Patent ID: 6897182

Claim:
A catalyst for purification of exhaust gases in oxygen-rich atmospheres in which oxygen concentrations of the exhaust gases are at the stoichiometric point or more required for oxidizing components to oxidized therein, consisting essentially of: (1) a catalysis-promoting coating comprising a noble metal catalyst and a NOx storage component loaded onto a carrier material, wherein the NOx storage component comprises an alkali metal and, (2) a ceramic substrate for supporting the catalysis-promoting coating, wherein the ceramic substrate exhibits resistance to alkali metal migration below 1000° C., and a coefficient of thermal expansion of less than about 25×10 −7 /° C. (25-800° C.). wherein the ceramic substrate comprises a silicate and phosphate free material selected from the group consisting of calcium aluminate, magnesiun dititanate, iron titanate zirconium titanate, and mixtures and solid solutions thereof; and wherein the material further includes a second phase formed with constituents selected from the group consisting of K 2 Al 2 O 4 , Li 2 Al 2 O 4 , MgAl 2 O 4 , ZnO, SrO and Y 2 O 3 .