Abstract: This invention provides a honeycomb catalyst having an excellent purification efficiency and a small pressure loss and can be mounted even in a limited space, the honeycomb catalyst comprising: porous partition walls 4 having plural pores 25, which are arranged to form plural cells 3 allowing communication between two end faces; plugging portions being arranged to plug the cells 3 in one of the end faces; and catalytically active components 5, 15 loaded on surfaces of partition walls 4 and inner surfaces of pores 25, wherein many catalytically active component-loading pores 35 through which a gas can pass are formed in partition walls 4, and a ratio of a mass (MW) of the catalytically active component loaded on the surfaces of partition walls 4 to a mass (MP) of the catalytically active component 5 loaded on the inner surfaces of the pores 25 is (MW):(MP)=1:3 to 3:1.

Abstract: There is disclosed a catalytic body with purifying efficiency and smaller pressure loss and its manufacturing method. Provided is a catalytic body wherein a porous honeycomb structure including partition walls defining a plurality of cells acting as fluid passages which extend through the honeycomb structure from one end surface to the other end surface thereof is formed of at least one type of (a) a catalytic substance and (b) a substance including an oxide and at least one type of noble metal carried on the oxide. The catalytic converter is characterized in that (c) 10% or more of a plurality of cells are plugged by plugging parts formed at one ends or in the middles of passages, that (d) the average pore diameter of the honeycomb structure is 10 ?m or more, or that (e) the porosity is 40% or more.

Abstract: There are disclosed a honeycomb catalytic body to which a wall flow structure is applied so that a fluid such as an exhaust gas passes through a partition wall twice or more, and a honeycomb structure for use as a catalyst carrier of the honeycomb catalytic body in which a pore characteristic and the like are appropriately adjusted as the catalytic body. In a honeycomb structure 11 including porous partition walls 4 arranged so as to form a plurality of cells 3 which communicate between two end surfaces of the honeycomb structure and having a large number of pores; and plugging portions 10 arranged so as to plug at least a part of the plurality of cells 3 at any position in a length direction of the cells, an average maximum image distance of the partition walls is larger than 40 ?m, and the plugging portions 10 are arranged so that at least a part of a fluid which has entered the cells from one end surface passes through the partition wall 4 twice or more, and is then discharged from the other end portion.

Abstract: A catalytic converter having an excellent purification efficiency and small pressure loss and a method for producing the same is provided. A catalytic converter comprises a catalyst coating layer which is coated on the surface of the partition walls of the honeycomb structural body having partition walls which divide and form a plurality of cells functioning as fluid passages.

Abstract: A system for exhaust gas purification includes at least one adsorbent capable of adsorbing harmful substances such as hydrocarbons and the like in exhaust gas and at least one catalyst containing a catalyst component, capable of reducing said harmful substances, both provided at an in-line position of exhaust pipe of internal combustion engine. In the system, the hydrocarbons, etc. in the exhaust gas emitted during cold engine start up of internal combustion engine are adsorbed by the adsorbent and the adsorbed hydrocarbons, etc. are desorbed from the adsorbent with the temperature rise of the adsorbent caused by the heat of the exhaust gas and are burnt on the catalyst. The adsorbent contains a H type ?-zeolite having a SiO2/Al2O3 ratio of 100 or more and can maintain good adsorption capability even when exposed to an exhaust gas of 750° C. or more form an internal combustion engine.

Abstract: A honeycomb structure having porous partition walls having a large number of pores, formed so as to produce a plurality of cells each extending between the two ends of the honeycomb structure, and plugged portions formed so as to plug the cells at either one end of the honeycomb structure or at the insides of the cells, wherein the honeycomb structure has the partition walls of a permeability of 7×10?12 to 4×10?8 m2. The honeycomb structure can provide a honeycomb catalyst structure which is superior in purification efficiency, is low in pressure loss and can be mounted even in a limited space.

Abstract: A catalyst body includes a catalytic layer containing an alkali metal and/or an alkaline earth metal and a carrier carrying the catalytic layer, characterized in that the carrier has a porosity of 40% or below. According to this catalyst body, the invasion of the alkali metal and/or the alkaline earth metal contained in the catalytic layer into the inside of the carrier is inhibited and thus the carrier can sustain the strength and NOx absorptivity required as a carrier over a long period of time even upon exposure to a high temperature.

Abstract: A catalyst body is obtained by loading, on a carrier, a catalyst layer containing an alkali metal and/or an alkaline earth metal, wherein at least one kind of alkali metal and/or alkaline earth metal is allowed to be present in the carrier and/or between the carrier and the catalyst layer. With this catalyst body, the deterioration of the carrier caused by the alkali metal, etc. is prevented effectively and the long-term use has been made possible.

Abstract: A honeycomb structure 1 having numerous through channels passing through along the X axis and being partitioned with porous partition walls 2 which is characterized in that: a total pore volume (D) cc/g in end portions of the partition walls 2 is smaller than the total pore volume in other portions of partition walls 2; and relationships between the total pore volume (D) cc/g in end portions and the partition wall thickness (B) ?m and cell pitch (C) mm in other portions of partition walls are defined as; the total pore volume (D)?the partition wall thickness (B)×0.004, and the total pore volume (D)?(1/the cell pitch (C))×0.18; and a method of producing a honeycomb structure. There is provided with the honeycomb structures 1 having various cell structures and being reinforced at their end portions, with exhibiting satisfactory and practical erosion resistance.

