An object of the present invention is to provide a composition for forming an undercoat layer capable of forming an undercoat layer that does not easily peel off from the substrate, an undercoat layer formed by the composition, as well as an exhaust gas purification catalyst and an exhaust gas purification apparatus each including the undercoat layer, and, to achieve the object, the present invention provides a composition for forming an undercoat layer, the composition containing tin oxide microparticles and tin oxide nanoparticles, wherein a content of the tin oxide nanoparticles is 8% by mass or more and 30% by mass or less, with respect to a total content of the tin oxide microparticles and the tin oxide nanoparticles, an undercoat layer formed by the composition, as well as an exhaust gas purification catalyst and an exhaust gas purification apparatus each including the undercoat layer.

The structured catalyst for oxidation for exhaust gas purification includes a support having a porous structure constituted by a zeolite-type compound, and at least one type of oxidation catalyst that is present in the support and selected from the group consisting of metal and metal oxide, the support having channels that communicate with each other, and the oxidation catalyst being present in at least the channels of the support.

A composite, zone-coated, dual-use ammonia (AMOX) and nitric oxide oxidation catalyst (12) comprises: a substrate (5) having a total length L and a longitudinal axis and having a substrate surface extending axially between a first substrate end (I) and a second substrate end (O); two or more catalyst washcoat zones (1; 2) comprised of a first catalyst washcoat layer (9) comprising a refractory metal oxide support material and one or more platinum group metal components supported thereon and a second catalyst washcoat layer (11) different from the first catalyst washcoat layer (9) and comprising a refractory metal oxide support material and one or more platinum group metal components supported thereon, which two or more catalyst washcoat zones (1; 2) being arranged axially in series on and along the substrate surface, wherein a first catalyst washcoat zone (1) having a length L.sub.1, wherein L.sub.1<L, is defined at one end by the first substrate end (I) and at a second end (13) by a first end (15) of a second catalyst washcoat zone (2) having a length L.sub.2, wherein L.sub.2<L, wherein the first catalyst washcoat zone (1) comprises a first refractory metal oxide support material and one or more platinum group metal components supported thereon; and the second catalyst washcoat zone comprises a second refractory metal oxide support material and one or more platinum group metal components supported thereon; and a washcoat overlayer (G) extending axially from the first substrate end for up to 200% of the axial length of the underlying first catalyst washcoat layer, which washcoat overlayer comprising a particulate metal oxide loading of >48.8 g/l (>0.8 g/in.sup.3), wherein the particulate metal oxide is an aluminosilicate zeolite including at least one of copper, iron and manganese, wherein a total platinum group metal loading in the first catalyst washcoat zone (1) defined in grams of platinum group metal per litre of substrate volume (g/l) is different from the total platinum group metal loading in the second catalyst washcoat zone (2).

A device for treating exhaust gases of an internal combustion engine includes: a heating disk arranged in a housing; and a main catalytic converter arranged downstream of the heating disk in the flow direction in the housing. The flow can pass through the heating disk and the main catalytic converter in the flow direction along a plurality of flow channels. The heating disk is formed from a metallic honeycomb body and the main catalytic converter is formed from a ceramic honeycomb body fixed in relation to the housing by a fixing structure. The heating disk is electrically contacted by an electrical feedthrough guided through the housing from the outside to the inside.

An exhaust gas purification catalyst apparatus has a honeycomb base material and a catalyst noble metal supported by the honeycomb base material, wherein: the honeycomb base material contains ceria-zirconia composite oxide particles as one of the constituent materials, is of a wall flow type, and includes inlet-side cells and outlet-side cells demarcated by porous partition walls; the catalyst noble metal is supported in inlet-side support regions and outlet-side support regions; each of the inlet-side support regions is formed with a specific length from the exhaust gas flow upstream end; the catalyst noble metal 70% support depth is not greater than 50% of the thickness of the porous partition walls; each of the outlet-side support regions is formed with a specific length from the exhaust gas flow downstream end; and the catalyst noble metal 70% support depth is greater than 50% of the thickness of the porous partition walls.

An electrically heating converter includes: a pillar shaped honeycomb structure made of conductive ceramics, including: an outer peripheral wall; and a partition wall disposed on an inner side of the outer peripheral wall, the partition wall defining a plurality of cells, each of the cells penetrating from one end face to other end face to form a flow path; metal electrodes; a pressing member configured to press each of the metal electrodes against the pillar shaped honeycomb structure, so that the pillar shaped honeycomb structure is electrically connected to each of the metal electrodes; and an antioxidant material of (i) or (ii) below: (i) an antioxidant material provided between the pillar shaped honeycomb structure and each of the metal electrodes, or (ii) an antioxidant material provided from a surface of the pillar shaped honeycomb structure over an outer surface of each of the metal electrodes.

A honeycomb structure made of ceramics, wherein the honeycomb structure includes: a borosilicate; and silicon particles doped with at least one dopant, the dopant is a Group 13 element or a Group 15 element, the silicon particles have a dopant amount (A) of 1×10.sup.16 to 5×10.sup.20/cm.sup.3, and the honeycomb structure has a silicon particle content (B) of 30 to 80% by mass.

A pillar shaped honeycomb structure for induction heating, the honeycomb structure being made of ceramics and including: an outer peripheral wall; and a partition wall disposed on an inner side of the outer peripheral wall, the partition wall defining a plurality of cells, each of the cells penetrating from one end face to other end face to form a flow path, wherein a composite material containing a conductor and a non-conductor is provided in the cells in a region of 50% or less of the total length of the honeycomb structure from one end face, and wherein the conductor is a conductor that generates heat in response to a change in a magnetic field.

A honeycomb extrusion die body (401) including inlet (414) and exit (402) faces, and a plurality of pins (406) on the exit face (402) defining a matrix of intersecting wide slots (425) and narrow slots (427). The wide slots (425) have an exit width (W1) greater than an exit width (W2) of the narrow slots (427). The die body (401) further includes feedholes (422) at the inlet face (414) and intersecting with inlet portions (416) to the wide slots (425) and/or the narrow slots (427). Some of the pins (406) defining the wide slots (425) include a first surface indentation feature (430) that is (i) located between the inlet portion (416) and the wide slot exit and (ii) spaced away from the wide slot exit. Some of the pins (406) defining the narrow slots (427) include a second surface indentation feature (434) that is (i) located between the inlet portion and the narrow slot exit and (ii) spaced away from the narrow slot exit.

The invention concerns a method for unblocking pores in a metal zeolite based selective catalytic reduction (SCR) catalyst. The method includes filling, at least partially, the SCR catalyst with a liquid, the liquid being preferably distilled water. The method includes letting said liquid inside the SCR catalyst enough time to allow said liquid to dissolve, at least partially, the obstructions and to penetrate into the pores. The method includes heating the SCR catalyst at a temperature above the ebullition temperature of the liquid so as to vaporize the part of the liquid remained into the pores, and generate steam flows through the obstructions, the steam flows removing the obstructions and unblocking the pores, wherein no hydrocarbons are injected during the step of heating.