CATALYST BED FOR CLEANING OF EXHAUST, GAS CATALYTIC STRUCTURE FOR CLEANING OF EXHAUST GAS AND METHOD FOR CLEANING EXHAUST GAS WITH THE SAME

摘要

PROBLEM TO BE SOLVED: To provide a catalyst capable of efficiently removing NOx in exhaust gas from an internal combustion engine operated in a lean burning region and a method for cleaning exhaust gas with the catalyst so that NOx in exhaust gas from an internal combustion engine can be removed with high efficiency and high reliability. SOLUTION: This catalyst bed for cleaning of exhaust gas consists of a catalyst obtd. by incorporating Ag, Zn and P into a porous alumina carrier and a catalyst obtd. by incorporating Au, Zn and P into a porous alumina carrier. Each of the alumina carriers has the following relation between pore radius and pore volume measured by a gaseous nitrogen adsorption method; the total pore volume Y of pores each having 25 to <100Å pore radius is >=70% of the total pore volume X of pores each having <=300Å pore radius and the total pore volume Z of pores each having 100-300Å pore radius is <=20% of the total pore volume X.