Abstract: There is provided a catalyst carrier comprising ceramic substrate composed mainly of ceramics, and a pre-coat layer applied on the ceramic substrate, wherein the pre-coat layer comprises titanium oxide (TiO2) in an amount of at least 30 mass %. Also there is provided a catalyst body comprising such a catalyst carrier, and alkali metal and/or alkaline earth metal loaded on the catalyst carrier. There are provided a catalyst carrier showing less deterioration by alkaline metal and/or alkaline earth metal to be loaded on the carrier, and a catalyst body showing less deterioration by alkaline metal and/or alkaline earth metal being loaded on the carrier.

Abstract: A carrier having a specific structure, characterized in that it has alumina and, optionally, a substance liable to react with an alkali metal and/or an alkaline earth metal both used as a catalyst component and/or an alkali metal and/or an alkaline earth metal, which are disposed in the carrier or on the cell wall surface of the carrier; a method for production of the carrier; and a catalyst body comprising the carrier and a catalytic material coated thereon. The use of the carrier allows production of a catalyst body which comprises the carrier and a catalytic material coated thereon, containing an alkali metal and/or an alkaline earth metal, such as Li, Na, K, Ca or the like and which is less susceptible to the deterioration of the carrier caused by the above metal even when used over a long period of time.

Abstract: The present invention provides a ceramic filter to be used at a high temperature, and it contains a substance having preferential reactivity with an ash component contained in materials captured by the ceramic filter and not removed by a high temperature treatment such as combustion over the principal component of the ceramic filter; the reaction between the ash component being not removed by a high temperature treatment such as combustion of the filter and remaining accumulated and the filter component to cause melting of the filter being suppressed to attain a long period of service.

Abstract: A ceramic-made filter for capturing the particulates present in the exhaust gas discharged from diesel engines, wherein a ceramic particles layer made of heat-resistant ceramic particles is formed on a filter by coating, the heat-resistant ceramic particles having a BET specific surface area of 300 m2/g or less. In this ceramic-made filter, the melting of the filter caused by the ash remaining and accumulating after the particulates captured by the filter have been burnt, can be prevented easily without using a large system or the like.

Abstract: A catalyst for purification of exhaust gas includes a carrier, and a catalyst layer containing an alkali metal and/or an alkaline earth metal as an NOx-adsorbing component, the catalyst layer being loaded on the carrier, in which catalyst the carrier-composing material contains Si in an amount of 0.5 to 10.0% by weight as expressed as an oxide. Since the inclusion of Si can suppress the deterioration of the carrier caused by the alkali metal and/or the alkaline earth metal during the use of the catalyst, the catalyst can be used over a long period.

Abstract: The invention is directed to a filter made of a porous ceramics sintered body has a honeycomb structure having a large number of through channels partitioned by partition walls and passing through along an axial direction. When a ratio of a pore volume having a diameter of 30 &mgr;m or more to a total pore volume, measured by a method of mercury penetration, of the filter is P1(%) and a thickness of said partition wall is T (&mgr;m), these satisfy the relationship defined by the following formula: P1×10≦T. In case of this filter, one may produce it relatively easily on a large scale without adjustment requiring the change of the properties of material for a filter, and the filter can flexibly cope with various uses.

Abstract: A honeycomb structural body for exhaust gas purification, characterized in that the cell partition walls (ribs) satisfy a relation shown by the following expression (1), with respect to the material properties and the structure of cell:

Abstract: A honeycomb structure having, in the axial direction, a number of through-channels separated by partition walls, which honeycomb structure contains refractory particles and a vitreous component and is porous. Although the honeycomb structure contains refractory particles such as silicon carbide particles or the like, it can be produced at a relatively low firing temperature; therefore, the honeycomb structure has a low production cost and a high yield and can be provided at a low price.

Abstract: A catalyst carrying a catalyst material containing an alkaline metal and/or an alkaline earth metal on a carrier and used as an NOx trap catalyst for purifying automobile exhaust gas and the like comprises alumina incorporated into the carrier and/or placed between the carrier and the catalyst material, thereby suppressing the deterioration of the carrier caused by the metals such as Li, Na, K and Ca to be used as an alkaline metal and/or an alkaline earth metal and enabling it to be used for a extended period of time.

Abstract: A honeycomb structure 1 having numerous through channels passing through along the X axis and being partitioned with porous partition walls 2 which is characterized in that: a total pore volume (D) cc/g in end portions of the partition walls 2 is smaller than the total pore volume in other portions of partition walls 2; and relationships between the total pore volume (D) cc/g in end portions and the partition wall thickness (B) &mgr;m and cell pitch (C) mm in other portions of partition walls are defined as; the total pore volume (D)≦the partition wall thickness (B)×0.004, and the total pore volume (D)≦(1/the cell pitch (C))×0.18; and a method of producing a honeycomb structure. There is provided with the honeycomb structures 1 having various cell structures and being reinforced at their end portions, with exhibiting satisfactory and practical erosion resistance.

Abstract: A catalyst-adsorbent for purification of exhaust gases, including a monolithic carrier and a catalyst-adsorbent layer formed thereon, the catalyst-adsorbent layer including a catalyst for reduction of the carbon monoxide, hydrocarbons and nitrogen oxides emitted from internal combustion engines and an adsorbent for reduction of the hydrocarbons emitted during cold start of the engines. The catalyst is composed mainly of catalyst particles each including a heat-resistant inorganic oxide and at least one noble metal selected from Pt, Pd and Rh, loaded thereon, the catalyst containing at least catalyst particles each comprising a heat-resistant inorganic oxide and 2-30% by weight, based on the oxide, of Pd loaded thereon, the adsorbent comprising adsorbent particles composed mainly of zeolite.