Synergized PGM Catalyst Systems for Diesel Oxidation Catalyst Applications

Abstract

Synergized platinum group metals (SPGM) oxidation catalyst systems are disclosed. Disclosed SPGM oxidation catalyst systems may include a washcoat with a Cu—Mn spinel structure and an overcoat including PGM, such as palladium (Pd), platinum (Pt), rhodium (Rh), or combinations thereof, supported on carrier material oxides. SPGM systems show significant improvement in abatement of unburned hydrocarbons (HC) and carbon monoxide (CO), and the oxidation of NO to NO 2 , which allows reduction of fuel consumption. Disclosed SPGM oxidation catalyst systems exhibit enhanced catalytic activity compared to PGM oxidation systems, showing that there is a synergistic effect between PGM and Cu—Mn spinel composition within the disclosed SPGM oxidation catalyst systems. Disclosed SPGM oxidation catalyst systems may be available for a plurality of DOC applications.

What is claimed is: 
     
         1 . A synergized platinum group metal (SPGM) catalyst system, comprising:
 at least one substrate comprising at least one metal;   at least one washcoat comprising at least one oxygen storage material further comprising Cu—Mn having a niobium-zirconia support oxide; and   at least one overcoat comprising at least one platinum group metal catalyst;   wherein the at least one platinum group metal catalyst comprises at least one selected from the group consisting of palladium, a bimetallic composite of platinum and rhodium, and combinations thereof;   wherein the at least one overcoat is supported on at least one carrier material oxide comprising alumina.   
     
     
         2 . The catalyst system of  claim 1 , wherein the Cu—Mn spinel comprises CuMn 2 O 4 . 
     
     
         3 . The catalyst system of  claim 1 , wherein the at least one platinum group metal catalyst is present at about 0.5 g/ft 3  to about 25.0 g/ft 3 . 
     
     
         4 . The catalyst system of  claim 1 , wherein the at least one platinum group metal catalyst is present at about 1.0 g/ft 3 . 
     
     
         5 . The catalyst system of  claim 1 , wherein the T 50  for CO is between about 235° C. to about 325° C. 
     
     
         6 . The catalyst system of  claim 1 , wherein the T 50  for HC is between about 235° C. to about 325° C. 
     
     
         7 . The catalyst system of  claim 1 , wherein the conversion of NO is about 34% at 390° C. 
     
     
         8 . The catalyst system of  claim 1 , wherein the conversion of NO is about 18% at 465° C. 
     
     
         9 . The catalyst system of  claim 1 , wherein the conversion of NO x  is about 19% at 460° C. 
     
     
         10 . The catalyst system of  claim 1 , wherein the Cu—Mn is in spinel form. 
     
     
         11 . The catalyst system of  claim 1 , wherein the niobium-zirconia support oxide comprises Nb 2 O 5 —ZrO 2 . 
     
     
         12 . The catalyst system of  claim 1 , further comprising at least one impregnation layer. 
     
     
         13 . The catalyst of  claim 1 , wherein the at least one substrate comprises a ceramic. 
     
     
         14 . The catalyst of  claim 1 , wherein the at least one platinum group metal catalyst is prepared by co-milling. 
     
     
         15 . The catalyst of  claim 1 , wherein the at least one platinum group metal catalyst is prepared by co-precipitation.