摘要:
An exhaust gas purification catalyst includes: a lower catalyst layer that contains a ceria-zirconia mixed oxide having 50 to 70 mass % of CeO2 and 5 mass % or more of Pr2O3 and carries at least one of Pt and Pd; and an upper catalyst layer that contains at least zirconia and carries at least Rh, wherein the total amount of CeO2 per liter of the carrier base is 15 to 30 g. Because the amount of CeO2 is small, formation of H2S is suppressed and a high capability of adsorbing and releasing oxygen is brought out in spite of the small amount of CeO2.
摘要:
An exhaust gas purification catalyst includes: a lower catalyst layer that contains a ceria-zirconia mixed oxide having 50 to 70 mass % of CeO2 and 5 mass % or more of Pr2O3 and carries at least one of Pt and Pd; and an upper catalyst layer that contains at least zirconia and carries at least Rh, wherein the total amount of CeO2 per liter of the carrier base is 15 to 30 g. Because the amount of CeO2 is small, formation of H2S is suppressed and a high capability of adsorbing and releasing oxygen is brought out in spite of the small amount of CeO2.
摘要:
A composite oxide with a high oxygen storage capacity is provided without using cerium. The composite oxide is an iron oxide-zirconia composite oxide containing iron, zirconium, and a rare-earth element. The total content of Fe2O3, ZrO2, and an oxide of the rare-earth element is not less than 90 mass %, the content of an iron oxide in terms of Fe2O3 is 10 to 90 mass %, and the absolute value of the covariance COV(Fe, Zr+X) of the composite oxide, which has been baked in the atmosphere at a temperature of greater than or equal to 900° C. for 5 hours or more, is not greater than 20.
摘要:
A catalyst for purification of exhaust gas, in which a noble metal is supported on a metal oxide support, has a basic site content of 1 mmol/L-cat or less, as determined on the basis of an amount of CO2 desorbed per liter of the catalyst as measured by a CO2 temperature-programmed desorption method.
摘要:
An exhaust gas-purifying catalyst includes a support provided with one or more through-holes through which exhaust gas flows, and a catalytic layer supported by the support and containing an oxygen storage material. The exhaust gas-purifying catalyst includes a first section to which the exhaust gas is supplied, and a second section to which the exhaust gas having passed through the first section is supplied. The catalytic layer includes a layered structure of a first catalytic layer containing platinum and/or palladium and a second catalytic layer containing rhodium in the first catalytic section and further includes a third layer containing rhodium in the second section. The second section is smaller in oxygen storage material content per unit volumetric capacity than the first section.
摘要:
An apparatus for purification of exhaust gas comprises: an exhaust gas pipe (2) connected to an internal combustion engine (1); an upstream catalyst (3) arranged at the upstream side of an exhaust gas passage inside the exhaust gas pipe (2); a downstream catalyst (4) which is arranged at the downstream side of the exhaust gas passage inside the exhaust gas pipe (2), and on which nickel and/or iron is supported; and oxidizing gas supply means (5) which is connected to the exhaust gas pipe (2) between the upstream catalyst (3) and the downstream catalyst (4), and which supplies oxidizing gas into the exhaust gas pipe (2).
摘要:
A catalyst for purification of exhaust gas, in which a noble metal is supported on a metal oxide support, has a basic site content of 1 mmol/L-cat or less, as determined on the basis of an amount of CO2 desorbed per liter of the catalyst as measured by a CO2 temperature-programmed desorption method.
摘要:
A composite oxide with a high oxygen storage capacity is provided without using cerium. The composite oxide is an iron oxide-zirconia composite oxide containing iron, zirconium, and a rare-earth element. The total content of Fe2O3, ZrO2, and an oxide of the rare-earth element is not less than 90 mass %, the content of an iron oxide in terms of Fe2O3 is 10 to 90 mass %, and the absolute value of the covariance COV(Fe, Zr+X) of the composite oxide, which has been baked in the atmosphere at a temperature of greater than or equal to 900° C. for 5 hours or more, determined by the following Formulae (1) to (3), is not greater than 20: [ Math . 1 ] R i ( Fe ) = I i ( Fe ) × 100 I i ( Fe ) + I i ( Zr ) + I i ( X ) ( 1 ) R i ( Zr + X ) = { I i ( Zr ) + I i ( X ) } × 100 I i ( Fe ) + I i ( Zr ) + I i ( X ) ( 2 ) COV ( Fe , Zr + X ) = 1 n ∑ i = 1 n [ { R i ( Fe ) - R av ( Fe ) } × { R i ( Zr + X ) - R av ( Zr + X ) } ] ( 3 ) (in the formula, Ii(Fe), Ii(Zr), and Ii(X) respectively represent the ratios of the X-ray intensities of iron, zirconium, and the rare-earth element measured at a measurement point i (where i=1 to n) to the 100% intensities of the respective elements as measured by subjecting the composite oxide to a ray analysis through EPMA (WDX: wavelength dispersive X-ray spectrometry), where Rav(Fe) and Rav(Zr+X) represent the mean values of Ri(Fe) and Ri(Zr+X), respectively, at all measurement points n).
摘要:
An exhaust gas-purifying catalyst includes a support provided with one or more through-holes through which exhaust gas flows, and a catalytic layer supported by the support and containing an oxygen storage material. The exhaust gas-purifying catalyst includes a first section to which the exhaust gas is supplied, and a second section to which the exhaust gas having passed through the first section is supplied. The catalytic layer includes a layered structure of a first catalytic layer containing platinum and/or palladium and a second catalytic layer containing rhodium in the first catalytic section and further includes a third layer containing rhodium in the second section. The second section is smaller in oxygen storage material content per unit volumetric capacity than the first section.
摘要:
The exhaust gas-purifying catalyst includes a substrate provided with one or more through-holes through which exhaust gas flows, and a catalyst layer which is supported by the substrate and contains precious metals and an oxygen storage material. The exhaust gas-purifying catalyst contains a first part to which the exhaust gas is supplied, and a second part to which the exhaust gas having passed through the first part is supplied and is smaller in the content of the oxygen storage material per unit volume than that of the first part.