The invention relates to a method for producing iron-containing shaped catalyst bodies by means of 3D printing technology and to iron-containing shaped catalyst bodies that are obtainable by this method and to their use as catalysts in the ammonia synthesis or the Fischer-Tropsch reaction.

A honeycomb filter includes a pillar-shaped honeycomb structure having porous partition walls provided, surrounding a plurality of cells which serve as fluid through channels extending from an inflow end face to an outflow end face, and a porous plugging portion provided either at an end on the inflow end face or the outflow end face of the cells, wherein the plugging portion is composed of a porous material, the honeycomb structure has a central region and a circumferential region, and a ratio of an area of the circumferential region with respect to that of the central region ranges from 0.1 to 0.5, porosity of a central plugging portion in the central region is lower than that of a circumferential plugging portion in the circumferential region, and the porosity of the central plugging portions ranges from 60% to 68%, and that of the circumferential plugging portions ranges from 70% to 85%.

A catalyst fibrous structure having a catalyst metal carried on a fibrous structure, wherein (a) a Log differential micropore volume distribution curve thereof obtained by measurement using a mercury intrusion technique has a peak having a maximum micropore diameter in the range of from 0.1 μm to 100 μm; (b) a Log differential micropore volume at the peak is 0.5 mL/g or more; and (c) an amount of a catalyst metal compound and a binder carried per unit volume is 0.05 g/mL or more. A production method for producing a catalyst fibrous structure having: (1) mixing a catalyst metal compound or a catalyst precursor, and an inorganic binder and a solvent; (2) grinding the mixture to obtain a coating material of the catalyst metal compound or the catalyst precursor having a median particle diameter of 2 μm or less and a viscosity of from 10 mPa.Math.s to 200 mPa.Math.s; (3) impregnating a fibrous structure with the coating material to fill up voids of the fibrous structure with the coating material of the catalyst metal compound or the catalyst precursor; (4) heating and drying the fibrous structure, directly as it is, at a temperature not lower than the boiling point of the solvent; and (5) heating and calcination the dried fibrous structure at a temperature not lower than the dehydration temperature of the inorganic binder to obtain a catalyst fibrous structure.

Porous silica-carbon composites are obtained by mixing fine particulate carbon dispersed in water by a surfactant, alkali metal silicate aqueous solution, and mineral acid so as to produce co-dispersion in which silica hydrosol, produced by reaction of the alkali metal silicate and the mineral acid, and the fine particulate carbon are uniformly dispersed, and gelling silica hydrosol, contained in the co-dispersion, and making the co-dispersion into porous bodies. The porous silica-carbon composites are prepared so as to have specific surface area from 20 to 1000 m.sup.2/g, pore volume from 0.3 to 2.0 ml/g, and average pore diameter from 2 to 100 nm.

Provided is a honeycomb catalyst in which a plurality of through holes are provided in proximity to each other in a row arrangement in the lengthwise direction, and are set apart by partitions. A honeycomb unit contains at least two types of inorganic particles and an inorganic binder. The inorganic particles contain zeolite having an SiO2/Al2O3 composition ratio of less than 15 and a CHA structure and an oxide other than zeolite, which has a positive thermal expansion coefficient. The ratio (X:Y) of the volume (X) of zeolite and the volume (Y) of oxide is 50:50 to 80:20. A displacement amount of absorbed water is reduced and cracking is controlled while maintaining high NOx purging performance.

A ceramic honeycomb structure having pluralities of flow paths partitioned by porous cell walls; (a) the cell walls having porosity of 50-60%; and (b) in a pore diameter distribution in the cell walls measured by mercury porosimetry, (i) pore diameters at cumulative pore volumes corresponding to particular percentages of the total pore volume being within specific ranges and having specific relationships; and (ii) the difference between a logarithm of the pore diameter at a cumulative pore volume corresponding to 20% of the total pore volume and a logarithm of the pore diameter at 80% being 0.39 or less, and its production method.

Provided are a composite material that has lower volume resistivity in comparison with SiC, SiC—Si, and the like, which are materials for forming constituent elements of an EHC, has low temperature dependence of volume resistivity, and thus is able to form a constituent element of a high-performance EHC; an electrode film, an electrode terminal, and a honeycomb substrate that are constituent elements of an EHC formed with such composite material, and a method for producing them. The composite material contains MoSi.sub.2 and at least one of Si or SiC, and is a material for forming a constituent element of an electrically heated catalytic converter. An electrode film 2, an electrode terminal 3, and a substrate 1 are produced from such composite material.

Shaped porous carbon products and processes for preparing these products are provided. The shaped porous carbon products can be used, for example, as catalyst supports and adsorbents. Catalyst compositions including these shaped porous carbon products, processes of preparing the catalyst compositions, and various processes of using the shaped porous carbon products and catalyst compositions are also provided.

A catalyst converter includes: a substrate (1) having a cell structure formed of a center area (1A) having the highest cell density, a peripheral area (1C) having the lowest cell density, and an intermediate area (1B) having the cell density between that of the center area and that of the peripheral area; a first catalyst layer formed in the center area (1A); a second catalyst layer formed in the intermediate area (1B); and a third catalyst layer formed in the peripheral area (1C). A length in a longitudinal direction of the second catalyst layer is longer than that of the first catalyst layer. A length in the longitudinal direction of the third catalyst layer is longer than that of the second catalyst layer. A ratio of the length in the longitudinal direction of the first catalyst layer to the length of the substrate is 65% or more.

Methods use a catalytic composition built up from a ceramic material including a catalytic material and a first inorganic binder and a second inorganic binder and a catalytic structure made thereof. Preferably, the structure is made by a colloidal ceramic shaping technique. The structure is used for catalytic or ion exchange applications. The catalytic structures have excellent mechanical, physicochemical and catalytic properties.