| abstract |
Described is a selective catalytic reduction catalyst comprising a zeolite framework material of silicon and aluminum atoms, wherein the fraction of silicon atoms is isomorphically substituted with a tetravalent metal. The catalyst may comprise an accelerator metal that allows the catalyst to effectively promote the reaction of ammonia and nitrogen oxides forming nitrogen and H 2 O, selectively over a temperature range of 150 to 650 ° C. In another aspect, a selective catalytic reduction complex comprising an SCR catalyst material, and an ammonia storage material comprising a transition metal having an oxidation state of IV, is described. The SCR catalytic material selectively catalyzes the reaction of ammonia with nitrogen oxides forming nitrogen and H 2 O over a temperature range of 150 ° C. to 600 ° C. and the SCR catalytic material is effective to store ammonia at temperatures above 400 ° C. . A method of selectively reducing nitrogen oxides and a method of selectively reducing nitrogen oxides while simultaneously storing ammonia are also described. Additionally, an exhaust gas treatment system is also described. |