Patent attributes
An exhaust gas treatment apparatus includes a device (A) which is provided in an exhaust system and which selectively reduces NOx in an exhaust gas and a device (B) which is disposed upstream of the device (A) and which decomposes urea and supplies ammonia as a NOx reducing gas, the device (B) including a urea decomposition catalyst. The catalyst is [1] a zeolite catalyst which is composed of granular molded bodies including zeolite particles or which includes a catalyst layer composed of zeolite particles disposed on a support, or [2] a honeycomb catalyst or a membranous catalyst in which metal oxide particulates adhere to a conductive honeycomb substrate or netlike support, and the metal oxide particulates are composed of at least one oxide of a metal selected from the group consisting of Na, Mg, Ca, Ba, La, Ce, Ti, Zr, V, Cr, Mo, W, Mn, Zn, Al, Si, P, Sb, Cu, Fe, Ru, Co, and Re.
