Disclosed herein are filtration articles comprising a porous ceramic structure comprising a plurality of channels separated by a plurality of porous interior walls, and a nanomembrane disposed on at least a portion of a surface of the porous ceramic structure, wherein the nanomembrane comprises nanoparticles of at least one inorganic oxide, and wherein the nanoparticles are present in a concentration ranging from about 0.001 g/L to about 1 g/L based on the total volume of the porous ceramic structure. Methods for making such filtration articles and methods for filtering a particulate from a fluid using such filtration articles are also disclosed herein.

A coated ceramic honeycomb body comprising a honeycomb structure comprising a matrix of intersecting porous walls forming a plurality of axially-extending channels, at least some of the plurality of axially-extending channels being plugged to form inlet channels and outlet channels, wherein a total surface area of the outlet channels is greater than a total surface area of the inlet channels, and wherein a catalyst is preferentially located within the outlet channels, and preferentially disposed on non-filtration walls of the outlet channels. Methods and apparatus configured to preferentially apply a catalyst-containing slurry to the outlet channels and non-filtration walls are provided, as are other aspects.

A method of manufacturing a ceramic honeycomb structure by mixing a ceramic precursor batch composition having a median particle diameter less than or equal to about 10 μm and at least one starch-based pore former having a median particle diameter greater than or equal to about 10 μm. The method also includes forming a mixture of ceramic precursor batch composition and a starch-based pore former into a green ceramic structure having a web structure, and firing the green ceramic structure to yield a ceramic honeycomb structure.

A coated ceramic honeycomb body comprising a honeycomb structure comprising a matrix of intersecting porous walls forming a plurality of axially-extending channels, at least some of the plurality of axially-extending channels being plugged to form inlet channels and outlet channels, wherein a total surface area of the outlet channels is greater than a total surface area of the inlet channels, and wherein a catalyst is preferentially located within the outlet channels. and preferentially disposed on non-filtration walls of the outlet channels. Methods and apparatus configured to preferentially apply a catalyst-containing slurry to the outlet channels and non-filtration walls are provided, as are other aspects.

A honeycomb body (300) including a plurality of radially-extending walls (322) intersecting with a plurality of circumferentially-extending walls (324), the plurality of radially-extending walls (322) and the plurality of circumferentially-extending walls (324) form a plurality of circumferential zones (334A, 334B, 334C) of cells (308). The plurality of circumferential zones (334A, 334B, 334C) of cells (308) includes a first zone of cells (334A) including two or more first rings of cells (330) and having a first cell density, and a second zone of cells (334B) including two or more rings of cells (330) having varying cell densities across the two or more rings of cells. Other structures and extrusion dies are disclosed.

A honeycomb filter includes a pillar-shaped honeycomb structure body having a porous partition wall disposed to surround a plurality of cells and a plugging portion, wherein the partition wall defining inflow cells includes partition wall parts making up sides of polygon that is sectional shape of each cell, the partition wall parts each having a surface that is a face defining the inflow cell, the partition wall part is either a first partition wall part loaded with the exhaust-gas purifying catalyst on the surface so that a percentage of the area loaded therewith exceeds 10%, or a second partition wall part loaded with the exhaust-gas purifying catalyst so that a percentage of the area loaded therewith is 10% or less, and the partition wall is configured to include one or more the first partition wall parts and one or more the second partition wall parts as the partition wall parts.

A particulate filter disclosed herein includes a wall-flow structure substrate 10 and a wash coat layer 20 held inside a partition 16 of the substrate 10. The wash coat layer 20 includes an inlet layer 22 formed to have predetermined length L.sub.A and thickness T.sub.A from near an end thereof on an exhaust gas inflow side X1, and an outlet layer 24 formed to have predetermined length L.sub.B and thickness T.sub.B from near an end thereof on an exhaust gas outflow side X2. The inlet layer 22 and the outlet layer 24 partially overlap each other. In the particulate filter disclosed herein, the inlet layer 22 contains a precious metal catalyst, while the outlet layer 24 contains substantially no precious metal catalyst. The length L.sub.A of the inlet layer is 50% or more and 75% or less of a total length L of the partition 16. Thus, the particulate filter is capable of achieving both PM collection performance and pressure-drop reduction performance at high levels.

A method is disclosed for making a catalyzed particulate filter with high clean filtration efficiency which may include applying a catalyst material to a filter body having porous filter walls, wherein filtration material comprising filtration particles are disposed on or in or both on and in porous filter walls, and the filtration material is hydrophobic while the catalyst material is applied. A catalyzed particulate filter with high clean filtration efficiency is also disclosed wherein the filter includes porous filter walls with filtration particles disposed on or in or both on and in the porous filter walls, and catalyst material disposed on or in or both on and in the porous filter walls, and wherein the catalyst material substantially does not touch the filtration particles.

A honeycomb filter comprising a pillar-shaped honeycomb structure body having a porous partition wall and a plugging portion, wherein a thickness of the partition wall is 0.257 mm or less, a porosity of the partition wall is 52 to 57%, an average pore diameter of the partition wall is 6 to 13 .Math.m, a number per unit area of pores which exist at a surface of the partition wall and which have equivalent circle opening diameters exceeding 3 .Math.m is 800 to 1500 /mm.sup.2, an average equivalent circle opening diameter of pores which exist at a surface of the partition wall and which have equivalent circle opening diameters exceeding 3 .Math.m is 8.0 to 12.0 .Math.m, and in a pore diameter distribution of the partition wall, D10 is 2.0 to 5.5 .Math.m, D90 is 13.0 to 25.5 .Math.m, and (Log(D90)-Log(D10))/Log(D50) is 0.84 or less.

A honeycomb filter comprising a pillar-shaped honeycomb structure body having a porous partition wall and a plugging portion, wherein, in a pore diameter distribution of the partition wall, in the case where the pore diameter (.Math.m) whose cumulative pore volume is 10% of the total pore volume is denoted by D10, the pore diameter (.Math.m) whose cumulative pore volume is 50% of the total pore volume is denoted by D50, and the pore diameter (.Math.m) whose cumulative pore volume is 90% of the total pore volume is denoted by D90, all of the following equations (1) to (6) are satisfied.

[00001]$\begin{array}{cc}3.9\mu \text{}\text{m<D10}& \text{­­­(1)}\end{array}$

[00002]$\begin{array}{cc}10.5\mu \text{}\text{m<D50<16}\text{.6}\mu \text{}\text{m}& \text{­­­(2)}\end{array}$

[00003]$\begin{array}{cc}\text{D90<38}\text{.7}\mu \text{}\text{m}& \text{­­­(3)}\end{array}$

[00004]$\begin{array}{cc}\left(\log \text{}\text{D90-logD10}\right)/\log \text{}\text{D50<0}\text{.80}& \text{­­­(4)}\end{array}$

[00005]$\begin{array}{cc}\log \text{}\text{D90}/\text{logD50<1}\text{.36}& \text{­­­(5)}\end{array}$

[00006]$\begin{array}{cc}\log \text{}\text{D50}/\text{logD10<1}\text{.56}& \text{­­­(6)}\end{array}$