| abstract |
1. A method of obtaining a new metal-promoted zeolite catalyst for selective catalytic reduction of NOx, said catalyst is synthesized by a method comprising the steps of:! - ion exchange of said metal into zeolite,! - post-treatment of said metal exchanged zeolite with hydrothermal treatment, and! - where said catalyst has improved NOx reduction activity in selective catalytic reduction compared to a metal-exchanged zeolite catalyst not treated with step b. ! 2. The method according to claim 1, wherein said zeolite is selected from the group consisting of zeolite Y, foyasites, ultrastable Y, ZSM-3, ZSM-20, CSZ-1, ECR-30, LZ-210, zeolite L, ferrierite, MSM-22 and offretitis, and wherein said metal is selected from the group comprising metal ions of vanadium, chromium, manganese, iron, cobalt, nickel, copper and cerium. ! 3. The method according to claim 1, wherein said metal ion exchange occurs in an aqueous exchange solution with a pH of from about 2.5 to about 3.5. ! 4. The method according to claim 1, in which the aforementioned metal-exchanged zeolite is hydrothermally treated at a temperature of from about 540 to about 1000 ° C, steam with a concentration of from about 5 to about 100%, for from about 5 minutes to about 250 hours! 5. Copper containing aluminosilicate zeolite catalyst formed by the method according to claim 1. ! 6. A hydrothermally stable zeolite catalyst for the selective reduction of nitrogen oxides, said catalyst includes: a metal-promoted zeolite catalyst, in which said metal-promoted zeolite must be processed to form an al |