LNT LAMINATE CATALYST FOR GASOLINE LEAN BURN ENGINE, AND EXHAUST GAS CLEANER THEREWITH

• Main Authors: FUJIMURA YUDAI, OMATA HIDEYA, TAN ISAO, FUKUTOMI SHUNSUKE, SASAKI KOKICHI
• Format: Patent
• Language: English; Japanese
• Published: 13.09.2021
• Subjects: BLASTING; CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOIDCHEMISTRY; ENGINE PLANTS IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNALCOMBUSTION ENGINES; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES ORENGINES IN GENERAL; HEATING; LIGHTING; MACHINES OR ENGINES IN GENERAL; MECHANICAL ENGINEERING; PERFORMING OPERATIONS; PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL; SEPARATION; STEAM ENGINES; THEIR RELEVANT APPARATUS; TRANSPORTING; WEAPONS

To provide an LNT laminate catalyst for gasoline lean burn engines capable of furthermore heightening NOx occlusion rate and capable of developing higher NOx purification rate, and an exhaust gas cleaner therewith.SOLUTION: An LNT laminate catalyst for gasoline lean burn engines comprises: a substrate 11; a first catalyst layer L1 containing ceria/alumina-based host particles carrying Pt and Pd as well as BaO; and a second catalyst layer R1 containing ceria/alumina-based host particles carrying Pt and Rh, in which a content of Pt contained in the first catalyst layer L1 is 0.45 to 0.85 mass% in terms of metal relative to a total solid content of the first catalyst layer L1, among the Pt contained in the first catalyst layer L1, content ratios of depth regions L1a, L1b are 88 mass% to 90 mass%, a content ratio of the depth region L1c is 10 to 12 mass%, a content ratio of Ba contained in the first catalyst layer L1 is 4 to 11 mass% in terms of oxide relative to a total amount of the first catalyst layer L1, and the second catalyst layer R1 does not substantially contain Ba.SELECTED DRAWING: Figure 1 【課題】ＮＯｘ吸蔵率がより高められ、より高いＮＯｘ浄化率を発現可能な、ガソリンリーンバーンエンジン用ＬＮＴ積層触媒、及びこれを用いた排ガス浄化装置等を提供する。【解決手段】基材１１と、Ｐｔ及びＰｄ並びにＢａＯを担持したセリアアルミナ系母材粒子を含む第１触媒層Ｌ１と、Ｐｔ及びＲｈを担持したセリアアルミナ系母材粒子を含む第２触媒層Ｒ１とを備え、第１触媒層Ｌ１に含まれるＰｔの含有量が第１触媒層Ｌ１の固形分総量に対して金属換算で０．４５〜０．８５質量％であり、第１触媒層Ｌ１に含まれるＰｔのうち、深さ領域Ｌ１ａ，Ｌ１ｂの含有割合が８８質量％〜９０質量％であり、深さ領域Ｌ１ｃの含有割合が１０〜１２質量％であり、第１触媒層Ｌ１に含まれるＢａの含有量が第１触媒層Ｌ１の総量に対して酸化物換算で４〜１１質量％であり、第２触媒層Ｒ１はＢａを実質的に含まない、ガソリンリーンバーンエンジン用ＬＮＴ積層触媒。【選択図】図１