Patent ID: 9011809
Filing Date: 2015-04-21
Classification: B01D,B01J,Y02C,Y10S

Abstract:
1. An ammonia oxidation catalyst (AMOX) for oxidizing and removing surplus ammonia, in selectively reducing nitrogen oxides by adding urea or ammonia as a reducing agent of the nitrogen oxides and using a selective catalytic reduction (SCR) catalyst, into exhaust gas discharged from a lean-burn engine, comprising at least two catalyst layers having a catalyst layer (lower layer) comprising a noble metal element supported on an inorganic base material comprising any of a composite oxide (A) having at least titania and silica as main components, alumina, and a composite oxide (B) consisting of alumina and silica, and a catalyst layer (upper layer) comprising a composite oxide (C) consisting of at least silica, tungsten oxide, ceria, and zirconia, coated at the surface of a honeycomb structure-type substrate, wherein the composite oxide (C) comprises silica: 20% by weight or less, tungsten oxide: 1 to 50% by weight, ceria: 1 to 60% by weight, and zirconia: 30 to 90% by weight.