Korea Research Institute of Chemical Technology

Seong-Hee Han

Jong-San Chang

Sang-Eon Park

Yun-Jo Lee

Gyung-Mi Kim

The present invention provides a catalyst for reduction of nitrogen oxides represented by the formula (A.sub.a O.sub.x.B.sub.b O.sub.y).(C.sub.c O.sub.z.C'.sub.c' O.sub.z')/S which is produced by supporting mixed metal oxides represented by the formula (A.sub.z O.sub.x.B.sub.b O.sub.y).(C.sub.c O.sub.z.C'.sub.c' O.sub.z') in amorphous state on aluminum or silicon-containing support at calcination temperature of 400.degree. to 700.degree. C. in a molar ratio of 0.01:1 to 5:1, and a method for removing nitrogen oxides through selective catalytic reduction which comprises converting 50 to 50,000 ppm of nitrogen oxides in exhaust gas from automobile or from fixed source such as plant turbine and boiler, and other industry in a state of having 0.1 to 20% of excessive oxygen over (A.sub.a O.sub.x.B.sub.b O.sub.y).(C.sub.c O.sub.z.C'.sub.c' O.sub.z')/S catalyst by using 100 to 100,000 ppm of hydrocarbon reducing agent having 1 to 5 carbons under the reaction condition of 200.degree. to 800.degree. C. of reaction temperature, 1 to 10 atmosphere of reaction pressure and 1000 to 100,000/hour of space velocity into nitrogen in which A and B are lanthanide metals, such as lanthanum, cerium, praseodymium or neodymium, and alkali metals or alkaline earth metals, such as sodium, potassium, rubidium, cesium, magnesium, calcium, strontium or barium, C and C' are transition metals of the first period, such as cobalt, copper, nickel, manganese, iron, vanadium, titanium, chromium and zinc, and noble metals, such as platinum, rhodium, iridium, ruthenium, rhenium, palladium and silver, a, b, c and c' have stoichiometrically 0 to 1, provided with a+b=1, c+c'=1 and is in the range of 0.1-3.0:1.0, and S is aluminum or silicon-containing support, and is zeolite, silica, alumina or silica-alumina.

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Seoul, South Korea

Seong-Hee Han