Platinum group metal-free catalysts for reducing the ignition temperature of particulates on a diesel particulate filter

Abstract

A catalyzed diesel particulate filter (CDPF) and a method for filtering particulates from diesel engine exhaust are provided, where the catalyzed diesel particulate filter includes a substrate and a catalyst composition, where the catalyst composition contains at least one first component, at least one second component, and at least one third component, where the first component is at least one first component selected from the group consisting of cerium and a lanthanide and mixtures thereof, the at least one second component is selected from the group consisting of cobalt, copper, manganese and mixtures thereof; and the third component comprises strontium, where the first component, the second component, and the third component are in an oxide form after calcination. The catalyst on the catalyzed diesel particulate filter lowers the temperature at which particulates are removed from the CDPF by oxidizing the particulates on the filter. The catalyzed diesel particulate filter may also include a washcoat. Washcoats prepared from colloidal aluminum oxide may have higher surface areas and pore volumes loadings than washcoats containing aluminum oxide prepared from aluminum nitrate.

1 - 19 . (canceled) 
     
     
         20 . A method of removing particulates from exhaust gas from a diesel engine, said method comprising contacting said exhaust gas with a catalyzed diesel particulate filter, thereby removing said particulates from the exhaust gas, wherein said catalyzed diesel particulate filter comprises:
 a substrate; and   a catalyst composition comprising:
 a) at least one first component selected from the group consisting of cerium and a lanthanide; and 
 b) at least one second component selected from the group consisting of cobalt, copper, manganese and mixtures thereon, 
 wherein said first component and said second component are in an oxide form, and further wherein the catalyst composition does not comprise metal sulfates and platinum group metals. 
   
     
     
         21 . The method of  claim 20 , wherein:
 a) when second component comprises cobalt, a molar ratio of the first component to the second component is in a range of 35-70:5-45; and   b) when said second component comprises manganese, a molar ratio of the first component to the second component is in a range of 15-60:30-70.   
     
     
         22 . The method of  claim 20 , wherein a loading of said catalyst composition on said catalyzed diesel particulate filter is in a range of approximately 10 g/L to approximately 60 g/L, wherein the loading is on the basis of the oxides. 
     
     
         23 . The method of  claim 20 , wherein said catalyzed diesel particulate filter further comprises a washcoat. 
     
     
         24 . The method of  claim 23 , wherein said washcoat comprises aluminum oxide. 
     
     
         25 . The method of  claim 24 , wherein said washcoat further comprises at least one oxide selected from the group consisting of silica alumina, a zeolite, silica, cerium oxide, lanthanide oxide, zirconium oxide, and mixtures thereof. 
     
     
         26 . The method of  claim 20  further comprising removing at least a portion of said particulates from said catalyzed diesel particulate filter by contacting said catalyzed diesel particulate filter with an oxidizing gas. 
     
     
         27 . The method of  claim 26 , wherein said oxidizing gas is selected from the group consisting of O 2 , NO, and NO 2 . 
     
     
         28 . The method of  claim 26 , wherein said catalyzed diesel particulate filter is contacted with said oxidizing gas at a temperature of approximately 100° C. to approximately 800° C. 
     
     
         29 . The method of  claim 20 , further comprising contacting said exhaust gas with a diesel oxidation catalyst, wherein contacting said exhaust gas with said diesel oxidation catalyst is before contacting said exhaust gas with said catalyzed diesel particulate filter. 
     
     
         30 . The method of  claim 20 , wherein the catalyst composition further comprises at least one third component comprising strontium, wherein said first component, said second component, and said third component are in an oxide form after calcination. 
     
     
         31 . The method of  claim 30 , wherein:
 a) when second component comprises cobalt, a molar ratio of the first component to the second component to the third component is in a range of 35-70:5-45: 5-35; and   b) when said second component comprises manganese, a molar ratio of the first component to the second component to the third component is in a range of 15-60:30-70:5-35.