Abstract: Provided is an exhaust gas-purifying catalyst excelling in an exhaust gas-purifying performance. The exhaust gas-purifying catalyst contains a substrate, and a catalyst layer formed on the substrate and containing a precious metal and praseodymium.

Abstract: An exhaust gas purifying catalyst comprises a substrate having a through hole serving as a passage for exhaust gas; and a catalyst coating layer formed on an internal surface of the through hole. The catalyst coating layer contains: a component (i): a precious metal; and a component (ii): at least one of a Zr oxide, a Ce oxide and a ZrCe mixed oxide. On an upstream portion of the passage, an oxide equivalent weight of Zr is within a range of 51-100 wt % of an oxide equivalent weight of Zr and Ce contained in the component (ii). On a downstream portion of the passage, the component (ii) includes at least one of a Ce oxide and a ZrCe mixed oxide in which an oxide equivalent weight of Ce is within a range of 58-100 wt % of an oxide equivalent weight of Zr and Ce contained in the ZrCe mixed oxide.

Abstract: An exhaust gas purifying catalyst comprises a substrate having a through hole serving as a passage for exhaust gas; and a catalyst coating layer formed on an internal surface of the through hole. The catalyst coating layer contains: a component (i): a precious metal; and a component (ii): at least one of a Zr oxide, a Ce oxide and a ZrCe mixed oxide. On an upstream portion of the passage, an oxide equivalent weight of Zr is within a range of 51-100 wt % of an oxide equivalent weight of Zr and Ce contained in the component (ii). On a downstream portion of the passage, the component (ii) includes at least one of a Ce oxide and a ZrCe mixed oxide in which an oxide equivalent weight of Ce is within a range of 58-100 wt % of an oxide equivalent weight of Zr and Ce contained in the ZrCe mixed oxide.

Abstract: An exhaust gas purifying catalyst exhibiting high catalytic performance and restraining an amount of noble metals used is provided. An exhaust gas purifying catalyst has a catalyst substrate and a catalyst coating layer formed on the catalyst substrate. The catalyst coating layer has a layered structure including an inside layer containing (a-1) Pd, (a-2) Pt, and (a-3) an inorganic oxide, and an outside layer containing (b-1) a noble metal and (b-2) an inorganic oxide. A part of (a-3) the inorganic oxide carries Pd and Pt so that a weight ratio Pd/Pt is within a range of 8 to 12, whereas the other part of (a-3) the inorganic oxide carries Pd and Pt so that a weight ratio Pd/Pt is within a range of 4 to 6 or within a range of 18 to 22.

Abstract: An exhaust gas purifying catalyst having a good ignition performance is provided. The exhaust gas purifying catalyst 1 includes a catalyst substrate 3 and a catalyst coating layer 5 which contains a noble metal and a refractory inorganic oxide and is formed on the catalyst substrate. The exhaust gas purifying catalyst is characterized in that the catalyst coating layer 5 includes an upstream portion 11 located upstream and a downstream portion 13 located downstream in a flow direction of an exhaust gas. The upstream portion 11 has a layered structure including an upstream portion inside layer 17 and an upstream portion outside layer 15. The upstream portion inside layer contains a cerium-zirconium composite oxide in which a relative proportion of CeO2 is 50 to 95 wt %, as the refractory inorganic oxide, and the upstream portion outside layer 15 and the downstream portion 13 contain a cerium-zirconium composite oxide in which a relative proportion of ZrO2 is 50 to 95 wt %, as the refractory inorganic oxide.

Abstract: This is to provide a catalyst for purifying exhaust gases, catalyst which are good in terms of the purifying performance.

Abstract: A high exhaust gas-purifying performance is achieved. An exhaust gas-purifying catalyst includes a substrate, a lower layer covering the substrate and including an oxygen storage material and palladium, and an upper layer covering the lower layer and including rhodium and a carrier supporting it. The lower layer is rhodium-free. The upper layer has an oxygen storage capacity lower than that of the lower layer.

Abstract: An exhaust gas purifying catalyst exhibiting high catalytic performance and restraining an amount of noble metals used is provided. An exhaust gas purifying catalyst has a catalyst substrate and a catalyst coating layer formed on the catalyst substrate. The catalyst coating layer has a layered structure including an inside layer containing (a-1) Pd, (a-2) Pt, and (a-3) an inorganic oxide, and an outside layer containing (b-1) a noble metal and (b-2) an inorganic oxide. A part of (a-3) the inorganic oxide carries Pd and Pt so that a weight ratio Pd/Pt is within a range of 8 to 12, whereas the other part of (a-3) the inorganic oxide carries Pd and Pt so that a weight ratio Pd/Pt is within a range of 4 to 6 or within a range of 18 to 22.

Abstract: An exhaust gas purifying catalyst is provided which includes a catalyst substrate and a catalyst coating layer. The catalyst coating layer is formed on the catalyst substrate and contains a noble metal and a refractory inorganic oxide. The catalyst coating layer has a layered structure including an A-layer and a B-layer. The A-layer contains Pd and Pt as the noble metal in a weight ratio of 3:1 to 20:1. The B-layer includes Rh as the noble metal.

Abstract: A high exhaust gas-purifying efficiency is achieved. An exhaust gas-purifying catalyst includes a substrate, an oxygen storage layer covering the substrate and including an oxygen storage material, and a catalytic layer covering the oxygen storage layer and including palladium, rhodium and a carrier supporting them, the catalytic layer having a precious metal concentration higher than that of the oxygen storage layer.

