A honeycomb filter body comprises: a clean filter pressure drop of (P.sub.1) and a clean filtration efficiency of (FE.sub.1); a porous ceramic honeycomb body comprising a first end, a second end, and a plurality of walls having wall surfaces defining a plurality of inner channels, the porous ceramic honeycomb body comprising a base clean filter pressure drop (P.sub.0) and a base clean filtration efficiency (FE.sub.0); and a porous inorganic layer disposed on one or more of the wall surfaces of the porous ceramic honeycomb body.

A honeycomb filter body comprises: a clean filter pressure drop of (P.sub.1) and a clean filtration efficiency of (FE.sub.1); a porous ceramic honeycomb body comprising a first end, a second end, and a plurality of walls having wall surfaces defining a plurality of inner channels, the porous ceramic honeycomb body comprising a base clean filter pressure drop (P.sub.0) and a base clean filtration efficiency (FE.sub.0); and a porous inorganic layer disposed on one or more of the wall surfaces of the porous ceramic honeycomb body.

Methods of producing a ceramic article include heating the ceramic green body containing a quantity of one or more organic materials to extract only a fraction of the organic materials from the ceramic green body by exposing the ceramic green body to a process atmosphere which is heated to a hold temperature of from 225° C. to about 400° C. and has from 2% to 7% O.sub.2 by volume of the process atmosphere. The method further includes cooling the ceramic green body to a temperature of below 200° C., exposing the ceramic green body to a higher concentration of O.sub.2 than in the process atmosphere of the heating step, and firing the ceramic green body to form the ceramic article. Volatile extraction units for implementing the methods are also described.

A cement composition for application to a ceramic substrate, such as a cement skin composition for application to a ceramic honeycomb body is provided. The cement composition includes a first source of inorganic particles having a mean particle diameter <50 nm, wherein the first source of inorganic particles is present at about <15% (by dry weight), a second source of inorganic particles having a mean particle diameter of from about 50 nm to about 700 nm, wherein the second source of inorganic particles is present at from about 5% to about 15% (by dry weight), and a water-soluble organic binder. An inorganic fibrous material can be present at about <15% (based on dry weight). The amount of at least one of the first source of inorganic particles or the inorganic fibrous material is greater than 0% (by dry weight).

A cement composition for application to a ceramic substrate, such as a cement skin composition for application to a ceramic honeycomb body is provided. The cement composition includes a first source of inorganic particles having a mean particle diameter <50 nm, wherein the first source of inorganic particles is present at about <15% (by dry weight), a second source of inorganic particles having a mean particle diameter of from about 50 nm to about 700 nm, wherein the second source of inorganic particles is present at from about 5% to about 15% (by dry weight), and a water-soluble organic binder. An inorganic fibrous material can be present at about <15% (based on dry weight). The amount of at least one of the first source of inorganic particles or the inorganic fibrous material is greater than 0% (by dry weight).

A cement mixture for application to a honeycomb body and a method of forming a plugged ceramic honeycomb body is provided. The cement mixture contains a plurality of inorganic particles including at least about 50% of a refractory material selected from at least one of alumina and zirconia and less than about 15% titania (by weight), a pore forming agent, an organic binder, and a liquid vehicle.

A cement mixture for application to a honeycomb body and a method of forming a plugged ceramic honeycomb body is provided. The cement mixture contains a plurality of inorganic particles including at least about 50% of a refractory material selected from at least one of alumina and zirconia and less than about 15% titania (by weight), a pore forming agent, an organic binder, and a liquid vehicle.

An exhaust treatment apparatus for treating exhaust gas flowing through an exhaust line housing from an upstream location to a downstream location in a downstream direction, the exhaust treatment apparatus comprising a ceramic filter body having a honeycomb structure of a plurality of intersecting porous ceramic walls extending from a first end to a second end in an axial direction and defining a plurality of channels extending in the axial direction, wherein a first transverse face at the first end comprises metal oxide particles affixed to a portion of the intersecting walls. The metal oxide particles may be affixed to the upstream end, or the downstream end, or both the upstream and downstream ends. Preferably the metal oxide particles provide reinforcement to the underlying portion of the walls, and of the honeycomb structure itself.

An exhaust treatment apparatus for treating exhaust gas flowing through an exhaust line housing from an upstream location to a downstream location in a downstream direction, the exhaust treatment apparatus comprising a ceramic filter body having a honeycomb structure of a plurality of intersecting porous ceramic walls extending from a first end to a second end in an axial direction and defining a plurality of channels extending in the axial direction, wherein a first transverse face at the first end comprises metal oxide particles affixed to a portion of the intersecting walls. The metal oxide particles may be affixed to the upstream end, or the downstream end, or both the upstream and downstream ends. Preferably the metal oxide particles provide reinforcement to the underlying portion of the walls, and of the honeycomb structure itself.

A method of making a titanium dioxide nanowire array includes contacting a substrate with a solvent comprising a titanium (III) precursor, an acid, and an oxidant while microwave heating the solvent, thereby forming a hydrogen titanate H2Ti2O5.H2O nanowire array. The hydrogen titanate nanowire array is annealed to form a titanium dioxide nanowire array. The substrate is seeded with titanium dioxide before starting the hydrothermal synthesis of the hydrogen titanate nanowire array. The titanium dioxide nanowire array is loaded with a platinum group metal to form an exhaust gas catalyst. The titanium dioxide nanowire array can be used to catalyze oxidation of combustion exhaust.