초록 ▼

A NOx removal catalyst comprising a carrier that includes a zeolite, and preferably a β-zeolite, that has undergone ion exchange with iron, and ferric oxide supported on the carrier. This NOx removal catalyst can be used favorably in a selective catalytic reduction process wherein nitrogen oxid

A NOx removal catalyst comprising a carrier that includes a zeolite, and preferably a β-zeolite, that has undergone ion exchange with iron, and ferric oxide supported on the carrier. This NOx removal catalyst can be used favorably in a selective catalytic reduction process wherein nitrogen oxides contained in the exhaust gas from a diesel engine are reduced and removed by ammonia.

대표청구항 ▼

The invention claimed is: 1. A method for purifying exhaust gas from a diesel engine by selective catalytic reduction, comprising supplying urea into said exhaust gas from a diesel engine, and then bringing said exhaust gas at from 180 to 220�� C. into contact with a NOx removal catalyst, said NOx

The invention claimed is: 1. A method for purifying exhaust gas from a diesel engine by selective catalytic reduction, comprising supplying urea into said exhaust gas from a diesel engine, and then bringing said exhaust gas at from 180 to 220�� C. into contact with a NOx removal catalyst, said NOx removal catalyst compromising a carrier and ferric oxide supported on said carrier, said carrier comprising a β-zetolite that has undergone ion exchange with iron, wherein an iron ion exchange ratio, represented by a formula (1): description="In-line Formulae" end="lead"[number of mols of iron ions (Fe3+) incorporated within a unit weight of said zeolite by said ion exchange/{(number of mols of Al2O3 incorporated within a unit weight of said zeolite)��(2/3)}]��100 (1)description="In-line Formulae" end="tail" is within a range from 12 to 92%. 2. The method according to claim 1, wherein a supported quantity of said ferric oxide within said catalyst is within a range from 0.1 to 15% by weight. 3. The method according to claim 1, wherein a molar ratio of SiO2/Al2O3 within said zeolite is within a range form 15 to 300. 4. The method according to claim 1, wherein said catalyst further comprises a support substrate, wherein said ferric oxide supported on said carrier is supported on said support substrate. 5. The method according to claim 4, wherein a supported quantity of a combination of said carrier and said ferric oxide is within a range from 25 to 270 g/L per unit volume of said support substrate.