Pt was applied on the ceramic monolith support by double impregnation method. At first, AlAwas deposited from a Na aluminate soln., then Pt from aq. [H(3)OJ(2)][PtCl6](H2O) x soln. and the resulting catalyst system was calcinated at 500 degrees C for 3 h. The catalyst activity was tested in ethylene oxidn. at 500 degrees C by using the catalyst with or without a pretreatment with H-2. The pre-treated catalyst showed slightly higher activity but only in the range of high conversions.