A COMPOSITION COMPRISING A ZEOLITIC MATERIAL SUPPORTED ON A SUPPORT MATERIAL

Abstract

A composition comprising a support material which comprises silicon carbide on the surface of which a zeolitic material of the AEI/CHA family is supported, wherein at least 99 weight-% of the framework structure of the zeolitic material consist of a tetravalent element Y which is one or more of Si, Ge, Ti, Sn and V; a trivalent element X which is one or more of Al, Ga, In, and B; O; and H.

Claims

1. A composition, comprising a support material comprising silicon carbide, wherein, on a surface of the support material, a zeolitic material of the AEI/CHA family is supported, wherein at least 99 weight-% of a framework structure of the zeolitic material consists of: a tetravalent element Y which is one or more of Si, Ge, Ti, Sn and V; a trivalent element X which is one or more of Al, Ga, In, and B; O; and H.

2. The composition of claim 1, wherein the silicon carbide comprised in the support material comprises one or more of alpha silicon carbide, beta silicon carbide, and gamma silicon carbide.

3. The composition of claim 1, wherein at least 50 weight % of the support material consists of silicon carbide, wherein the support material optionally further comprises one or more of elemental silicon and silica.

4. The composition of claim 1, wherein the zeolitic material of the AEI/CHA family is a zeolitic material having framework type AEI or having framework type CHA.

5. The composition of claim 1, wherein the zeolitic material of the AEI/CHA family is a zeolitic material having framework type CHA.

6. The composition of claim 1, having one or more of the following characteristics: a BET specific surface area in a range of from 100 to 300 m.sup.2/g; a specific micropore surface area in a range of from 100 to 250 m.sup.2/g; an external surface area in a range of from 2 to 10 m.sup.2/g; a total pore volume in a range of from 0.05 to 0.20 cm.sup.3/g; a micropore volume in a range of from 0.04 to 0.15 cm.sup.3/g; an adsorption cumulative pore volume in a range of from 0.002 to 0.02 cm.sup.3/g.

7. The composition of claim 1, wherein a loading of the support material with the zeolitic material is in a range of from 5 to 50%.

8. The composition of claim 1, wherein crystallites of the zeolitic material supported on the surface of the support material are in the form of cubes wherein at least 90% of the cubes have an edge length in a range of from 1 to 10 micrometers.

9. The composition of claim 1, further comprising a transition metal.

10. The composition of claim 9, wherein a weight ratio of the transition metal, calculated as element, relative to the zeolitic material is in a range of from 0.1:1 to 5.0:1.

11. A process for preparing the composition of claim 1, the process comprising: (i) preparing an aqueous synthesis mixture comprising a source of Y, a source of X, a source of a base, and a support material comprising silicon carbide; and (ii) subjecting the synthesis mixture prepared in (i) to hydrothermal crystallization conditions, comprising heating the synthesis mixture prepared in (i) under autogenous pressure to a crystallization temperature of the zeolitic material of the AEI/CHA family, to obtain a heated synthesis mixture, and keeping the heated synthesis mixture at the crystallization temperature for a crystallization time, to obtain a crystallization mixture comprising the zeolitic material of the AEI/CHA family supported on the surface of the support material and a mother liquor.

12. The process of claim 11, wherein Y is Si and the source of Y comprises one or more of a silicate, a silica, a silicic acid, a colloidal silica, a fumed silica, a tetraalkoxysilane, a silica hydroxide, a precipitated silica and a clay; wherein X is Al and the source of X is one or more of a metallic aluminum, an aluminate, an aluminum alcoholate and an aluminum hydroxide; and wherein the source of the base is a source of one or more of an alkali metal and an alkaline earth metal.

13. The process of claim 11, wherein in the synthesis mixture prepared in (i) and subjected to (ii), a weight ratio of the base relative to the sum of a weight of the source of Y, calculated as YO.sub.2, and a weight of the source of X, calculated as X(OH).sub.3, is greater than 1.5:1.

14. The process of claim 11, wherein the zeolitic material has framework type CHA, and wherein the synthesis mixture prepared in (i) and subjected to (ii) further comprises a CHA framework structure directing agent comprising one or more of a N-alkyl-3-quinuclidinol, a N,N,N-trialkyl-exoaminonorbornane, a N,N,N-trimethyl-1-adamantylammonium compound, a N,N,N-trimethyl-2-adamantylammonium compound, a N,N,N-trimethylcyclohexylammonium compound, a N,N-dimethyl-3,3-dimethylpiperidinium compound, a N,N-methylethyl-3,3-dimethylpiperidinium compound, a N,N-dimethyl-2-methylpiperidinium compound, 1,3,3,6,6-pentamethyl-6-azonio-bicyclo(3.2.1)octane, N,N-dimethylcyclohexylamine, and a N,N,N-trimethylbenzylammonium compound.

15. The process of claim 11, wherein the crystallization temperature according to (ii) is in a range of from 130 to 200 C.

16. The process of claim 11, further comprising subjecting the zeolitic material of the AEI/CHA family supported on the surface of the support material to ion-exchange with a transition metal.

17. A composition, comprising a support material comprising silicon carbide, wherein, on a surface of the support material, a zeolitic material of the AEI/CHA family is supported, wherein at least 99 weight-% of a framework structure of the zeolitic material consists of: a tetravalent element Y which is one or more of Si, Ge, Ti, Sn and V; a trivalent element X which is one or more of Al, Ga, In, and B; O; and H, and wherein the composition is obtainable or obtained by the process of claim 11.

18. An article, wherein the article is a catalyst or a catalyst component comprising the composition of claim 1.

19. A method of treating an exhaust gas stream, the method comprising contacting the exhaust gas stream with the article of claim 18.

Description

SHORT DESCRIPTION OF THE FIGURES

[0189] FIG. 1 shows XRD patterns of the SiC support material, the pure CHA zeolitic material and a typical CHA zeolitic material supported on the SiC support material as described in detail in Example 1.

[0190] FIG. 2 shows SEM images of the SiC support material in unsupported and supported state, as described in detail in Example 1.

[0191] FIG. 3 shows crystal phases and morphologies of compositions comprising a zeolitic material having CHA framework type supported on a SiC support material prepared in the presence of different amounts of NaOH aqueous solution, as described in detail in Example 1.

[0192] FIG. 4 shows crystal phases and morphologies of compositions comprising a zeolitic material having CHA framework type supported on a SiC support material prepared with different crystallization time, as described in detail in Example 1.

[0193] FIG. 5 shows N.sub.2 adsorption/desorption isotherms of a zeolitic, material having framework type CHA, a SiC support material, and a and compositions comprising a zeolitic material having CHA framework type supported on a SiC support material, as well as the BET specific surfacer area of a compositions comprising a zeolitic material having CHA framework type supported on a SiC support material as a function of synthesis time, as described in detail in Example 1

[0194] FIG. 6 shows NH.sub.3-SCR performance of a copper containing compositions comprising a zeolitic material having CHA framework type supported on a SiC support material with different copper contents in comparison to an unsupported copper containing zeolitic material having CHA framework.

CITED PRIOR ART

[0195] A. Shishkin, H. Kannisto, P. A. Carlsson, H. Harelind, M. Skoglundh; Catal. Sci. Technol. no. 4 (2014); pp. 3917-3926