accordingly expressed in the unit [1/h]. Thus, the NO.sub.2/NO.sub.x ratio was determined relative to the temperature of the gas, whereby the amount of NO.sub.x equals the sum of the amounts of NO and NO.sub.2. The resulting curve represents the light-off curve. The light-off curve was measured between 150 and 450 C. for each of the catalysts of Examples 1 to 6, whereby a ramp rate (for both ramp up and ramp down) of 10 K/min was set. At first, the light-off curve was measured when heating up (ramp up). Then, the temperature was held at 450 C. for 10 min. After that, the light-off curve was measured when cooling down (ramp down).

TABLE-US-00001 TABLE 1 Characteristics of the used gas Hydrocarbons CO NO O.sub.2 H.sub.2O CO.sub.2 [ppm] [ppm] [ppm] [%] [%] [%] 31 9 631 10 8 8

[0302] The results for the light-off are shown in FIGS. 1 and 2, samples 1 to 6 refer to Examples 1 to 6, respectively. FIG. 1 shows the light-off curve for ramp up. As can be taken from FIG. 1, it has been found that the catalyst of Example 1 according to the present invention (see sample 1) shows the highest NO.sub.2/NO.sub.x ratio in the temperature range of from 250 to 425 C. and the catalyst of Example 4 (see sample 4) in the temperature range of from 175 to 215 C. FIG. 2 shows the light-off curve for ramp down, samples 1 to 6 refer to Examples 1 to 6, respectively. As can be taken from FIG. 2, the catalyst of Example 4 (see sample 4) shows the highest NO.sub.2/NO.sub.x ratio in the temperature range of from 290 to 450 C., the catalyst of Example 5 (see sample 5) in the temperature range of from 240 to 265 C. and the catalyst of Example 1 (see sample 1) below 230 C.

Example 10: Use of the Catalysts of Examples 1 to 6Ammonia Oxidation, N.SUB.2.O Make, and NO.SUB.x .Make

[0303] In order to determine the ammonia oxidation efficiency, the N.sub.2O make and the NOx make of the catalysts of Examples 1 to 6, the ammonia slip, the N.sub.2O make, and the NOx make, respectively, were measured at steady state points. Eight steady state points have been chosen to balance temperature range and test expediency. The temperature range of 200 to 450 C. is considered most relevant for heavy duty diesel operations. The concentrations of the gases were considered to represent potential concentrations to be encountered by an AMOx in operation. NO.sub.x would typically contain only NO and much less than engine-out due to the effect of an SCR catalyst located upstream. If running at over-dosing conditions (i. e. more reductant is in the gas stream than NO.sub.x), there would be an excess of NH.sub.3 entering the AMOx compared to NO.sub.x. The O.sub.2 and H.sub.2O concentrations are considered to be consistent with typical diesel engine operations. Also, the given space velocity was considered to fit to a typical Euro VI AMOx volume. The characteristics of the eight steady state points are shown in table 1 below. The space velocity was set at 120,000 h.sup.1.

TABLE-US-00002 TABLE 2 Characteristics of the steady state points measurements Steady NH.sub.3 NO O.sub.2 H.sub.2O state Duration Temperature conc. conc. conc. conc. point [min] [ C.] [ppm] [ppm] [vol-%] [vol-%] 5 450 0 0 10 5 1 15 450 150 50 10 5 2 15 400 150 50 10 5 3 15 350 150 50 10 5 4 15 325 150 50 10 5 5 15 300 150 50 10 5 6 20 275 150 50 10 5 7 30 250 150 50 10 5 8 30 200 150 50 10 5

[0304] Ammonia Oxidation

[0305] The results of the ammonia slip measurements are displayed in FIG. 3, wherein samples 1 to 6 refer to Examples 1 to 6, respectively. FIG. 3 shows the ammonia slip relative to every single steady state point. Thus, it has been found out that the catalyst of Example 1 (see sample 1) displays the lowest ammonia slip of all Examples for each steady state point.

[0306] N.sub.2O Make

[0307] The results of the N.sub.2O make measurements are displayed in FIG. 4, wherein samples 1 to 6 refer to Examples 1 to 6, respectively. FIG. 4 shows the N.sub.2O make relative to every single steady state point. Surprisingly, the catalyst of Example 2 (see sample 2) displays the lowest N.sub.2O selectivity of all catalysts on average, in particular said catalyst displays the lowest N.sub.2O make at steady state points 2 to 7. At steady state point 8, the catalyst of Example 1 (see sample 1) shows the lowest N.sub.2O make.

