Activity and characterization of bimetallic ZSM-5 for the selective catalytic reduction of NOx

Bimetallic catalyst, Pt-Cu-ZSM5 was prepared, tested and characterized for the selective catalytic reduction of NOx with i-C4H10 in excess of oxygen. The bimetallic catalyst was found to offer wider temperature window than that of monocatalysts, Pt-ZSM5 and Cu-ZSM5, respectively, for optimum reduction of NO. More than 50% of NO conversion was obtained in the temperature range of 250-520 degreesC. Even though the catalyst appeared to be unaffected by the excess oxygen and high space velocity, it was prone to deactivation in water vapor and sulfur dioxide. The formation of nitrous oxide as a major by product was also favorable at low temperatures. Characterization of the bimetallic catalyst suggested that copper and platinum species existed independently in the form of metal particles and metal oxides while successive metal loadings seemed to cause loss of some acid sites. (C) 2002 Elsevier Science B.V. All rights reserved.