Catalyst with lanthamide-doped zirconia and methods of making

Abstract

The invention generally relates to three-way catalysts and catalyst formulations capable of simultaneously converting nitrogen oxides, carbon monoxide, and hydrocarbons into less toxic compounds. Such three-way catalyst formulations contain ZrO 2 -based mixed-metal oxide support oxides doped with an amount of lanthanide. Three-way catalyst formulations with the support oxides of the present invention demonstrate higher catalytic activity, efficiency and longevity than comparable catalysts formulated with traditional support oxides.

1 . A support oxide comprising ZrO 2  doped with an amount of lanthanide. 
     
     
         2 . The support oxide of  claim 1 , wherein said support oxide further comprises Al 2 O 3  or La—Al 2 O 3 . 
     
     
         3 . The support oxide of  claim 1 , wherein said lanthanide is La or Pr. 
     
     
         4 . The support oxide of  claim 1 , wherein the ZrO 2  is doped with between about 1-30% of said lanthanide. 
     
     
         5 . The support oxide of  claim 4 , wherein the ZrO 2  is doped with between about 5-15% of said lanthanide. 
     
     
         6 . The support oxide of  claim 1 , wherein said support oxide comprises La X % Zr (1-X) % O 2  and/or Pr X % Zr (1-X) % O 2 . 
     
     
         7 . The support oxide of  claim 6 , wherein said support oxide comprises La 5% Zr 95% O 2 , Pr 5% Zr 95% O 2 , La 10% Zr 90% O 2 , Pr 10% Zr 90% O 2 , La 15% Zr 85% O 2 , Pr 15% Zr 85% O 2 , or mixtures thereof. 
     
     
         8 . The support oxide of  claim 1 , wherein said support oxide is in the tetragonal phase. 
     
     
         9 . The support oxide of  claim 1 , wherein said support oxide further comprises an oxygen storage material (OSM). 
     
     
         10 . A washcoat or overcoat comprising a support oxide, an oxygen storage material (OSM) and a catalyst, wherein said support oxide is according to  claim 1 . 
     
     
         11 . The washcoat or overcoat of  claim 10 , wherein said catalyst is a platinum group metal (PGM) catalyst. 
     
     
         12 . The washcoat or overcoat of  claim 11 , wherein said PGM is Rh, Pt, Pd, or a mixture thereof. 
     
     
         13 . The washcoat or overcoat of  claim 12 , wherein said PGM is Rh. 
     
     
         14 . The washcoat or overcoat of  claim 13 , wherein said Rh is present at 0.25% (by weight) of said washcoat. 
     
     
         15 . The washcoat or overcoat of  claim 10 , wherein said support oxide constitutes 1-100% (by weight) of said washcoat or overcoat. 
     
     
         16 . A washcoat or overcoat comprising:
 a) (i) 40% oxygen storage material (OSM); (ii) 30% Al 2 O 3  or La—Al 2 O 3 ; and (iii) 30% Pr 0.05 Zr 0.95 O 2 ;   b) (i) 40% OSM; (ii) 30% Al 2 O 3  or La—Al 2 O 3 ; and (iii) 30% La 0.05 Zr 0.95 O 2 ;   c) (i) 40% OSM; 30% Al 2 O 3  or La—Al 2 O 3 ; and (iii) 30% Pr 0.10 Zr 0.90 O 2 ;   d) (i) 40% OSM; 30% Al 2 O 3  or La—Al 2 O 3 ; and (iii) 30% La 0.10 Zr 0.90 O 2 ;   e) (i) 40% OSM; 30% Al 2 O 3  or La—Al 2 O 3 ; and (iii) 30% Pr 0.15 Zr 0.85 O 2 ;   f) (i) 40% OSM; 30% Al 2 O 3  or La—Al 2 O 3 ; and (iii) 30% La 0.15 Zr 0.85 O 2 ;   g) (i) 40% OSM; and (ii) 60% Pr 0.05 Zr 0.95 O 2 ;   h) (i) 40% OSM; and (ii) 60% La 0.05 Zr 0.95 O 2 ;   i) (i) 40% OSM; and (ii) 60% Pr 0.10 Zr 0.90 O 2 ;   j) (i) 40% OSM; and (ii) 60% La 0.10 Zr 0.90 O 2 ;   k) (i) 40% OSM; and (ii) 60% Pr 0.15 Zr 0.85 O 2 ; or   l) (i) 40% OSM; and (ii) 60% La 0.15 Zr 0.85 O 2 .   
     
