Abstract: 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 E1>E2 and E1>0 where E1 is a surface potential of a matrix phase consisting of a cordierite-W composite body relative to the pH of the catalyst solution and E2 is 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.

Abstract: (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.

Abstract: 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.

Abstract: 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 E1>E2 and E1>0 where E1 is a surface potential of a matrix phase consisting of a cordierite-W composite body relative to the pH of the catalyst solution and E2 is 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.

Abstract: 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 10 which are channels for fluid and a peripheral wall 12 which covers at least the circumference of said lattice walls 11. The outer peripheral portion 112 of said lattice walls 11 located in the vicinity of said peripheral wall 12 (area B) contain a densified portion of smaller porosity than that of an inner peripheral portion 111, of said lattice walls 11, which is located inside said outer peripheral portion 112 (area A).

Abstract: 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 10 which are channels for a fluid and a peripheral wall 12 which covers at least the circumference of said lattice walls 11.

Abstract: 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.

Abstract: To provide a ceramic catalyst having both promoter activity and heat resistance at a small amount of promoter component and also having a low pressure drop and a low heat capacity, a noble metal as a catalyst component and at least two layers of promoter components having oxygen storage capacities are supported on a ceramic carrier which is prepared by replacing a part of component element of the ceramic material such as cordierite to enable to support a catalyst component directly thereon. The outermost layer consists of a promoter component having the highest heat resistance, and the innermost layer consists of a promoter component having the highest oxygen storage capacity, which improve heat resistance without increasing an amount of supported promoter component.

Abstract: A ceramic carrier and ceramic catalyst body used as NOx 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 NOx storage materials. The diffusion-inhibiting layer is composed of a ceramic material such as Y2O3, NiO or CeO2 which does not react with alkali metals or alkaline earth metals at temperatures of up to 1000° C. and has a melting point of higher than 1000° 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.

Abstract: This invention aims at providing a direct support ceramic support having less degradation of a catalyst due to thermal durability, and capable of keeping a high catalyst performance for a long time and suppressing a change of characteristics of a substrate ceramic. According to the invention, one or more kinds of constituent elements of a substrate ceramic such as cordierite are replaced by an element such as W to form a ceramic body having at least one kind of elements and fine pores each capable of directly supporting a catalyst component. These elements or fine pores are arranged at only an outermost surface layer portion (a depth corresponding to 1,000 unit crystal lattices or below) of the substrate ceramic. A catalyst body undergoing less thermal degradation and having small influences on the characteristics of the substrate ceramic is thus obtained.

Abstract: 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.

Abstract: 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. The structural body comprises lattice walls formed by a large number of cells which are channels for a fluid and a peripheral wall which covers at least the circumference of the lattice walls. The outer peripheral portion of the lattice walls located in the vicinity of the peripheral wall (area B) contains a densified portion of smaller porosity than that of an inner peripheral portion, of the lattice walls, which is located inside the outer peripheral portion (area A).

Abstract: There is provided a cordierite honeycomb structural body that allows the thickness of the cell walls to be reduced and heat capacity to be decreased by improving the fluidity of the molding material when passing through a mold for extrusion molding while maintaining the shape retention of the molding material. A water-soluble cellulose ether is used as a binder that is added to a cordierite-converted starting material. This water-soluble cellulose ether contains methoxyl groups substituted for the cellulose hydroxyl groups within the range of a substitution rate of 27.5 to 31.5%, does not contain hydroxypropoxyl groups and hydroxyethoxyl groups in an amount greater than the amount of unavoidable impurities (0.1 wt %), and has a viscosity in a 2 wt % aqueous solution at 20° C. of less than 8000 centipoise.

Abstract: In a catalyst body using a direct support, this invention provides a ceramic catalyst body capable of adjusting catalyst performance in accordance with intended objects such as prevention of deactivation of a main catalyst component when an sub catalyst component is used, or improvement of initial purification performance. When both main catalyst component and sub catalyst component are supported on a ceramic support capable of directly supporting the catalyst components, the invention first supports a catalyst metal as a main catalyst such as Pt, for example, and then supports the sub catalyst such as CeO2 on the main catalyst. The main catalyst is thus prevented from being involved in the grain growth of the sub catalyst, and becomes a catalyst body that does not easily undergo thermal deactivation. The ceramic support uses cordierite, a part of the constituent elements of which are replaced, so that the replacing elements so introduced can directly support the catalyst components.

Abstract: The present invention provides a ceramic catalyst body having low thermal capacity and low pressure loss, is capable of demonstrating various catalytic actions according to the application, and has high catalyst performance and practical usefulness.

Abstract: A catalyst ceramic body employing a directly supporting carrier, wherein particle growth due to aggregation of the catalyst particles during loading of the catalyst is suppressed to yield fine particles, thereby improving the purification performance. According to the invention, the base material is cordierite with a portion of its constituent elements substituted, and when a catalyst component such as Pt is to be supported on a ceramic carrier capable of directly supporting a catalyst component on the introduced substituting elements, a precursor for the Pt is loaded and then sintered in a reducing atmosphere. Using a reducing atmosphere allows the metallization temperature to be as low as about 400° C., thereby reducing thermal vibration and suppressing aggregation in order to achieve an effect of reducing the mean particle size of the catalyst to about 100 nm or smaller.

Abstract: The invention provides a gas concentration detection element that can prevent the drop of catalytic activity due to thermal aggregation of catalyst particles under high temperature conditions, can maintain a stable output for a long time and can be easily produced at a low production cost. A reference electrode 12 is formed on an inner surface of a cup-like oxygen ion conductive solid electrolyte 11 and a detection electrode 13 is formed on its outer surface to constitute a gas concentration detection element 1 for detecting a specific gas component in a measured gas. A catalyst layer 15 is constituted by directly supporting a catalyst component on ceramic support particles, such as particles of element-substituted cordierite, through a chemical bond so that both bonding strength and durability can be improved.

Abstract: The present invention has an object to obtain a ceramic body that can support a required amount of catalyst component, without lowering the characteristics such as strength, being manufactured without forming a coating layer and providing a high performance ceramic catalyst body that is excellent in practical utility and durability.

Abstract: The present invention provides a ceramic carrier and a ceramic catalyst which have NOx absorbent capacity, low heat capacity, low pressure loss and high practical value.

Abstract: It is an object of the present invention to provide a ceramic catalyst body with a better catalyst performance by using a ceramic carrier capable of directly supporting a catalyst component.