Abstract: Disclosed herein are NOx reduction catalysts, particulate filters, exhaust treatment systems, and methods of treating a gas stream. In one embodiment, a NOx reduction catalyst comprises Cea—Zrb—Rc-Ad-Me-Ox. “R” is W and/or Mn. If “R” is W, “A” is selected from the group consisting of Mo, Ta, Nb, and combinations comprising at least one of the foregoing “A”, and if “R” is Mn, A is selected from the group consisting of W, Mo, Ta, Nb, and combinations comprising at least one of the foregoing “A”. “M” is a trivalent rare earth ion. a+b+c+d+e=1. “a” is about 0.1 to about 0.6; “b” is about 0.25 to about 0.7; “c” is about 0.02 to about 0.5; and if “R” is Mn, “d” is about 0.04 to about 0.2, and if “R” is W, “d” is less than or equal to about 0.2; while “e” is less than or equal to about 0.15. The NOx reduction catalyst is capable of reducing NOx.

Abstract: The present invention relates to a process for the purification of off-gases containing nitrogen oxides. An off-gas is passed through a reactor in admixture with ammonia or an ammonia precursor over a plurality of spaced catalyst beds under conditions to reduce the nitrogen oxides to nitrogen gas while heat is liberated. After the gas stream has obtained a desired temperature, the gas flow is reversed.