Toyota Jidosha Kabushiki Kaisha

Cataler Corporation

Kabushiki Kaisha Toyota Chuo Kenkyusho

Kae Konishi

Hiromasa Suzuki

Masahide Miura

Akira Morikawa

Akihiko Suda

Toshitaka Tanabe

Isao Chinzei

Akiya Chiba

Kosuke Iizuka

Takeshi Nobukawa

Takahiro Hayashi

Kimitoshi Sato

Naoki Kumatani

A ceria-zirconia-based composite oxide containing a composite oxide of ceria and zirconia is provided, in which primary particles having a particle diameter of 1.5 to 4.5 &#x3bc;m account for, on a particle number basis, at least 50% of all primary particles in the ceria-zirconia-based composite oxide, and the molar ratio of cerium to zirconium in the ceria-zirconia-based composite oxide is between 43:57 and 55:45.

Ceria-zirconia-based composite oxide and method for producing same, and exhaust gas purification catalyst including ceria-zirconia-based composite oxide

A ceria-zirconia composite oxide includes at least one of lanthanum, yttrium, and praseodymium. A rate of a total content of the at least one rare earth element to a total content of cerium and zirconium is 0.1 at % to 4.0 at %. A content of the rare earth element present in near-surface regions, which are at a distance of less than 50 nm from surfaces of primary particles of the ceria-zirconia composite oxide, accounts for 90 at % or more of the total content of the rare earth element. An average particle size of the primary particles of the ceria-zirconia composite oxide is 2.2 &#x3bc;m to 4.5 &#x3bc;m. After a predetermined durability test, the intensity ratio I(14/29) of a diffraction line at 2&#x3b8;=14.5&#xb0; to a diffraction line at 2&#x3b8;=29&#xb0; and the intensity ratio I(28/29) of a diffraction line at 2&#x3b8;=28.5&#xb0; to the diffraction line at 2&#x3b8;=29&#xb0; respectively satisfy the following conditions:(14/29)&#x2265;0.02, and(28/29)&#x2264;0.08.

Ceria-zirconia composite oxide, method for producing the same, and catalyst for purifying exhaust gas using the ceria-zirconia composite oxide

A ceria-zirconia-based composite oxide including a composite oxide containing ceria and zirconia, wherein the ceria-zirconia-based composite oxide contains at least one member selected from the group consisting of praseodymium, lanthanum, and yttrium in an amount of 0.5 to 5.0 mol % relative to a total amount of the cations contained in the ceria-zirconia-based composite oxide, where the ratio of the content of both cerium and the at least one member selected from the group consisting of praseodymium, lanthanum, and yttrium in the ceria-zirconia-based composite oxide to the content of zirconium therein ([cerium and the at least one member selected from the group consisting of praseodymium, lanthanum, and yttrium]:[zirconium]) is in the range of 43:57 to 48:52 by mole ratio.

Ceria-zirconia-based composite oxide and method for producing same, and catalyst for exhaust gas purification including ceria-zirconia-based composite oxide

A catalyst support for purification of exhaust gas includes a porous composite metal oxide, the porous composite metal oxide containing alumina, ceria, and zirconia and having an alumina content ratio of from 5 to 80% by mass, wherein after calcination in the air at 1100&#xb0; C. for 5 hours, the porous composite metal oxide satisfies a condition such that standard deviations of content ratios (as at % unit) of aluminum, cerium and zirconium elements are each 19 or less with respect to 100 minute areas (with one minute area being 300 nm in length&#xd7;330 nm in width) of the porous composite metal oxide, the standard deviation being determined by energy dispersive X-ray spectroscopy using a scanning transmission electron microscope equipped with a spherical aberration corrector.

Catalyst support for purification of exhaust gas, catalyst for purification of exhaust gas using the same, and method for producing the catalyst support for purification of exhaust gas

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Nagakute, Japan

Kae Konishi