Age-Resistant Catalyst for Oxidation of NO to NO2 in Exhaust Streams

Abstract

The present invention relates to a zeolite comprising platinum. The invention furthermore relates to a method for producing said zeolite comprising platinum according to the invention, to the use of said zeolite as an oxidation catalyst and hydrocarbon reservoir and to a catalyst component comprising the zeolite according to the invention.

1 . Method for producing a platinum-containing zeolite comprising the steps
 a) impregnating a zeolite with a platinum sulphite solution,   b) calcining the impregnated zeolite under a protective atmosphere.   
     
     
         2 . Method according to  claim 1 , wherein the calcining takes place in an argon, helium, neon or nitrogen atmosphere. 
     
     
         3 . Method according to  claim 1 , wherein the calcining takes place at a temperature of from 600 to 900° C. 
     
     
         4 . Method according to  claim 1 , wherein a reduction takes place following the calcining. 
     
     
         5 . Method according to  claim 4 , wherein the reduction takes place with a mixture of reducing gas and an inert gas. 
     
     
         6 . Method according to  claim 4 , wherein the reduction takes place over a period of from 3 to 7 hours. 
     
     
         7 . Method according to  claim 4 , wherein the reduction takes place at a temperature of from 200 to 500° C. 
     
     
         8 . Method according to  claim 1 , wherein a zeolite selected from the group consisting of the types AEL, BEA, CHA, EUO, FAU, FER, KFI, LTA, LTL, MAZ, MOR, MEL, MTW, LEV, OFF, TON and MFI is used as zeolite. 
     
     
         9 . Method according to  claim 1 , wherein the zeolite used has an SiO 2 /Al 2 O 3  modulus of from 5 to 300. 
     
     
         10 . Zeolite, produced using a method according to  claim 1 . 
     
     
         11 . Zeolite containing at least 2 wt.-% platinum, characterized in that at least 90% of the platinum is located in the pores of the zeolite. 
     
     
         12 . Zeolite according to  claim 10 , characterized in that at least 95% of the platinum is located in the pores of the zeolite. 
     
     
         13 . Zeolite according to  claim 10 , characterized in that the zeolite contains at least 3 wt.-% platinum. 
     
     
         14 . Zeolite according to  claim 10 , wherein the zeolite is selected from the group consisting of the types AEL, BEA, CHA, EUO, FAU, FER, KFI, LTA, LTL, MAZ, MOR, MEL, MTW, LEV, OFF, TON and MFI. 
     
     
         15 . Zeolite according to  claim 10 , wherein the zeolite has an SiO 2 /Al 2 O 3  modulus of from 10 to 300. 
     
     
         16 . Zeolite according to  claim 10 , wherein the zeolite is a metal-exchanged zeolite. 
     
     
         17 . Zeolite according to  claim 10 , characterized by a Pt—C═O stretching vibration of between 2070 and 2110 cm −1 , preferably from about 2080 to 2095 cm −1  and/or wherein the X-ray diffractogram (XRD) is free of Pt reflexes. 
     
     
         18 . Use of a zeolite according to  claim 10  as oxidation catalyst and hydrocarbon reservoir. 
     
     
         19 . Catalyst component containing a zeolite according to  claim 10 . 
     
     
         20 . Catalyst component according to  claim 19  comprising a support, wherein the zeolite is present as coating on the support. 
     
     
         21 . Zeolite according to  claim 11 , characterized in that at least 95% of the platinum is located in the pores of the zeolite. 
     
     
         22 . Zeolite according to  claim 11 , characterized in that the zeolite contains at least 3 wt.-% platinum. 
     
     
         23 . Zeolite according to  claim 11 , wherein the zeolite is selected from the group consisting of the types AEL, BEA, CHA, EUO, FAU, FER, KFI, LTA, LTL, MAZ, MOR, MEL, MTW, LEV, OFF, TON and MFI. 
     
     
         24 . Zeolite according to  claim 11 , wherein the zeolite has an SiO 2 /Al 2 O 3  modulus of from 10 to 300. 
     
     
         25 . Zeolite according to  claim 11 , wherein the zeolite is a metal-exchanged zeolite. 
     
     
         26 . Zeolite according to  claim 11 , characterized by a Pt—C═O stretching vibration of between 2070 and 2110 cm −1 , preferably from about 2080 to 2095 cm −1  and/or wherein the X-ray diffractogram (XRD) is free of Pt reflexes. 
     
     
         27 . Use of a zeolite according to  claim 11  as oxidation catalyst and hydrocarbon reservoir. 
     
     
         28 . Catalyst component containing a zeolite according to  claim 11 . 
     
     
         29 . Catalyst component according to  claim 28  comprising a support, wherein the zeolite is present as coating on the support.