EXHAUST GAS PURIFYING CATALYST AND EXHAUST GAS PURIFYING METHOD

摘要

An exhaust gas purifying catalyst comprises a substrate which carries thereon iridium as a catalyst activating substance, sulfur for improving a catalyst activity of iridium, and platinum as needed. Preferably, sulfur is contained in the form of sulfate radical. An exhaust gas purifying method comprises passing exhaust gases from an internal combustion engine through the exhaust gas purifying catalyst with an exhaust gas temperature at an inlet of the exhaust gas purifying catalyst being set to 200 to 700 DEG C. In purification of exhaust gases, the above constitution and method exhibit activity over a wide temperature range, in particular, with respect to removal of nitrogen oxides in an oxidizing atmosphere, and have heat resistance and durability to be excellent in serviceability.