Modified zeolites for trapping hydrocarbons

摘要

A molecular sieve structure is disclosed for adsorbing hydrocarbons emitted during engine start-up, before the catalytic converter has attained its effective operating temperature. The molecular sieve can be zeolites or ceramic substrates having a zeolite surface. The molecular sieve is modified by inserting certain metal ions into the molecular sieve structure. The molecular sieve structure is also capable of releasing or desorbing the hydrocarbons when the molecular sieve reaches a certain temperature.