CATALYST FOR PURIFYING EXHAUST GAS

摘要

PURPOSE: To maintain the performance of a three way catalyst near a stoichiometric region as in the care of conventional one without using expensive Pt and Rh and to improve NOx purification performance in a lean region near the stoichiometric region. CONSTITUTION: A catalyst is composed of a porous carrier and Pd and Ir which are supported by the carrier, and Pd and Ir are in the form of alloy, respectively. Since Ir is oxidized preferentially to Pd in a lean region, the oxidation of Pd is controlled at an atomic level so that the catalytic activity of Pd can be fully utilized.