Denso Corporation

Nippon Soken, Inc.

Other

National Institute of Advanced Industrial Science and Technology

Denso Corpora Tion

Japan Spectroscopic Co., Ltd.

Tomohiko Nakanishi

Kazuhiko Koike

Tomomi Hase

Masakazu Tanaka

Kazuhiro Inoguchi

Mitsuru Asano

Masanori Yamada

Yosiyasu Andou

Miho Ito

Tosiharu Kondo

Takumi Suzawa

Takashi Kondo

Jun Hasegawa

Kunio Okamoto

Keiji Ito

Hideki Kita

Kojiro Tokuda

Takeshi Ueda

Shunkichi Ueno

Naoki Kondo

Jayaseelan Daniel Doni

Hiromi Sano

Keiichi Yamada

Takatoshi Shinyoshi

Yoshihide Segawa

Takao Tsuda

Shuzo Kanzaki

Kensuke Takizawa

Yoichi Kadota

Hideaki Ueno

Tatsuki Ohji

Koichi Mochizuki

Daido Ishii

Kentaro Makino

Kiyokatsu Hibi

Toyohide Takeuchi

Kazushige Uchiyama

Takeshi Yoshii

Yuichi Kobayashi

A porous honeycomb structure including multiple co-catalyst particles and multiple inorganic binder particles of smaller particle diameter than the co-catalyst particles. Each co-catalyst particle is comprised of a ceria-zirconia solid solution. The inorganic binder particles reside between the co-catalyst particles. In the honeycomb structure, an exposure fraction of the co-catalyst particles from the inorganic binder particles on a cross-section of the honeycomb structure is within a range of 3 to 10%.

Porous honeycomb structure and producing the same

A method of manufacturing a perovskite catalyst composed of perovskite oxide includes mixing step, firing step and acid-treating step. In the mixing step, an A-site material and a B-site material are mixed at a stoichiometric ratio such that the A-site is increased, compared to that of a theoretical composition ABOof perovskite oxide in which a ratio of A-site and B-site is 1:1. In the firing step, the obtained mixed powder is fired. In the acid-treating step, the obtained fired powder is acid-treated with acid of pH 2 or more and less than pH 7.

Perovskite catalyst and method of manufacturing the same

The present invention provides a needle-shaped ceramic body and needle-shaped ceramic catalyst body in which a base material is a high specific surface area porous cordierite body that is stable at high temperatures, and also provides methods of producing this needle-shaped ceramic body and needle-shaped ceramic catalyst body. The present invention relates to a needle-shaped ceramic body and needle-shaped ceramic catalyst body in which a base material is a high temperature-stable, high specific surface area porous cordierite body comprising a porous structure having a prescribed porosity and formed of a needle-shaped cordierite crystal phase, and further relates to methods of producing this needle-shaped ceramic body and needle-shaped ceramic catalyst body, and by using porous cordierite constituted of needle-shaped crystals as a catalyst-supporting honeycomb structure, the present invention is able to inhibit sintering-induced reduction in the specific surface area. Since a honeycomb can be directly produced as the cordierite sinter itself, an inexpensive product can be provided through the simplifying the prior-art step of coating the interior of the honeycomb.

Needle-shaped ceramic body, needle-shaped ceramic catalyst body and method for producing same

A needle-shaped ceramic body having as its base material a cordierite porous body having a high specific surface area and superior thermal shock resistance, and a needle-shaped catalyst-ceramic body are provided. The present invention relates to a needle-shaped ceramic body having as its base material a needle-shaped cordierite in which the tips thereof are rounded, a needle-shaped catalyst-ceramic body loaded with a catalyst, and a method of production of a ceramic body in which a portion of a raw material (fluoride) gasified by a reaction between raw materials is grown into a needle like shape on the metal catalyst (Fe), wherein the tips of needle-shaped particles are rounded, using a vapor-liquid-solid (VLS) reaction, in a raw material burning process. A honeycomb structure composed of the needle-shaped ceramic for supporting a catalyst is provided, in which decreases in specific surface area caused by sintering can be inhibited, and it enables early catalyst activation due to the low thermal capacity, and has low pressure loss.

Ceramic support capable of supporting catalyst, catalyst-ceramic body and processes for producing same

A formed article is made of cordierite. The cordierite has a plurality of domains and a plurality of crystal grains placed in each domain to form a domain structure. The crystal grains in each domain are substantially aligned in the same direction, and an average size of the domains ranges from 40 &#x3bc;m to 150 &#x3bc;m. The article of cordierite is formed in a honeycomb structure having a plurality of cell walls arranged in a honeycomb form, and a plurality of cells divided by the cell walls are formed. The article of cordierite has a porosity ranging from 36% to 38%, a coefficient of linear thermal expansion equal to or lower than 0.2&#xd7;10/K and a mechanical strength equal to or higher than 60&#xd7;10Pa.

Formed article of cordierite and method for manufacturing the formed article

A ceramic support capable of supporting a catalyst comprising a ceramic body having fine pores with a diameter or width up to 1000 times the ion diameter of a catalyst component to be supported on the surface of the ceramic body, the number of the fine pores being not less than 1&#xd7;10pores per liter, is produced by introducing oxygen vacancies or lattice defects in the cordierite crystal lattice or by applying a thermal shock to form fine cracks.

