Non-zeolite base metal SCR catalyst

1. A catalyst for treating a gas containing nitrogen oxides comprising:

(b) a catalytic composition containing at least one catalytic component consisting of (i) at least one transition metal dispersed on a mixed oxide or composite oxide or a mixture thereof as support material consisting of cerium and zirconium; or (ii) cerium oxide and zirconium oxide as single oxides or a composite oxide thereof or a mixture of the single oxides and the composite oxide dispersed on an inert oxide support material, wherein at least one transition metal is dispersed thereon, wherein the at least one transition metal is selected from the group consisting of a Group VIB metal, a Group IB metal, a Group IVA metal, a Group VB metal, a Group VIIB metal, a Group VIII metal and mixtures of any two or more thereof, provided that at least one selected transition metal is tungsten, provided that the content of cerium and zirconium as oxides in the catalytic component is Ce x Zr 1-x O 2 , wherein X=0.1-0.5.

2. The catalyst according to claim 1 , wherein the content of cerium and zirconium as oxides in the catalytic component is Ce x Zr 1-x O 2 , wherein X=0.2-0.5.

3. The catalyst according to claim 1 , wherein the two or more transition metals are selected from the group consisting of Cr, Ce, Mn, Fe, Co, Ni, W and Cu.

4. The catalyst according to claim 3 , wherein the two or more transition metals are selected from the group consisting of Fe, W, Ce, Mn and Cu.

5. The catalyst according to claim 3 , wherein the two or more transition metals comprise iron and manganese.

6. The catalyst according to claim 3 , wherein the two or more transition metals comprise iron and tungsten.

7. The catalyst according to claim 1 , wherein the total at least one transition metal present in the catalytic component is from 0.1 to 30 wt %, based on the total weight of the catalytic component.

8. The catalyst according to claim 1 , wherein the catalytic component consists of (ii) and the inert oxide support is selected from the group consisting of alumina, titania, non-zeolite silica-alumina, ceria, zirconia and mixtures, composite oxides and mixed oxides of any two or more thereof.

9. The catalyst according to claim 1 , wherein said catalytic component has been activated at a temperature of at least 600° C.

10. The catalyst of claim 1 , wherein said catalytic composition further comprises a second catalytic component consisting of iron and tungsten dispersed on zirconia.

11. The catalyst of claim 10 , wherein said first catalytic component and said second catalytic component are disposed in separate zones or layers.

12. The catalyst of claim 11 , wherein said catalytic composition is a blend of said first and second catalytic components.

13. A catalyst for treating gas containing nitrogen oxides comprising:

a catalytic composition containing at least one catalytic component consisting of (i) two or more transition metals dispersed on a mixed oxide or composite oxide or a mixture thereof as support material consisting of cerium and zirconium; or (ii) cerium oxide and zirconium oxide as single oxides or a composite oxide thereof or a mixture of the single oxides and the composite oxide dispersed on an inert oxide support material, whereon is dispersed at least two transition metals, provided that at least one of the metals is tungsten.

14. The catalyst of claim 13 , a second transition metal is selected from the group consisting of a Group VIB metal, a Group IB metal, a Group IVA metal, a Group VB metal, a Group VIIB metal, a Group VIII metal and mixtures of any two or more thereof.

15. The catalyst of claim 13 , wherein the content of cerium and zirconium as oxides in the catalyst is Ce x Zr 1-x O 2 , wherein X=0.1-0.9.

16. The catalyst of claim 15 , wherein X=0.1-0.5.