Process for activating or reactivating ethylene oxide silver substrate catalysts

In a process for activating or reactivating silver substrate catalysts having promoter metals therein used in the production of ethylene oxide by oxidizing a mixture of gases containing ethylene and an oxygen containing gas where the mixture of gases is passed over said silver substrate catalysts in a catalyst zone and defines a flow path, the improvement comprising:

• locating a promoter bed containing uniformly distributed compounds of the promoter metals in at least a portion of said flow path of said mixture of gases and in front of said catalyst zone.