CATALYST FOR REMOVAL OF NITROGEN OXIDE, AND METHOD FOR REMOVAL OF NITROGEN OXIDE

摘要

A nitrogen oxide removing catalyst for removing nitrogen oxides from an exhaust gas is prevented from being poisoned by a phosphorous compound included in the exhaust gas. A nitrogen oxide removing catalyst superior in durability and a method of removing nitrogen oxides are provided. A porous material having fine holes with controlled diameters and a catalyst having an active ingredient supported in the fine holes in the porous material are used. A first invention is characterized in that the diameter of the plurality of fine holes is within a range of 8 to 9 Å. The fine hole diameter is preferably from 8 to 9 Å when the diameter is measured in a gas adsorption method in which fine holes with diameters of 3.4 to 14 Å can be measured. The fine hole diameter is also preferably from 8 to 9 Å when the fine hole diameter is calculated from a crystal structure. A second invention is characterized in that the porous material is mesoporous silica. The primary particle diameter of the mesoporous silica is preferably within a range of 150 to 300 nm.