Abstract: Decreasing HC emission is made possible. An exhaust gas-purifying catalyst includes a substrate, a hydrocarbon-adsorbing layer covering the substrate, and a catalytic layer covering the hydrocarbcn-adsorbing layer. The catalytic layer includes a layered structure of a first catalytic layer including a precious metal and a carrier supporting it, and a second catalytic layer including the same precious metal as the precious metal of the first catalytic layer and a carrier supporting it and having a concentration of the precious metal higher than that in the first catalytic layer.

Abstract: An exhaust gas purifying catalyst includes a catalyst substrate and a catalyst coating layer containing a noble metal and a refractory inorganic oxide. The catalyst coating layer includes an upstream portion located upstream and a downstream portion located downstream in a flow direction of an exhaust gas. The upstream portion has a layered structure including an upstream portion inside layer containing a cerium-zirconium composite oxide in which a relative proportion of CeO2 is 50 to 95 wt %, as the refractory inorganic oxide and an upstream portion outside layer containing a cerium-zirconium composite oxide in which a relative proportion of ZrO2 is 50 to 95 wt %, as the refractory inorganic oxide. The upstream portion outside layer and the downstream portion contain Rh as the noble metal, and an amount of Rh contained in the upstream portion outside layer is larger than an amount of Rh contained in the downstream portion.

Abstract: A hexagonal-cell honeycomb catalyzer is for purifying an exhaust gas. The catalyzer comprising a support that has a plurality of cells and a purification layer that has an HC absorption layer and a three-way catalyst layer. The HC absorption layer is formed on the honeycomb-formed surface of each wall of the support. The three-way catalyst layer is formed on the surface of the HC absorption layer. Provided that the HC absorption layer has a thickness a1 and the three-way catalyst layer has a thickness b1 at a thin portion of the purification layer of which thickness is minimum and the HC absorption layer has a thickness a2 and the three-way catalyst layer has a thickness b2 at a thick portion of the purification layer of which thickness is maximum, a ratio of a1/b1 and a ratio of a2/b2 are both within a range of 1/20 to 5/1.

Abstract: This is to provide a catalyst for purifying exhaust gases, catalyst which are good in terms of the purifying performance.

Abstract: An exhaust gas-purifying catalyst includes a support substrate, a catalyst support layer formed on the support substrate and containing a composite oxide of a rare earth element and zirconium, and a catalytic metal supported by the catalyst support layer. In this catalyst, all oxides containing the rare earth element are composite oxides of the rare earth element and zirconium in which the atomic ratio of zirconium to the rare earth element is 0.8 or more.

Abstract: A catalyst for purifying exhaust gases exhibits not only effective purifying characteristics even in a low temperature range such as immediately after an engine starts but also high exhaust gas purifying ability. In the catalyst for purifying exhaust gases of a first aspect of the invention, HC adsorbed at low temperature are released at high temperature and the released HC are purified by a catalyst metal. This catalyst for purifying exhaust gases has an excellent advantage in purifying HC at low temperature as well as excellent exhaust gas purifying ability.

Abstract: An exhaust gas purifying catalyst comprises a substrate having a through hole serving as a passage for exhaust gas; and a catalyst coating layer formed on an internal surface of the through hole. The catalyst coating layer contains: a component (i): a precious metal; and a component (ii): at least one of a Zr oxide, a Ce oxide and a ZrCe mixed oxide. On an upstream portion of the passage, an oxide equivalent weight of Zr is within a range of 51-100 wt % of an oxide equivalent weight of Zr and Ce contained in the component (ii). On a downstream portion of the passage, the component (ii) includes at least one of a Ce oxide and a ZrCe mixed oxide in which an oxide equivalent weight of Ce is within a range of 58-100 wt % of an oxide equivalent weight of Zr and Ce contained in the ZrCe mixed oxide.

Abstract: A catalyst for purifying exhaust gases, which enables the HC-purification performance to be further improved by suitably arranging an HC-adsorbent. The catalyst includes a coating layer which is composed of alumina and zeolite, and carries a noble metal. The weight ratio of alumina and zeolite in the coating layer ranges from 5:1 to 1:1. Zeolite adsorbs HC when exhaust gases are in a low temperature region, and HC desorbed from zeolite is oxidized and purified with the noble metal.

Abstract: A catalyst for purifying exhaust gases exhibits not only effective purifying characteristics even in a low temperature range such as immediately after an engine starts but also high exhaust gas purifying ability. In the catalyst for purifying exhaust gases of a first aspect of the invention, HC adsorbed at low temperature are released at high temperature and the released HC are purified by a catalyst metal. This catalyst for purifying exhaust gases has an excellent advantage in purifying HC at low temperature as well as excellent exhaust gas purifying ability.

Abstract: A catalyst for purifying exhaust gases exhibits not only effective purifying characteristics even in a low temperature range such as immediately after an engine starts but also high exhaust gas purifying ability. In the catalyst for purifying exhaust gases of a first aspect of the invention, HC adsorbed at low temperature are released at high temperature and the released HC are purified by a catalyst metal. This catalyst for purifying exhaust gases has an excellent advantage in purifying HC at low temperature as well as excellent exhaust gas purifying ability.