Exhaust gas purifying catalyst and exhaust gas purifying method

摘要

An exhaust gas purifying catalyst is formed of a first powder formed of porous particles supporting rhodium (Rh), and a second powder formed of porous particles supporting platinum (Pt) and a nitrogen oxides (NOx)-adsorbing material. The second powder and the first powder are present in a mixed state. In this catalyst, Rh is supported apart from Pt and the NOx adsorbent, so that reduction of the oxidizing performance of Pt is prevented, and so that the problems of poor compatibility between Rh and the NOx adsorbent is eliminated. The catalyst therefore maintains high NOx removing rate not only during an initial period but also after the endurance test.