[0308] NO.sub.x Make

[0309] The results of the NO.sub.x make are displayed in FIG. 5, wherein samples 1 to 6 refer to Examples 1 to 6, respectively. FIG. 5 shows the NO.sub.x make relative to every single steady state point. Thus, it has surprisingly been found out that the catalyst of Example 2 (see sample 2) displays the lowest NO.sub.x make at steady state points 1 to 6, whereas the catalyst of Example 1 (see sample 1) displays the lowest NOx make at steady state points 7 and 8.

Example 11: Use of the Catalysts of Examples 1 to 6DeNO.SUB.x .Performance, NO.SUB.x .Slip, NH.SUB.3 .Slip, NO.SUB.2 .Make

[0310] For measuring the DeNO.sub.x performance, the NOx slip, the ammonia slip and the NO.sub.2 make, the relative amount of reduced NOx was determined at five different steady state points. Similar to the AMOx test, the five steady state points were chosen to balance the most relevant temperatures for SCR with test expediency. Between 250 and 400 C., nearly all SCR catalysts are very active such that measurements at these temperatures would not give as much information.

[0311] From 175 C. to 250 C., the NO-only activity of an SCR catalyst is greatly stressed while above 400 C., the extent of NH.sub.3 oxidation can be observed, though this reaction becomes more noticeable at higher temperatures (i. e. higher than 400 C.). However, temperatures higher than 400 C. are rarely encountered in typical operation. It is considered that the NH.sub.3 adsorption capacity of the catalyst is much higher at lower temperatures and that it takes therefore longer to equilibrate and reach maximum conversion. Accordingly, the lower temperatures are held for much longer than higher temperatures. As far as the gas composition concerns, these are values that can represent European motor calibrations with overdosing. (It is noted that the NO concentration here is much higher than for the AMOx test as this is a test for SCR conversion, not for oxidation of NO or NH.sub.3.)

[0312] The temperature and duration for each steady state point is given in Table 3 below as well as the characteristics of the used gas. The space velocity was set at 62,000 h.sup.1.

TABLE-US-00003 TABLE 3 Characteristics of the DeNO.sub.x measurements NH.sub.3 NO O.sub.2 H.sub.2O CO.sub.2 Steady state Duration Temperature conc. conc. conc. conc. conc. point [min] [ C.] [ppm] [ppm] [vol-%] [vol-%] [vol-%] 1 60 175 550 500 10 5 5 2 60 200 550 500 10 5 5 3 30 225 550 500 10 5 5 4 20 250 550 500 10 5 5 5 15 400 550 500 10 5 5

[0313] DeNO.sub.x Performance

[0314] The results for the DeNO.sub.x performance are shown in FIG. 6, wherein samples 1 to 6 refer to Examples 1 to 6, respectively. As can be taken from FIG. 6, the catalyst of Example 1 (see sample 1) surprisingly shows the best DeNO.sub.x performance at steady state points 1, 2 and 3, whereas the catalyst of Example 4 (see sample 4) shows the best DeNO.sub.x performance at steady state point 4 and the catalyst of Example 5 (see sample 5) at steady state point 5.

[0315] NO.sub.x Slip

[0316] Further, the NOx slip has been determined. The results of the respective measurements are displayed in FIG. 7, wherein samples 1 to 6 refer to Examples 1 to 6, respectively. FIG. 7 shows the NOx slip relative to every single steady state point. As can be seen in FIG. 7, the catalyst of Example 1 (see sample 1) displays the lowest NO.sub.x slip at steady state points 1, 2 and 3, whereas the catalyst of Example 4 (see sample 4) displays the lowest NO.sub.x slip at steady state point 4 and the catalyst of Example 5 (see sample 5) at steady state point 5.

