Provided is an exhaust gas purification device that ensures an improved purification performance and a suppressed pressure loss. An exhaust gas purification device of the present disclosure includes a honeycomb substrate and an inflow cell side catalyst layer. disposed on a surface on the inflow cell side in an inflow side region of the partition wall. When a gas permeability coefficient of an inflow side partition wall portion including the inflow side region of the partition wall and the inflow cell side catalyst layer is Ka and a gas permeability coefficient of an outflow side partition wall portion including an outflow side region at least from the predetermined position to an outflow side end of the partition wall is Kb, a ratio Ka/Kb of the gas permeability coefficients is within a range of 0.4 or more and 0.8 or less.

A functional structural body includes a skeletal body of a porous structure composed of a zeolite-type compound, and at least one type of metallic nanoparticles present in the skeletal body, the skeletal body having channels connecting with each other, the metallic nanoparticles being present at least in the channels of the skeletal body.

A catalyst for purification of exhaust gas including a substrate, and a catalyst coat layer which is formed on a surface of the substrate and contains catalyst particles, wherein the catalyst coat layer has an average thickness ranging 25 to 150 μm, a void fraction, as determined by scanning electron microscope observation of a cross-section of the catalyst coat layer, ranging 1.5 to 8.0% by volume, 60 to 90% by volume of all voids in the catalyst coat layer are high-aspect ratio pores which have equivalent circle diameters ranging 2 to 50 μm in a cross-sectional image of a cross-section of the catalyst coat layer perpendicular to a flow direction of exhaust gas in the substrate, and which ratios of 5 or higher, the high-aspect ratio pores have an average aspect ratio ranging 10 to 50, and a noble metal is supported on the entire catalyst coat layer.

One object is to provide a useful aldehyde decomposition catalyst, and an exhaust gas treatment apparatus and an exhaust gas treatment method using the aldehyde decomposition catalyst that achieve low cost and sufficient aldehyde decomposition performance with a small amount of the catalyst. An aldehyde decomposition catalyst of the present invention is made of a zeolite in a cation form NH.sub.4 having a structure of CHA or MOR and carrying Cu.

There is disclosed a highly crystalline, small crystal, ferrierite zeolite prepared from a gel containing a source of silica, alumina, alkali metal and a combination of two templating agents. The resulting material includes ferrierite crystals having a particle size of about or less than about 200 nm. The desired crystal size can be achieved by using a specific composition of the gel. The purity of the material and the crystal size was determined by using X-ray powder diffraction and scanning electron microscopy. The material has excellent surface area and micropore volume as determined by nitrogen adsorption.

One object is to provide an aldehyde decomposition catalyst, and an exhaust gas treatment apparatus and an exhaust gas treatment method using the aldehyde decomposition catalyst that achieve low cost and sufficient aldehyde decomposition performance with a small amount of the catalyst. An aldehyde decomposition catalyst of the present invention is made of a zeolite in a cation form NH.sub.4 having a structure selected from MFI and BEA and carrying at least one metal selected from the group consisting of Cu, Mn, Ce, Zn, Fe, and Zr.

A composition for exhaust gas purification including first alumina including alumina containing lanthanum and second alumina including alumina containing lanthanum. The first alumina has a higher lanthanum content than the second alumina. The second alumina has a larger particle size than the first alumina. The lanthanum content of the first alumina is preferably 2 to 12 mass %, in terms of oxide, based on the total mass of alumina and lanthanum oxide of the first alumina. The lanthanum content of the second alumina is preferably 9 mass % or less, in terms of oxide, based on the total mass of alumina and lanthanum oxide of the second alumina.

A noble metal-free lanthanum transition metal perovskite catalyst material. The noble metal-free lanthanum transition metal perovskite catalyst material may include a two phase mixture of a lanthanum transition metal perovskite with an alkali or alkaline earth metal carbonate, a lanthanum transition metal perovskite doped with an alkali or alkaline earth metal, or a combination thereof. The lanthanum transition metal perovskite catalyst material provides direct decomposition of NOx into N.sub.2 and O.sub.2 without the presence of a noble metal and in the presence of excess O.sub.2.

Described are catalyst materials and catalytic articles comprising a metal exchanged SAPO material comprising a plurality of substitutional sites consisting essentially of Si(4Al) sites and substantially free of Si(0Al) sites. The materials and catalytic articles are useful in methods and systems to catalyze the reduction of nitrogen oxides in the presence of a reductant.

The oxide-containing particles (transition metal oxide-containing cerium dioxide particle) exert a catalyst performance, and include at least an iron oxide containing an iron component and a manganese oxide containing a manganese component on a surface of each of cerium dioxide particles, wherein the iron oxide and manganese oxide have smaller particle diameters than that of the cerium dioxide particles, and the content rate of the iron oxide and the manganese oxide is within the range of from 15.0% by mass to 35.0% by mass.