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AssigneesToyota Jidosha Kabushiki Kaisha, Kabushiki Kaisha Toyota Chuo Kenkyusho
InventorsYoriko Hasegawa, Mareo Kimura, Naoki Takahashi, Hiromasa Suzuki, Riemi Tanizawa, Kazuaki Sobue
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A catalyst for purifying an exhaust gas includes a support including rutile titania, an NOx storage material including at least on element selected from alkali metals, alkaline-earth metals and rare-earth elements and loaded on the support, and a noble metal loaded on the support. Since the rutile TiO2 and the NOx storage material form a fine composite oxide, the NOx storage material is likely to decompose even when it is subject to the sulfur poisoning, and the NOx storage material easily recovers the NOx storage ability. Therefore, the NOx storage material can be inhibited from the sulfur poisoning, and a high NOx conversion ratio can be maintained even after the service at an elevated temperature.
A NOx storage-and-reduction catalyst for purifying an exhaust gas that is disposed in an exhaust gas of an oxygen-rich atmosphere made by burning an air-fuel mixture whose air-fuel ratio, A/F (air/fuel), is 18 or more, so that NOx in the exhaust gas is stored therein, and whose air-fuel ratio is perturbed from the stoichiometric point to a fuel-rich atmosphere periodically so that the NOx stored therein is released therefrom, thereby carrying out reducing and purifying, said catalyst being characterized by comprising:
A process for manufacturing a catalyst for purifying an exhaust gas characterized by comprising the steps of:
A method for purifying an exhaust gas characterized in that a catalyst for purifying an exhaust gas, comprising a support including rutile titania, a NOx storage material including at least one element selected from the group consisting of alkali metals, alkaline-earth metals and rare-earth elements and loaded on the support, and a noble metal loaded on the support, is disposed in an exhaust gas of an oxygen-rich atmosphere made by burning an air-fuel mixture whose air-fuel ratio, A/F (air/fuel), is 18 or more, so that NOx in the exhaust gas are stored in the NOx storage material, and whose air-fuel ratio is varied from the stoichiometric point to a fuel-rich atmosphere periodically so that the NOx stored in the NOx storage material are released, thereby carrying out reducing and purifying, wherein at least part of said rutile titania and said NOx storage material forms a composite oxide.
A catalyst for purifying an exhaust gas characterized by comprising:
A process for manufacturing a catalyst for purifying an exhaust gas characterized by comprising the steps of:
A method for purifying an exhaust gas characterized in that a catalyst for purifying an exhaust gas, comprising a support including rutile titania, a NOx storage material including at least one element selected from the group consisting of alkali metals and alkaline-earth metals and loaded on the support, and a noble metal loaded on the support, is disposed in an exhaust gas of an oxygen-rich atmosphere made by burning an air-fuel mixture whose air-fuel ratio, A/F (air/fuel), is 18 or more, so that NOx in the exhaust gas are stored in the NOx storage material, and whose air-fuel ratio is varied from the stoichiometric point to a fuel-rich atmosphere periodically so that the NOx stored in the NOx storage material are released, thereby carrying out reducing and purifying, wherein at least part of said rutile titania and said NOx storage material forms a composite oxide.
Dependencies are inferred from the claim text.