SCR CATALYST

摘要

The invention relates to a catalyst comprising at least two catalytically active layers, A and B, wherein A contains a carrier oxide and components A1 and A2, and B contains a carrier oxide and components B1, B2, and B3, wherein A1, A2, and B1 to B3 are defined as disclosed in claim 1. The proportion of component A1 in layer A is thereby greater than the proportion of component B1 in layer B, wherein the proportion of layer A with respect to the total weight of layers A and B, is greater than the proportion of layer B. The invention further relates to a method for reducing nitrogen oxides in exhaust gases of lean-burn internal combustion engines and to an exhaust gas cleaning system.

主权项

1. A catalyst for the selective reduction of nitrogen oxides comprising two catalytically active layers A and B, wherein
A contains a carrier oxide and the components A1 and A2, and B contains a carrier oxide and the components B1, B2, and B3, wherein A1 and B1 stand for at least one oxide of vanadium, A2 and B2 for at least one oxide of tungsten, and B3 for at least one oxide of silicon, characterized in that
the proportion of component A1 in layer A in wt % with respect to the total weight of layer A is greater than the proportion of component B1 in layer B in wt % with respect to the total weight of layer B, andthe proportion of layer A in wt % with respect to the total weight of layers A and B is greater than the proportion of layer B.