DENITRIFICATION CATALYST AND DENITRIFICATION METHOD USING THAT

摘要

PROBLEM TO BE SOLVED: To provide such a denitrification catalyst for an inner combustion engine that NOx in exhaust gas from an inner combustion engine with a lean air-fuel ratio can be efficiently removed at enough high space velocity and that the catalyst has high durability against stoichiometric gas, and to provide a denitrification method with high efficiency and high reliability for NOx from exhaust gas of an inner combustion engine with a lean air-fuel ratio. SOLUTION: This catalyst contains alumina, silver, zinc and phosphorus. The alumina satisfies the following relation between the pore diameter and the pore volume measured by nitrogen gas adsorption method. The sum volume (A) of pores having <=300Å pore diameter, the sum volume (B) of pares having diameter between >=25Å and <100Å, and the sum volume (C) of pores having diameter between >=100 and <=300Å are in the relation that B is >=70% of A and C is <=20% of A.