Scr catalyst compositions and scr catalytic articles comprising said catalyst compositions

Abstract

The present invention disclose catalyst compositions for the selective catalytic reduction of nitrogen oxides, consisting of at least one oxide of vanadium in an amount of 2.0 to 4.0 wt.-%, calculated as VOand based on the total weight of the catalyst composition, at least one oxide of tungsten in an amount of 2.5 to 7.2 wt.-%, calculated as WOand based on the total weight of the catalyst composition, at least one oxide of antimony in an amount of 0.6 to 3.4 wt.-%, calculated as SbOand based on the total weight of the catalyst composition, at least one oxide of zirconium in an amount of 0 to 1.0 wt.-%, calculated as ZrOand based on the total weight of the catalyst, and at least one oxide of titanium in an amount of 84.6 to 94.9 wt.-% calculated as TiOand based on the total weight of the catalyst, wherein the weight ratio of the oxides of vanadium, tungsten, antimony, titanium and optionally zirconium, calculated as VO, WO, SbO, TiOand optionally ZrC, respectively, add up to 100 wt.-%. Furthermore, SCR catalytic articles are disclosed wherein an SCR catalyst composition according to the invention is affixed in the form of a coating. Suitable catalyst carriers are corrugated substrates and cordierite monoliths. The SCR catalytic articles can be used in a method for the reduction of nitrogen oxides in exhaust gases of lean-burn internal combustion engines, and they can furthermore be comprised in an exhaust gas purification system for the treatment of diesel exhaust gas.