摘要:
The object of the present invention is to provide an exhaust gas purifying catalyst that can achieve high purification performance while suppressing H2S emissions. The object is solved by an exhaust gas purifying catalyst in which the lower layer of the catalyst coating layer comprises a ceria-zirconia composite oxide having a pyrochlore-type ordered array structure, in which the ceria-zirconia composite oxide contains at least one additional element selected from the group consisting of praseodymium, lanthanum, and yttrium at 0.5 to 5.0 mol % in relation to the total cation amount, and the molar ratio of (cerium+additional element):(zirconium) is within the range from 43:57 to 48:52.
摘要:
An object of the present invention is to provide an exhaust gas purification catalyst which can exhibit high durability and warm-up performance. The present invention relates to an exhaust gas purification catalyst comprising a substrate and a catalyst coating layer formed on the substrate, wherein the catalyst coating layer comprises catalyst particles, the catalyst coating layer having an upstream region extending by 40 to 60% of the entire length of the substrate from an upstream end of the catalyst in the direction of an exhaust gas flow and a downstream region corresponding to the remainder portion of the catalyst coating layer, the composition of the catalyst particle of the upstream region being different from that of the downstream region. The upstream region in the direction of an exhaust gas flow has a structure where a void is included in a large number, and furthermore high-aspect-ratio pores having an aspect ratio of 5 or more account for a certain percentage or more of the whole volume of voids. Thus, the exhaust gas purification catalyst exhibits enhanced purification performance.
摘要:
An catalyst for purifying exhaust gas comprising an OCS material that has sufficient heat resistance and achieves a favorable balance between the oxygen storage volume and the oxygen absorption/release rate includes an catalyst for purifying exhaust, which has a substrate and a catalyst coating layer formed on the substrate, wherein the catalyst coating layer comprises a ceria-zirconia-based composite oxide having a pyrochlore structure in an amount of 5 to 100 g/L based on the volume of the substrate, the ceria-zirconia-based composite oxide has a secondary particle size (D50) of 3 μm to 7 μm, and the ceria-zirconia-based composite oxide optionally contains praseodymium.
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 oxygen adsorbent that includes Ln2O2SO4, wherein Ln represents a rare earth element, and a ceria composite oxide, and an exhaust gas purifying catalyst that includes the oxygen adsorbent.
摘要:
In order to provide an exhaust gas purifying catalyst having improved heat resistance and OSC, a metal oxide particle, and a production process of the metal oxide particle, a metal oxide particle having a core (1) where the total molar number of alumina and silica is larger than the molar number of ceria, and a surface layer (2) where the molar number of ceria is larger than the total molar number of alumina and silica is provided. Further, an exhaust gas purifying catalyst comprising the metal oxide particle and a noble metal supported on the metal oxide particle; and a production process of the metal oxide particle are provided.
摘要:
There is provided an oxygen storage/release material using a rare earth oxysulfate or oxysulfide, which has a high oxygen storage/release capacity even at lower temperatures. The oxygen storage/release material of the present invention comprises a compound consisting of Pr2O2SO4 and/or Pr2O2S and at least one metal selected from the group consisting of Pt, Rh and Fe supported thereon.
摘要翻译:提供了使用稀土氧硫酸盐或氧硫化物的氧气储存/释放材料,即使在较低温度下也具有高的储氧/释放能力。 本发明的储氧/释放材料包括由Pr 2 O 2 SO 4和/或Pr 2 O 2 S组成的化合物和至少一种选自Pt,Rh和Fe所载的金属。
摘要:
The present invention provides a catalyst support powder 3 comprising ceria and zirconia, wherein the ratio of the molar fraction (mol %) of ceria on the support powder surface as measured by the X-ray photoelectron spectroscopy to the molar fraction (mol %) of ceria in the raw material is from 1.0 to 1.5. Further, the present invention provides an exhaust gas purifying catalyst 5 comprising the catalyst support powder 3 and platinum 4 supported thereon.
摘要:
A catalyst 10 for purifying emission gas including a substrate 12, and on the substrate 12, a first catalyst layer 14 including a cerium oxide-zirconia based composite support supporting Pt or Pd, a second catalyst layer 16 including a support containing zirconia as a main component that supports Rh, and a diffusion barrier layer 18 interposed between the first catalyst layer 14 and the second catalyst layer 16 and containing metal oxide whose electronegativity is lower than that of Ce.
摘要:
In order to provide an exhaust gas purifying catalyst having improved heat resistance and OSC, a metal oxide particle, and a production process of the metal oxide particle, a metal oxide particle having a core (1) where the total molar number of alumina and silica is larger than the molar number of ceria, and a surface layer (2) where the molar number of ceria is larger than the total molar number of alumina and silica is provided. Further, an exhaust gas purifying catalyst comprising the metal oxide particle and a noble metal supported on the metal oxide particle; and a production process of the metal oxide particle are provided.