Double layered exhaust gas purification catalyst
AssigneeToyota Jidosha Kabushiki Kaisha
InventorsYuki Aoki, Takeshi Nobukawa
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Abstract
An exhaust gas purification catalyst has a substrate, a lower catalyst layer that is formed on the substrate and contains at least one of Pd and Pt, and an upper catalyst layer that is formed on the lower catalyst layer and contains Rh. A region that does not contain the upper catalyst layer is disposed on the exhaust gas upstream side of this exhaust gas purification catalyst. The lower catalyst layer includes a front-stage lower catalyst layer on the exhaust gas upstream side and a rear-stage lower catalyst layer on the exhaust gas downstream side. The front-stage lower catalyst layer contains an oxygen storage material.
Claims9
An exhaust gas purification catalyst comprising:
- a substrate;
- a lower catalyst layer that is formed on the substrate and contains at least one of Pd and Pt;
- and
- an upper catalyst layer that is formed on the lower catalyst layer and contains Rh, wherein
- the lower catalyst layer is formed of a front-stage lower catalyst layer disposed on a portion of an exhaust gas upstream side in which the upper catalyst layer is not contained, and a rear-stage lower catalyst layer disposed on an exhaust gas downstream side, and the front-stage lower catalyst layer contains an oxygen storage material, wherein the oxygen storage material contains a CeO2—ZrO2 composite oxide having a pyrochlore phase formed of Ce2Zr2O7.
An exhaust gas purification catalyst comprising:
- a substrate;
- a lower catalyst layer that is formed on the substrate and contains at least one of Pd and Pt;
- and
- an upper catalyst layer that is formed on the lower catalyst layer and contains Rh,
- wherein a region that does not contain the upper catalyst layer is disposed on an exhaust gas upstream side of the exhaust gas purification catalyst, the lower catalyst layer is formed of a front-stage lower catalyst layer disposed on the exhaust gas upstream side and a rear-stage lower catalyst layer disposed on an exhaust gas downstream side, and the front-stage lower catalyst layer contains an oxygen storage material, wherein the oxygen storage material contains a CeO2—ZrO2 composite oxide having a pyrochlore phase formed of Ce2Zr2O7, and
- wherein the front-stage lower catalyst layer is coated over 20 to 35% of the total length of the substrate, the rear-stage lower catalyst layer is coated over 65 to 80% of the total length of the substrate, and the upper catalyst layer is coated over 80 to 90% of the total length of the substrate.
An exhaust gas purification catalyst comprising:
- a substrate;
- a lower catalyst layer that is formed on the substrate and contains at least one of Pd and Pt;
- and
- an upper catalyst layer that is formed on the lower catalyst layer and contains Rh,
- wherein a region that does not contain the upper catalyst layer is disposed on an exhaust gas upstream side of the exhaust gas purification catalyst, the lower catalyst layer is formed of a front-stage lower catalyst layer disposed on the exhaust gas upstream side and a rear-stage lower catalyst layer disposed on an exhaust gas downstream side, and the front-stage lower catalyst layer contains an oxygen storage material, wherein the oxygen storage material contains a CeO2—ZrO2 composite oxide having a pyrochlore phase formed of Ce2Zr2O7, and
- wherein the front-stage lower catalyst layer is exposed to inflowing exhaust gas over 10% to 20% of the total length of the substrate.
Dependencies are inferred from the claim text.