     
         17 . A washcoat or overcoat according to  claim 15 , wherein said OSM is:
   Ce 1-a-b-c-d D a E b F c Zr d O 2 ,   
       wherein:
 a, b and c are, independently, 0-0.7; 
 d is 0-0.9; and 
 D, E and F are, independently, selected from the group consisting of lanthanides, alkaline earth metals and transition metals. 
 
     
     
         18 . A washcoat or overcoat according to  claim 17 , wherein said OSM is Ce 0.3 Nd 0.05 Pr 0.05 Zr 0.6 O 2 . 
     
     
         19 . A catalyst system comprising: a substrate and a washcoat,
 wherein said washcoat is according to  claim 10 .   
     
     
         20 . A catalyst system comprising: a substrate, a washcoat, and an overcoat,
 wherein said washcoat is according to  claim 10 ; and   said overcoat comprises a support oxide, an oxygen storage material (OSM), and a catalyst.   
     
     
         21 . A catalyst system comprising: a substrate, a washcoat, and an overcoat,
 wherein said washcoat comprises a support oxide, an oxygen storage material (OSM) and a catalyst; and   wherein said overcoat is according to  claim 10 .   
     
     
         22 . The catalyst system of  claim 21 , wherein said catalyst in said overcoat is a platinum group metal (PGM) catalyst. 
     
     
         23 . The catalyst system of  claim 22 , wherein said catalyst in said overcoat is Rh, Pt, Pd, or a mixture thereof. 
     
     
         24 . The catalyst system of  claim 23 , wherein said catalyst in said overcoat is Pd. 
     
     
         25 . The catalyst system of  claim 24 , wherein said Pd is present at 100 g/ft 3 . 
     
     
         26 . The catalyst system of  claim 21 , wherein said catalyst in said washcoat is a platinum group metal (PGM) catalyst. 
     
     
         27 . The catalyst system of  claim 26 , wherein said catalyst in said washcoat is Rh, Pt, Pd, or a mixture thereof. 
     
     
         28 . The catalyst system of  claim 27 , wherein said catalyst in said washcoat is Pd. 
     
     
         29 . The catalyst of  claim 28 , wherein said Pd is present at 100 g/ft 3 . 
     
     
         30 . The catalyst system of  claim 19 , wherein said catalyst system is a three way conversion catalyst system. 
     
     
         31 . The catalyst system of  claim 19 , wherein said catalyst system exhibits improved gas flow when compared to catalyst systems comprising only traditional support oxides. 
     
     
         32 . The catalyst system of  claim 19 , wherein said catalyst system exhibits improved light-off performance when compared to catalyst systems comprising only traditional support oxides. 
     
     
         33 . A method of making a catalyst system comprising:
 a) depositing a washcoat according to  claim 10  on a substrate;   b) treating said washcoat and substrate by calcination; and   c) optionally impregnating a platinum group metal (PGM) catalyst into said washcoat, followed by drying and calcination.   
     
     
         34 . A method of making a catalyst system comprising:
 a) depositing a washcoat according to  claim 10  on a substrate;   b) treating said washcoat and substrate by calcination;   c) optionally impregnating a platinum group metal (PGM) catalyst into said washcoat, followed by drying and calcination;   d) depositing an overcoat onto the washcoat;
 wherein said overcoat comprises a support oxide, an oxygen storage material and a catalyst; 
   e) optionally impregnating a PGM catalyst into said overcoat, followed by drying and calcination.   
     
     
         35 . A method of making a catalyst system comprising:
 a) depositing a washcoat on a substrate,
 wherein said washcoat comprises a support oxide, an oxygen storage material and a catalyst; 
   b) treating said washcoat and substrate by calcination;   c) optionally impregnating a platinum group metal (PGM) catalyst into said washcoat, followed by drying and calcination;   d) depositing an overcoat according to  claim 10  onto the washcoat;   e) optionally impregnating a PGM catalyst into said overcoat, followed by drying and calcination.   
     
     
         36 . (canceled) 
     
     
         37 . (canceled) 
     
     
         38 . (canceled) 
     
     
         39 . (canceled) 
     
     
         40 . (canceled)