| abstract |
A new type of catalyst support with oxygen storage capacity (OSC) and methods of making the same are disclosed. The composition ratio is x(Ce 1−w Zr w O 2 ):yM:zL:(1−x−y−z)Al 2 O 3 , where Ce 1−w Zr w O 2 is the oxygen storage composition with stabilizer Zr0 2 , molar ratio (w) in the range of 0 to about 0.8, and a weight ratio (x) of about 0.05 to about 0.8; M is an interactive promoter for oxygen storage capacity with a weight ratio (y) of 0 to about 0.10; and L is a stabilizer for the support Al 2 O 3 with weight ratio (z) of from 0 to about 0.10. In some cases, M or L can act as both OSC promoter and thermal stabilizer. The weight percentage range of ceria-zirconia and other metal and rare earth oxides (x+y+z) is from about 5 to about 80% relative to total oxides. Combining platinum group metals (PGM) and adhesive with the catalyst supports, a new wash coat made therefrom is provided that comprises a mixture of catalyst support materials according to the relationship (a)RE-Ce—ZrO 2 +(3)CZMLA+(1−a−β)RE-Al 2 O 3 , where RE-Ce—ZrO 2 is a commercial OSC material of rare earth elements stabilized ceria zirconia having a weight ratio (a) ranging from 0 to about 0.7; CZMLA is the catalyst support material of the present disclosure having a weight ratio (β) ranging from about 0.2 to about 1 such that (α+β)<1; and RE-Al 2 0 3 is rare earth element stabilized alumina having a weight ratio equal to (1−α−β). The new wash coat made therefrom exhibits a lower activation temperature compared with traditional formulation of wash coat by at least 50° C. The new wash coat made therefrom also requires less RE-Ce—ZrO 2 oxide and/or less PGM in the formulation of emission control catalyst for gasoline and diesel engines. |