Patent ID: 8641993

Claim:
A NO x absorber catalyst comprising either: (A) an extruded solid body comprising 10-95% by weight of at least one binder/matrix component; and 5-90% by weight of a zeolitic molecular sieve, a non-zeolitic molecular sieve or a mixture of any two or more thereof, and at least one metal comprising (a) at least one precious metal; and (b) at least one alkali metal or at least one alkaline earth metal, wherein (a) and (b) are carried in one or more coating layer(s) on a surface of the extruded solid body; or (B) an extruded solid body comprising 10-95% by weight of at least one binder/matrix component; 5-80% by weight optionally stabilised ceria; and at least one metal comprising (a) at least one precious metal; and (b) at least one alkali metal or at least one alkaline earth metal, and a zeolitic molecular sieve, non-zeolitic molecular sieve or any mixture of any two or more thereof present in a separate discrete layer from the ceria and the at least one alkali metal or at least one alkaline earth metal, wherein: (i) the at least one alkali metal or the at least one alkaline earth metal is present throughout the extruded solid body; (ii) a majority of the at least one alkali metal or the at least one alkaline earth metal is located at a surface of the extruded solid body; (iii) the at least one alkali metal or the at least one alkaline earth metal is carried in one or more coating layer(s) on a surface of the extruded solid body; (iv) the at least one alkali metal or the at least one alkaline earth metal is present throughout the extruded solid body and is also present in a higher concentration at a surface of the extruded solid body; (v) the at least one alkali metal or the at least one alkaline earth metal is present throughout the extruded solid body and is also carried in one or more coating layer(s) on a surface of the extruded solid body; or (vi) the at least one alkali metal or the at least one alkaline earth metal is present throughout the extruded solid body, is present in a higher concentration at a surface of the extruded solid body and is also carried in one or more coating layer(s) on the surface of the extruded solid body.