[0317] Ammonia Slip

[0318] In addition to that, the ammonia slip has been determined. The results are displayed in FIG. 8, wherein samples 1 to 6 refer to Examples 1 to 6, respectively. FIG. 8 shows the ammonia slip relative to every single steady state point. Therein, it can be seen that the catalyst of Example 1 (see sample 1) shows the lowest ammonia slip at steady state points 1 to 4, whereas the ammonia slip at steady state point 5 is almost similar for all catalysts. It was figured out that the catalyst of Example 1 (see sample 1) oxidizes about 22 ppm ammonia at 220 C., about 55 ppm at 225 C. and about 90 ppm at 250 C. In comparison to that, the catalyst of Example 5 (see sample 5) oxidizes about 22 ppm ammonia at 200 C., about 30 ppm at 225 C. and 65 ppm at 250 C.

[0319] NO.sub.2 Make

[0320] Further, the NO.sub.2 make has been determined. The results of the respective measurements are displayed in FIG. 9, wherein samples 1 to 6 refer to Examples 1 to 6, respectively. FIG. 9 shows the NO.sub.2 make relative to every single steady state point. It can be seen that the NO.sub.2 levels are generally very low. Further, it can be seen that the catalyst of Example 1 (see sample 1) shows the highest NO.sub.2 make at steady state points 4 and 5, whereas the NO.sub.2 make at steady state points 1 to 3 are almost similar for all catalysts.

Example 12: Use of the Catalyst of Examples 7 and 8 for Influencing the NO.SUB.2 .to NO.SUB.x .Ratio

[0321] The catalysts of Examples 7 and 8 were tested on a EU VI non-EGR 13L diesel combustion engine on a test cell. The tests were carried out under steady-state condition. A urea doser was located downstream of the engine followed by the exhaust gas aftertreatment in a cone piping set-up. Seven steady state points have been chosen to balance temperature range and test expediency. The characteristics of the seven steady state points which are designated as Loadpoints (LP1 to LP7) are shown in table 4 below.

TABLE-US-00004 TABLE 4 Characteristics of the seven steady state points measurements Exhaust mass NO.sub.x levels Temperature Loadpoint flow [kg/h] [ppm] [ C.] LP1 1960 690 467 LP2 1090 1092 450 LP3 1062 551 350 LP4 1078 225 240 LP5 600 664 367 LP6 591 429 250 LP7 591 392 217

[0322] All gas composition measurements were carried out on a FTIR spectrometer. The tests for evaluating the NO.sub.2 to NO.sub.x ratio were carried out under two different conditions with respect to the ammonia to nitrogen ratio (NSR) being (1) a NSR of 0 and (2) a NSR of 0.5.

[0323] Thus, the NO.sub.2 to NO.sub.x ratio was determined relative to each steady state point, whereby the amount of NOx equals the sum of the amounts of NO and NO.sub.2. The results of the measurements are shown in FIGS. 10 and 11, wherein in both Figures the Layered AMOx design 8 g/ft.sup.3 refers to Example 7 and the Mixed AMOx design 8 g/ft.sup.3 refers to Example 8. It can be taken from FIG. 10 that the catalyst of Example 8 (Mixed AMOx 8 g/in.sup.3) shows a higher NO.sub.2 to NO.sub.x ratio for steady state points LP1, LP2, LP3, LPS, LP6 and LP7 compared to Example 7 (Layered AMOx 8 g/in.sup.3) when applying an ammonia to nitrogen ratio (NSR) of 0. At steady state point LP4, the catalyst of Example 7 shows a higher NO.sub.2 to NOx ratio. Further, it can be taken from FIG. 11 that the catalyst of Example 8 shows a higher NO.sub.2 to NO.sub.x ratio for steady state points LP1, LP2, LP3, LPS, LP6 and LP7 compared to Example 7 (Layered AMOx 8 g/in.sup.3) when applying an ammonia to nitrogen ratio (NSR) of 0.5.

BRIEF DESCRIPTION OF FIGURES

[0324] FIG. 1: shows the light-off curve of samples 1 to 6 when heating the sample up (light-off curve for ramp up). The samples 1 to 6 refer to the catalysts of Examples 1 to 6, respectively. In the figure, the temperature is shown along the abscissa and the NO.sub.2/NO.sub.x ratio is shown along the ordinate.

[0325] FIG. 2: shows the light-off curve of samples 1 to 6 when cooling the sample down (light-off curve for ramp down). The samples 1 to 6 refer to the catalysts of Examples 1 to 6, respectively. In the figure, the temperature is shown along the abscissa and the NO.sub.2/NO.sub.x ratio is shown along the ordinate.

