Wide temperature window in the catalytic activity of novel Pt/ZSM-5 prepared by a sublimation method for selective catalytic reduction of NO

Abstract

The removal of nitric oxide from the exhaust gas of lean-burn engines is not fully commercialized since the current catalyst technology cannot meet the strict future emission regulations. Although ZSM-5 ion-exchanged with Pt(Pt/ZSM-5) has been considered as a promising catalyst due to its superior low-temperature activity, it has the drawback of a narrow "temperature window" for activity, i.e. an abrupt decrease in the activity above 300 8 This paper reports on the preparation of novel Pt/ZSM-5 by subliming Pt(CO)(2)Cl-2 into H-ZSM-5 at 220degreesC resulting in excellent activity within a wide temperature window between 230 and 500degreesC. Pre-treatment of this Pt/ZSM-5 can change the width of the temperature window. Moreover, H2O plays a role as a promoter and SO2 reversibly reduces the activity by less than 20%.