| 摘要 |
PROBLEM TO BE SOLVED: To produce a catalyst for exhaust-gas purification superior in the heat resistance, by providing an NOx-occlusion substance for repeating the stable absorption-desorption of NOx even at a high temperature. SOLUTION: This catalyst carries as an NOx-occlusion substance an inorganic compound having a chemical structure reversibly changeable consequently upon NOx absorption on the lean side and NOx desorption on the rich side, and in the catalyst K2WO4, KtaO3, or KVO3 is carried as the NOx-occlusion substance. The NOx-occlusion substance is carried preferably on a carrier comprising alumina, titania, silica, silica-alumina, zirconia, zeolite, ceria, or a mixture thereof, and further a catalytic metal comprising Pt, Pd, Au, Ag, Ph, Ir or a mixture thereof is carried on the carrier. |
