An exhaust-gas purification catalyst that contains a perovskite-type composite oxide composed of at least Ba, Zr, Y, and Pd.

An exhaust gas-purifying catalyst includes a support and a catalytic metal as one or more precious metals supported by the support. The support includes a composite oxide having a composition represented by a general formula AB.sub.C.sub.O.sub.3, wherein A represents one or more elements selected from the group consisting of lanthanum, neodymium, and yttrium, B represents iron or a combination of iron and aluminum, C represents one or more elements selected from the group consisting of iridium, ruthenium, tantalum, niobium, molybdenum, and tungsten, and each represents a numerical value within a range of more than 0 and less than 1, and and satisfy relational formulae of > and +1.

A preparation method of perovskite catalyst, represented by the following Chemical Formula 1: La.sub.xAg.sub.(1-x)MnO.sub.3 (0.1x0.9), includes the steps of 1) preparing a metal precursor solution including a lanthanum metal precursor, a manganese metal precursor and a silver metal precursor, 2) adding maleic or citric acid to the metal precursor solution, 3) drying the mixture separately several times with sequentially elevating the temperature in the range of 160 to 210 C., and 4) calcining the dried mixture at 600 to 900 C. for 3 hours to 7 hours.

An exhaust gas-purifying catalyst includes a support and a catalytic metal as one or more precious metals supported by the support. The support includes a composite oxide having a composition represented by a general formula AB.sub.C.sub.O.sub.3, wherein A represents one or more elements selected from the group consisting of lanthanum, neodymium, and yttrium, B represents iron or a combination of iron and aluminum, C represents one or more elements selected from the group consisting of iridium, ruthenium, tantalum, niobium, molybdenum, and tungsten, and each represents a numerical value within a range of more than 0 and less than 1, and and satisfy relational formulae of > and +1.

An ammonia slip control catalyst having a layer containing perovskite and a separate layer containing an SCR catalyst is described. The ammonia slip catalyst can have two stacked layers, with the top overlayer containing an SCR catalyst, and the bottom layer containing a perovskite. The ammonia slip catalyst can alternatively be arranged in sequential layers, with the SCR catalyst being upstream in the flow of exhaust gas relative to the perovskite. A system comprising the ammonia slip catalyst upstream of a PGM-containing ammonia oxidation catalyst and methods of using the system are described. The system allows for high ammonia oxidation with good nitrogen selectivity. Methods of making and using the ammonia slip catalyst to reduce ammonia slip and selectively convert ammonia to N.sub.2 are described.

A diesel particulate filter coated with selective catalytic reduction includes: a support in which channels are formed from a front side to a rear side, a perovskite catalyst, and a selective catalytic reduction. In particular, the channels include an inlet channel which has an opened inlet and a closed outlet, and an outlet channel which is disposed adjacent to the inlet channel and has a closed inlet and an opened outlet. The perovskite catalyst is provided in an inner surface of the inlet channel, and the selective catalytic reduction is provided in an inner surface of the outlet channel. The perovskite catalyst is represented as La.sub.1xAg.sub.xMnO.sub.3 (here, 0<X<1).

Sulfur-resistant synergized platinum group metals (SPGM) catalysts with significant oxidation capabilities are disclosed. Catalytic layers of SPGM catalyst samples are produced using conventional synthesis techniques to build a washcoat layer completely or substantially free of PGM material. The SPGM catalyst includes a washcoat layer comprising YMnO.sub.3 perovskite and an overcoat layer including a Pt composition deposited on a plurality of support oxides with total PGM loading of about 5 g/ft.sup.3. Resistance to sulfur poisoning and catalytic stability is observed under 1.3 gS/L condition to assess the influence that selected support oxides have on the DOC performance of the SPGM catalysts. The results indicate SPGM catalysts produced to include a layer of low amount of PGM catalyst material deposited on a plurality of support oxides added to a layer of ZPGM catalyst material are capable of providing significant improvements in sulfur resistance of SPGM catalyst systems.

A diesel engine exhaust gas treatment system with enhanced nitrogen oxide purification performance includes a nitrogen oxide adsorption part nitrogen adsorbing oxide (NO.sub.x) at a temperature of less than 200 C. and desorbing the nitrogen dioxide (NO.sub.2) at a temperature of 200 C. or more; and a nitrogen oxide purification part disposed at a lower side of the nitrogen oxide adsorption part and purifying the nitrogen oxide (NO.sub.x).

An organic material decomposition catalyst that contains BaCO.sub.3 and a perovskite composite oxide represented by A.sub.xB.sub.yM.sub.zO.sub.w, wherein A contains Ba, B contains Zr, and M denotes Mn. A peak intensity I(BaCO.sub.3(111)) of BaCO.sub.3(111) of the BaCO.sub.3 and a peak intensity I(BaZrO.sub.3(110)) of a perovskite composite oxide A.sub.xB.sub.yM.sub.zO.sub.w(110) of the perovskite composite oxide represented by A.sub.xB.sub.yM.sub.zO.sub.w, each determined by X-ray diffractometry of the organic material decomposition catalyst, have a ratio I(BaCO.sub.3(111))/I(BaZrO.sub.3(110)) in a range of 0.022 to 0.052. In another aspect, in the perovskite composite oxide represented by A.sub.xB.sub.yM.sub.zO.sub.w, 1.01x1.06, 0.1z0.125, and y+z=1 are satisfied, w denotes a positive value that satisfies electroneutrality, and the organic material decomposition catalyst has a specific surface area in the range of 12.3 to 16.9 m.sup.2/g.

A preparation method of perovskite catalyst, represented by the following Chemical Formula 1: La.sub.xAg.sub.(1-x)MnO.sub.3 (0.1x0.9), includes the steps of 1) preparing a metal precursor solution including a lanthanum metal precursor, a manganese metal precursor and a silver metal precursor, 2) adding maleic or citric acid to the metal precursor solution, 3) drying the mixture separately several times with sequentially elevating the temperature in the range of 160 to 210 C., and 4) calcining the dried mixture at 600 to 900 C. for 3 hours to 7 hours.