Abstract: A ceramic carrier comprising a substrate ceramic containing Mg, Al, Si and O as constituent elements and containing, as the second component, an element other than said constituent elements. The support contains many microvoids capable of absorbing thermal expansion, the porosity is larger than 28%, and the thermal expansion coefficient is smaller than 2.3×10−6/° C. The second component enables the direct loading of a catalytic component.

Abstract: The object of the present invention is to provide a ceramic body that can support a required amount of a catalyst component, without lowering the characteristics such as strength, being manufactured without forming a coating layer and providing a high performance ceramic catalyst that is excellent in practical utility and durability. A noble metal catalyst is supported directly on the surface of the ceramic body and the second component, consisting of compound or composite compound of element having d or f orbit in the electron orbits thereof such as W, Co, Ti, Fe, Ga and Nb, is dispersed in the first component made of cordierite or the like that constitutes the substrate ceramic. The noble metal catalyst can be directly supported by bonding strength generated by sharing the d or f orbits of the second component, or through interaction with the dangling bond that is generated in the interface between the first component and the second component.

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

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: 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: In a catalyst body using a direct support, this invention provides a ceramic catalyst body capable of preventing degradation resulting from aggregation of catalyst components, excellent in low thermal capacity and low pressure loss and having excellent catalytic performance and high durability. Catalyst particles prepared by supporting a catalyst metal such as Pt on intermediate substrate particles and an assistant catalyst of a metal oxide such as CeO2 are directly supported on a ceramic support using cordierite, a part of constituent elements of which is replaced, as a substrate and capable of directly supporting the catalyst components on replacing elements so introduced. Even when the CeO2 particles having low bonding strength move, the catalyst metal such as Pt is prevented from moving and aggregating because it is bonded to the intermediate substrate particles, and catalyst performance can be maintained for a long time.

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: It is an object of the present invention to realize an oxidizing catalyst having weak oxidizing capability such that NO is oxidized to NO2 and HC is not oxidized, and high thermal durability, and to use it as a catalyst in a preceding stage for supplying NO2 and HC stably to a catalyst in the following stage.

Abstract: This invention aims at achieving early activation by use of a catalytic body having a low thermal capacity, and a low pressure loss, without using a coating layer to reduce exhaust emission. The invention is directed also to improve exhaust purification performance by improving the combination of catalytic bodies and performance of each catalytic body. In the invention, a start catalyst 1 is arranged at an upstream portion of an exhaust pipe P of a car engine E and a three way catalyst 2 is disposed on the downstream side. The start catalyst 1 can directly support catalytic components through chemical bonds by incorporating replacing elements into a substrate ceramic having high heat resistance such as cordierite. Because a coating layer is not necessary, the catalyst of the invention has a low heat capacity and a large open area and achieves reduction of exhaust emission, and reduction of a pressure loss, through early activation.

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.

Abstract: The present invention improves a ceramic carrier capable of directly supporting a catalyst component and provides a ceramic carrier and a ceramic catalyst body which have high catalyst performance and practical value.

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.

Abstract: The object of the present invention is to improve the catalyst performance of a ceramic support that enables a catalyst component to be loaded directly, prevent thermal degradation and so forth, and enhance durability.

Abstract: There is provided a process for obtaining a cordierite honeycomb structural body with thin cell walls and no molding defects such as cell breakage or the like. Cell breakage is prevented by limiting the maximum particle size of the cordierite starting material powder to no greater than 85% of the slit width of the extrusion molding die so that the starting material particles will not clog inside the slits or the introduction port of the slits. As one cordierite starting material, talc with a mean particle size of 5 &mgr;m or greater is used to give a honeycomb structural body with a void volume of greater than 30%, for production of a honeycomb structural body, with good moldability, having a small thickness and a low heat capacity. It is preferred to add to the starting material at least a lubricant/humectant, a binder and/or a mixture of a water-soluble polyhydric alcohol derivative and a polyhydric alcohol.

Abstract: A reinforcing layer 4 of nearly a cylindrical shape is formed along the outer circumferential portion of a ceramic honeycomb structure which comprises a cylindrical outer circumferential skin layer 1 and cell walls 2, the reinforcing layer 4 being formed at a position maintaining a one-cell pitch from the outer circumferential skin layer 1 and extending from one end surface of the ceramic honeycomb structure toward the other end surface thereof. The reinforcing layer 4 is integrally formed, of the same material, with the outer circumferential skin layer 1 and the cell walls 2 to reinforce the strength in the circumferential direction. This makes it possible to decrease the thickness of the cell walls 2 to not larger than 100 &mgr;m yet maintaining moldability and resistance to thermal shock.

Abstract: A cordierite honeycomb body is produced by forming a cordierite material including kaoline into a honeycomb shape and sintering it. The kaoline included in the cordierite material is at least partly composed of kaolinite having a Hinckley crystallinity index of 0.5 or more thereby having a less amorphous phase portion in a kaolinite particle. Therefore, when the cordierite material is sintered, the number of micropores generated in the cordierite is decreased due to the less amorphous phase portion in the kaolinite particles. As a result, density of the cordierite is increased without increasing a C.T.E. thereof. Thus, the cordierite honeycomb body has sufficient strength even when thickness of a cell wall thereof is decreased.

Abstract: There are provided thin-walled honeycomb structural bodies with high strength and excellent thermal shock resistance by using as the starting material for cordierite honeycomb structural bodies a combination of talc with a median particle diameter exceeding 7 .mu.m and not greater than 20 .mu.m and with a CaO content of 0.2 wt % or less and another cordierite material such as kaolin with a median particle diameter of not greater than 1 .mu.m, molding the starting material into a honeycomb shape with a cell wall thickness of 130 .mu.m or less, and firing the mold.