Ceramic support capable of supporting a catalyst, a catalyst-ceramic body and processes for producing same

A ceramic body that can support a required amount of catalyst component, without lowering the characteristics such as strength, manufactured without forming a coating layer and providing a high performance ceramic catalyst body that is excellent in practical utility and durability. This ceramic body is made by substituting at least one of the constituent elements of cordierite that constitutes the substrate ceramic, for example Al, with W that is the element having an empty orbit in d or f orbit, has high bonding strength and is less susceptible to deterioration since the catalyst component Pt is supported by means of chemical bonding.

Ceramic body and ceramic catalyst body

This invention is directed to providing a high-performance ceramic support being capable of realizing early activation of a catalyst due to direct loading while maintaining the excellent properties of the substrate ceramic, and being less susceptible to heat deterioration, by specifying the kind and combination of optimal replacing elements and the replacing amount and the like. A ceramic support comprising a substrate ceramic containing Mg, Al, Si and O as constituent elements are solid-dissolved therein Ti and W as the second component. The proportion of cordierite crystal having solid-dissolved therein W and Ti is 25 mol % or more, whereby a high-performance directly supporting ceramic support is realized.

Ceramic support

An object of the present invention is to realize low pressure loss and high purification performance in a constitution in which a primary catalyst component and co-catalyst component are loaded onto a ceramic support that allows catalyst components to be loaded directly. According to the present invention, a primary catalyst component in the form of a catalyst precious metal and a co-catalyst component in the form of an oxygen occluding component are loaded on the surface of a honeycomb-shaped ceramic support, including the inner surfaces of pores. As a result of the large loaded amount of co-catalyst component entering inside the pores, the loaded amount of co-catalyst component on the cell wall surfaces is reduced, thereby making it possible to inhibit increases in pressure loss. In addition, since the primary catalyst component and co-catalyst component are in close proximity to each other, catalyst performance is improved.

Ceramic catalyst body

This invention aims at providing a catalyst body exhibiting a lower degradation of a catalyst due to thermal durability and capable of keeping higher catalyst performance for a long time. A catalyst component such as Pt is directly supported by Zr, W, etc, replacing elements inside a support such as Al of cordierite to provide a catalyst body without forming a coating layer. A combination of the catalyst component and the element inside the support is selected so that support strength is greater than 5 eV by simulation using a density functional method. Coarsening of catalyst particles can be suppressed and a high-performance catalyst body excellent in thermal durability can be obtained.

Catalyst body

This invention provides a method for producing a ceramic catalyst body that can directly support a catalyst on a ceramic support without disposing a coating layer on the ceramic support. In the invention, a catalyst solution containing a catalyst component consisting of a negative complex ion resulting from a catalyst precursor is prepared, and a pH of the catalyst solution is adjusted in such a manner as to satisfy the relation E&#x3e;Eand E&#x3e;0 where Eis a surface potential of a matrix phase consisting of a cordierite-W composite body relative to the pH of the catalyst solution and Eis a surface potential of a dispersed phase consisting of compounds other than the cordierite-W composite body. After the ceramic support is brought into contact with the catalyst solution to support the catalyst component, heat-treatment is conducted to bond the matrix phase consisting of the cordierite-W composite body and the catalyst component to support the catalyst on the ceramic support.

Production method of ceramic catalyst body

(i) In a ceramic catalyst body which comprises a ceramic carrier which has a multitude of pores capable of supporting a catalyst directly on the surface of a substrate ceramic and a catalyst supported on the ceramic carrier, a layer containing an anti-evaporation metal such as Rh is formed on the outer surface of catalyst metal particles such as Pt or Rh. The layer containing the anti-evaporation metal protects the catalyst metal and prevents evaporation thereof, thereby suppressing the deterioration; and/or (ii) A ceramic catalyst body is made by having a main catalyst component and a promoter component directly on a ceramic carrier which can directly support the catalyst by substituting a part of the constituent elements of cordierite, and a trap layer is provided in the upstream thereof for trapping sulfur which is a catalyst poisoning component included in the exhaust gas. Since sulfur included in the exhaust gas can be collected by the trap layer, the catalyst poisoning component can be removed from the gas which enters the catalyst, thus preventing catalyst poisoning.

The present invention provides a ceramic honeycomb structural body, and method for preparing the same, which can satisfactorily support a catalyst and can demonstrate superior mechanical strength, even if far thinner walls are used. Said structural body comprises lattice walls formed by a large number of cells which are channels for fluid and a peripheral wall which covers at least the circumference of said lattice walls . The outer peripheral portion of said lattice walls located in the vicinity of said peripheral wall (area B) contain a densified portion of smaller porosity than that of an inner peripheral portion , of said lattice walls , which is located inside said outer peripheral portion (area A).

Ceramic honeycomb structural body and methods of preparing the same

A ceramic carrier and ceramic catalyst body used as NO purification catalysts for lean burn engines, which are inexpensive, exhibit high temperature durability and can maintain their catalytic function for extended periods. The ceramic carrier has a diffusion-inhibiting layer formed on the surface of a cordierite honeycomb structure, to inhibit diffusion of alkali metals, alkaline earth metals, etc. carried as NO storage materials. The diffusion-inhibiting layer is composed of a ceramic material such as Y O , NiO or CeO which does not react with alkali metals or alkaline earth metals at temperatures of up to 1000&deg; C. and has a melting point of higher than 1000&deg; C., and the diffusion-inhibiting layer inhibits diffusion of catalyst components such as potassium into the interior to prevent their reaction with cordierite, so that the durability is greatly enhanced without reducing catalytic performance.

Ceramic carrier and ceramic catalyst body

Growing community of inventors

Kariya, Japan

Tomohiko Nakanishi