US Patent 11185854 Cold start catalyst and its use in exhaust systems

A cold start catalyst is disclosed. The cold start catalyst is effective to adsorb NOx and hydrocarbons (HC) at or below a low temperature and to covert and release the adsorbed NOx and HC at temperatures above the low temperature. The cold start catalyst comprises a molecular sieve catalyst and a supported platinum group metal catalyst. The molecular sieve catalyst consists essentially of a noble metal and a molecular sieve. The supported platinum group metal catalyst comprises one or more platinum group metals and one or more inorganic oxide carriers. The invention also includes an exhaust system comprising the cold start catalyst, and a method for treating exhaust gas from an internal combustion engine utilizing the cold start catalyst.