[0326] FIG. 3: shows the ammonia slip of samples 1 to 6 for each of the eight steady state points. The samples 1 to 6 refer to the catalysts of Examples 1 to 6, respectively. In the figure, the ammonia slip is shown on the ordinate relative to each of the eight steady state points for samples 1 to 6 shown on the abscissa.

[0327] FIG. 4: shows the N.sub.2O make of samples 1 to 6 for each of the eight steady state points. The samples 1 to 6 refer to the catalysts of Examples 1 to 6, respectively. In the figure, the N.sub.2O make is shown on the ordinate relative to each of the eight steady state points for samples 1 to 6 shown on the abscissa.

[0328] FIG. 5: shows the NO.sub.x make for samples 1 to 6 for each of the eight steady state points. The samples 1 to 6 refer to the catalysts of Examples 1 to 6, respectively. In the figure, the NO.sub.x make is shown on the ordinate relative to each of the eight steady state points for samples 1 to 6 shown on the abscissa.

[0329] FIG. 6: shows the DeNO.sub.x performance of samples 1 to 6 for each of the five steady state points. The samples 1 to 6 refer to the catalysts of Examples 1 to 6, respectively. In the figure, the relative amount of reduced NO.sub.x is shown on the ordinate relative to each of the five steady state points for samples 1 to 6 shown on the abscissa.

[0330] FIG. 7: shows the NOx slip of samples 1 to 6 for each of the five steady state points. The samples 1 to 6 refer to the catalysts of Examples 1 to 6, respectively. In the figure, the NO.sub.x slip is shown on the ordinate relative to each of the five steady state points for samples 1 to 6 shown on the abscissa.

[0331] FIG. 8: shows the ammonia slip of samples 1 to 6 for each of the five steady state points. The samples 1 to 6 refer to the catalysts of Examples 1 to 6, respectively. In the figure, the ammonia slip is shown on the ordinate relative to each of the five steady state points for samples 1 to 6 shown on the abscissa.

[0332] FIG. 9: shows the NO.sub.2 make of samples 1 to 6 for each of the five steady state points. The samples 1 to 6 refer to the catalysts of Examples 1 to 6, respectively. In the figure, the NO.sub.2 make is shown on the ordinate relative to each of the five steady state points for samples 1 to 6 shown on the abscissa.

[0333] FIG. 10: shows the NO.sub.2/NO.sub.x ratio at an ammonia to nitrogen ratio (normalized stoichiometric ratio=NSR) of 0 for the Layered AMOx design 8 g/ft.sup.3 and for the Mixed AMOx design 8 g/ft.sup.3 for each of the seven steady state points. The Layered AMOx design 8 g/ft.sup.3 refers to Example 7 and the Mixed AMOx design 8 g/ft.sup.3 refers to Example 8. In the figure, the ratio of NO.sub.2/NO.sub.x is shown on the ordinate relative to each of the seven steady state points for the Layered AMOx design 8 g/ft.sup.3 and for the Mixed AMOx design 8 g/ft.sup.3 shown on the abscissa.

[0334] FIG. 11: shows the NO.sub.2/NO.sub.x ratio at an ammonia to nitrogen ratio (NSR) of 0.5 for the Layered AMOx design 8 g/ft.sup.3 and for the Mixed AMOx design 8 g/ft.sup.3 for each of the seven steady state points. The Layered AMOx design 8 g/ft.sup.3 refers to Example 7 and the Mixed AMOx design 8 g/ft.sup.3 refers to Example 8. In the figure, the ratio of NO.sub.2/NO.sub.x is shown on the ordinate relative to each of the seven steady state points for the Layered AMOx design 8 g/ft.sup.3 and for the Mixed AMOx design 8 g/ft.sup.3 shown on the abscissa.

CITED LITERATURE

[0335] WO 2015/189680 A1 [0336] U.S. Pat. No. 9,272,272 B2 [0337] U.S. Pat. No. 8,715,618 B2 [0338] U.S. Pat. No. 8,293,199 B2 [0339] U.S. Pat. No. 8,883,119 B2 [0340] U.S. Pat. No. 8,961,914 B2 [0341] U.S. Pat. No. 9,242,238 B2