Nox removal catalyst and method of purifying exhaust gas by using the same

摘要

A NOx removal catalyst resistant to high temperatures, comprising an activated alumina wherein the specific surface area measured by the nitrogen adsorption method is 120 m2/g or more, the bulk density measured by the mercury porosimetry is 0.60 g/cm3 or more, and the skeleton density measured by the mercury porosimetry is 1.80 g/cm3 or less and silver carried on said activated alumina. When said catalyst or a structure having said catalyst coated on a substrate is brought in contact with exhaust gas from an internal combustion engine that is operated at a lean fuel/air ratio, such as a lean-burn engine, NOx can be removed efficiently within a quite short contact time.