A honeycomb structure including: a pillar-shaped honeycomb structure portion having an outer peripheral wall and partition walls disposed on an inner side of the outer peripheral wall and defining a plurality of cells extending from one end face to another end face to form flow paths; and at least an electrode portion disposed on an outer surface of the outer peripheral wall of the pillar-shaped honeycomb structure portion, wherein the pillar-shaped honeycomb structure portion is formed of ceramics containing either or both of Si and SiC, the electrode portion contains either or both of a metal and a metal compound in addition to an oxide, and a volume ratio of the oxide on an inner peripheral side of the electrode portion is higher than a volume ratio of the oxide on an outer peripheral side of the electrode portion.

An exhaust gas treatment system (1) comprises a catalyst article (5) for the treatment of an exhaust gas, the catalyst article (5) comprising a non-metallic substrate (20) comprising a plurality of catalytically-active transition-metal-doped iron oxide magnetic particles (45), and an inductive heater (70) for inductively heating the plurality of catalytically-active magnetic particles by applying an alternating magnetic field.

A ceramic porous body including: skeleton portions including an aggregate and at least one bonding material; and pore portions formed between the skeleton portions, the pore portions being capable of allowing a fluid to flow therethrough, wherein the pore portions have a pore volume ratio of pores having a pore diameter of from 10 to 15 m, of from 4 to 17% or more.

A ceramic porous body including: skeleton portions including an aggregate and at least one bonding material; and pore portions formed between the skeleton portions, the pore portions being capable of allowing a fluid to flow therethrough, wherein the pore portions have a pore volume ratio of pores having a pore diameter of from 10 to 15 m, of from 4 to 17% or more.

A long-life catalyst which can be easily and inexpensively manufactured and has high activity and suppressed leakage of metal. A catalyst according to some embodiments includes: a substrate; and a first metal atom as a catalytic center. The substrate contains a non-metallic atom and a second metal atom, and the non-metallic atom is any one selected from the group consisting of a group 15 element, a group 16 element and a group 17 element.

A long-life catalyst which can be easily and inexpensively manufactured and has high activity and suppressed leakage of metal. A catalyst according to some embodiments includes: a substrate; and a first metal atom as a catalytic center. The substrate contains a non-metallic atom and a second metal atom, and the non-metallic atom is any one selected from the group consisting of a group 15 element, a group 16 element and a group 17 element.

A coating material for a honeycomb structure, the coating material containing: from 1% by mass to 10% by mass of first ceramic fibers having an average axial length of from 80 m to 200 m in an inorganic raw material; and from 0.1% by mass to 15% by mass of second ceramic fibers having an average axial length of from 50 m to 70 m in the inorganic raw material.

A coating material for a honeycomb structure, the coating material containing: from 1% by mass to 10% by mass of first ceramic fibers having an average axial length of from 80 m to 200 m in an inorganic raw material; and from 0.1% by mass to 15% by mass of second ceramic fibers having an average axial length of from 50 m to 70 m in the inorganic raw material.

Provided is an electrically heated catalytic converter including at least a conductive substrate and an electrode member that is fixed to the substrate, in which a protective film is formed on a surface of at least a portion of the electrode member. In the electrically heated catalytic converter, at least a portion of the protective film is formed of Al.sub.2O.sub.3, SiO.sub.2, a composite material of Al.sub.2O.sub.3 and SiO.sub.2, or a composite oxide including Al.sub.2O.sub.3, SiO.sub.2, or a composite material of Al.sub.2O.sub.3 and SiO.sub.2 as a major component, the protective film has an amorphous structure or a partially crystalline glass structure having a crystallization rate of 30 vol % or lower with respect to the entire portion of the protective film, and a thickness of the protective film is in a range of 100 nm to 2 m.

Provided is an electrically heated catalytic converter including at least a conductive substrate and an electrode member that is fixed to the substrate, in which a protective film is formed on a surface of at least a portion of the electrode member. In the electrically heated catalytic converter, at least a portion of the protective film is formed of Al.sub.2O.sub.3, SiO.sub.2, a composite material of Al.sub.2O.sub.3 and SiO.sub.2, or a composite oxide including Al.sub.2O.sub.3, SiO.sub.2, or a composite material of Al.sub.2O.sub.3 and SiO.sub.2 as a major component, the protective film has an amorphous structure or a partially crystalline glass structure having a crystallization rate of 30 vol % or lower with respect to the entire portion of the protective film, and a thickness of the protective film is in a range of 100 nm to 2 m.