CATALYST LAYER FOR PURIFICATION OF EXHAUST GAS, CATALYST STRUCTURAL BODY FOR PURIFICATION OF EXHAUST GAS AND PURIFYING METHOD OF EXHAUST GAS USING THESE

摘要

PROBLEM TO BE SOLVED: To obtain a catalyst layer for purification of an exhaust gas to efficiently remove NOx in a diluted combustion exhaust gas, to obtain a producing method of a catalyst-coated structural body and a purifying method of the exhaust gas. SOLUTION: This catalyst layer for purification of an exhaust gas consists of a catalyst (A) which is prepared by incorporating at least one of silver or tin on a silica carrier and a catalyst (B) which is prepared by incorporating silver on an alumina carrier. The alumina carrier has a fine porous structure showing the relation of the pore radius and the pore volume described as follows. The sum X of the volume of pores having <=300 Å pore radius, the sum Y of the volume of pores having >=25 Åand <100 Å pore radius, and the sum Z of the volume of pores having >=100 Åand <=300 Å pore radius satisfy that Y is >=70% of X and Z is <=20% of X. The catalyst layer as described above is divided and is applied to cover the inner surfaces of through holes of a supporting base material consisting of a refractory material having lots of through holes to obtain a catalyst-coated structural body for purification of the exhaust gas. The exhaust gas is purified by using the obtd. structural body.