An organic substance decomposition catalyst that contains a perovskite-type complex oxide denoted by a formula A.sub.xB.sub.yM.sub.zO.sub.w, where A includes Ba, B includes Zr, M represents Mn and Co, a composition ratio of Mn to Co is represented by Mn:Co=z1:z2, z=z1+z2, y+z=1.000, 0.100≤z1+z2≤0.200, 0.00<z1/(z1+z2)<0.75, and w represents a positive value satisfying electrical neutrality.

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, 1.01≤x≤1.06, 0.1≤z≤0.125, 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 catalyst system includes an oxygen storage and release material that has at least one compound of the structure YMO.sub.3+δ, where M is selected from Mn, Co, Cu, Ce, Ti, Ni, Zn, Fe and any combination thereof, and where δ is ≥0. The oxygen storage and release material is configured to allow absorption and release oxygen depending on the conditions of a reagent stream such that sufficient oxygen is maintained for the catalytic removal of at least one of incompletely combusted hydrocarbons, CO, and NO. The catalyst system is useful in a catalytic converter such that oxygen is supplied under rich combustion conditions in an engine upstream of the catalytic converter inlet and oxygen is adsorbed and absorbed under lean rich combustion conditions in the engine.

A supported catalyst for decomposing an organic substance that includes a support and a catalyst particle supported on the support. The catalyst particle contains a perovskite-type composite oxide represented by A.sub.xB.sub.yM.sub.zO.sub.w, where the A contains at least one selected from Ba and Sr, the B contains Zr, the M is at least one selected from Mn, Co, Ni and Fe, y+z=1, x0.995, z0.4, and w is a positive value satisfying electrical neutrality. A film thickness of a catalyst-supporting film supported on the support and containing the catalyst particle is 5 m or more, or a supported amount as determined by normalizing a mass of the catalyst particle supported on the support by a volume of the support is 45 g/L or more.

A supported catalyst for decomposing an organic substance that includes a carrier and catalyst particles supported on the carrier. The catalyst particles contain a perovskite-type composite oxide represented by A.sub.xB.sub.yM.sub.zO.sub.w, where A contains at least one of Ba and Sr, B contains Zr, M is at least one of Mn, Co, Ni, and Fe, y+z=1, x>1, z<0.4, and w is a positive value that satisfies electrical neutrality. An organic substance decomposition rate after the supported catalyst is subjected to a heat treatment at 950 C. for 48 hours is greater than 0.97 when the organic substance decomposition rate before the heat treatment is regarded as 1, and an amount of the catalyst particles peeled off when the supported catalyst is ultrasonicated in water at 28 kHz and 220 W for 15 minutes is less than 1 wt % of the catalyst particles before untrasonication.

Described are catalytic articles comprising a substrate having a washcoat on the substrate, the washcoat containing a catalytic component having a first average (D50) particle size and a functional binder component having a second average (D50) particle size in the range of about 10 nm to about 1000 nm, wherein the ratio of the first average (D50) particle size to the second average (D50) particle size is greater than about 10:1. The catalytic articles are useful in methods and systems to purify exhaust gas streams from an engine.

A catalyst for decomposing an organic substance, the catalyst having a body which has a plurality of pores and the body contains a perovskite-type composite oxide represented by A.sub.xB.sub.yM.sub.zO.sub.w, where the A contains at least one selected from Ba and Sr, the B contains Zr, the M is at least one selected from Mn, Co, Ni, and Fe, 1.001x1.1, 0.05z0.2, y+z=1, and w is a positive value that satisfies electrical neutrality. The average pore diameter of the plurality of pores is 49 nm to 260 nm and the pore volume of each of the plurality of pores is 0.08 cm.sup.3/g to 0.37 cm.sup.3/g.

A honeycomb-structured catalyst for decomposing an organic substance, which includes a catalyst particle. The catalyst particle contains a perovskite-type composite oxide represented by A.sub.xB.sub.yM.sub.zO.sub.w, where the A contains at least of Ba and Sr, the B contains Zr, the M is at least one of Mn, Co, Ni, and Fe, y+z=1, 1.001x1.05, 0.05z0.2, and w is a positive value that satisfies electrical neutrality. The toluene decomposition rate is greater than 90% when toluene is decomposed using the honeycomb-structured catalyst subjected to a heat treatment at 1200 C. for 48 hours and a gas that contains 50 ppm toluene, 80% nitrogen, and 20% oxygen as a volume concentration as a target at a space velocity of 30,000/h and a catalyst temperature of 400 C.

Described are catalytic articles comprising a substrate having a washcoat on the substrate, the washcoat containing a catalytic component having a first average (D50) particle size and a functional binder component having a second average (D50) particle size in the range of about 10 nm to about 1000 nm, wherein the ratio of the first average (D50) particle size to the second average (D50) particle size is greater than about 10:1. The catalytic articles are useful in methods and systems to purify exhaust gas streams from an engine.

A co-catalyst system for the removal of NO.sub.x from an exhaust gas stream has a layered oxide and a spinel of formula Ni.sub.0.15Co.sub.0.85CoAlO.sub.4. The system converts to nitric oxide to nitrogen gas with high product specificity. The layered oxide is configured to convert NO.sub.x in the exhaust gas stream to an N.sub.2O intermediate, and the spinel is configured to convert the N.sub.2O intermediate to N.sub.2.