To provide a catalyst and a method for reducing and removing nitrogen oxide in exhaust gas which reduces and removes nitrogen oxide in exhaust gas in the presence of hydrocarbons which is added in a small amt. to the exhaust gas or exists in the exhaust gas under an atmosphere of oxidation condition where excess oxygen exists.
A catalyst wherein 0.1-50% by mass barium sulfate to the total mass of the catalyst are physically mixed to alumina is provided. The alumina may have 0.01-15 mass % at least one selected from transition elements and typical elements of the group IIIb, the group IVb and the group Vb in the periodic table, pref. at least one selected from Sn, Co, Ag, In, Ga and Sb. A method using the catalyst in an atmosphere where oxygen exists in the presence of hydrocarbons or a oxygen-contg. org. compd. is provided.
MIYAMOTO KATSUMI
YOSHINARI TOMOHIRO
COSMO OIL CO LTD